diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/Kconfig | 30 | ||||
| -rw-r--r-- | kernel/trace/Makefile | 3 | ||||
| -rw-r--r-- | kernel/trace/ftrace.c | 267 | ||||
| -rw-r--r-- | kernel/trace/trace.c | 441 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 46 | ||||
| -rw-r--r-- | kernel/trace/trace_benchmark.c | 198 | ||||
| -rw-r--r-- | kernel/trace/trace_benchmark.h | 41 | ||||
| -rw-r--r-- | kernel/trace/trace_events.c | 13 | ||||
| -rw-r--r-- | kernel/trace/trace_functions.c | 56 | ||||
| -rw-r--r-- | kernel/trace/trace_functions_graph.c | 19 | ||||
| -rw-r--r-- | kernel/trace/trace_irqsoff.c | 71 | ||||
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 3 | ||||
| -rw-r--r-- | kernel/trace/trace_nop.c | 1 | ||||
| -rw-r--r-- | kernel/trace/trace_output.c | 41 | ||||
| -rw-r--r-- | kernel/trace/trace_sched_wakeup.c | 70 | ||||
| -rw-r--r-- | kernel/trace/trace_selftest.c | 69 | ||||
| -rw-r--r-- | kernel/trace/trace_stack.c | 42 |
17 files changed, 951 insertions, 460 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 8639819f6ce..d4409356f40 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -535,6 +535,36 @@ config MMIOTRACE_TEST Say N, unless you absolutely know what you are doing. +config TRACEPOINT_BENCHMARK + bool "Add tracepoint that benchmarks tracepoints" + help + This option creates the tracepoint "benchmark:benchmark_event". + When the tracepoint is enabled, it kicks off a kernel thread that + goes into an infinite loop (calling cond_sched() to let other tasks + run), and calls the tracepoint. Each iteration will record the time + it took to write to the tracepoint and the next iteration that + data will be passed to the tracepoint itself. That is, the tracepoint + will report the time it took to do the previous tracepoint. + The string written to the tracepoint is a static string of 128 bytes + to keep the time the same. The initial string is simply a write of + "START". The second string records the cold cache time of the first + write which is not added to the rest of the calculations. + + As it is a tight loop, it benchmarks as hot cache. That's fine because + we care most about hot paths that are probably in cache already. + + An example of the output: + + START + first=3672 [COLD CACHED] + last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712 + last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337 + last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064 + last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411 + last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389 + last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666 + + config RING_BUFFER_BENCHMARK tristate "Ring buffer benchmark stress tester" depends on RING_BUFFER diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 1378e84fbe3..2611613f14f 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -17,6 +17,7 @@ ifdef CONFIG_TRACING_BRANCHES KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING endif +CFLAGS_trace_benchmark.o := -I$(src) CFLAGS_trace_events_filter.o := -I$(src) obj-$(CONFIG_TRACE_CLOCK) += trace_clock.o @@ -62,4 +63,6 @@ endif obj-$(CONFIG_PROBE_EVENTS) += trace_probe.o obj-$(CONFIG_UPROBE_EVENT) += trace_uprobe.o +obj-$(CONFIG_TRACEPOINT_BENCHMARK) += trace_benchmark.o + libftrace-y := ftrace.o diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 4a54a25afa2..5b372e3ed67 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -62,7 +62,7 @@ #define FTRACE_HASH_DEFAULT_BITS 10 #define FTRACE_HASH_MAX_BITS 12 -#define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_CONTROL) +#define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_CONTROL) #ifdef CONFIG_DYNAMIC_FTRACE #define INIT_REGEX_LOCK(opsname) \ @@ -103,7 +103,6 @@ static int ftrace_disabled __read_mostly; static DEFINE_MUTEX(ftrace_lock); -static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end; static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end; static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end; ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; @@ -171,23 +170,6 @@ int ftrace_nr_registered_ops(void) return cnt; } -static void -ftrace_global_list_func(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *regs) -{ - int bit; - - bit = trace_test_and_set_recursion(TRACE_GLOBAL_START, TRACE_GLOBAL_MAX); - if (bit < 0) - return; - - do_for_each_ftrace_op(op, ftrace_global_list) { - op->func(ip, parent_ip, op, regs); - } while_for_each_ftrace_op(op); - - trace_clear_recursion(bit); -} - static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *regs) { @@ -237,43 +219,6 @@ static int control_ops_alloc(struct ftrace_ops *ops) return 0; } -static void update_global_ops(void) -{ - ftrace_func_t func = ftrace_global_list_func; - void *private = NULL; - - /* The list has its own recursion protection. */ - global_ops.flags |= FTRACE_OPS_FL_RECURSION_SAFE; - - /* - * If there's only one function registered, then call that - * function directly. Otherwise, we need to iterate over the - * registered callers. - */ - if (ftrace_global_list == &ftrace_list_end || - ftrace_global_list->next == &ftrace_list_end) { - func = ftrace_global_list->func; - private = ftrace_global_list->private; - /* - * As we are calling the function directly. - * If it does not have recursion protection, - * the function_trace_op needs to be updated - * accordingly. - */ - if (!(ftrace_global_list->flags & FTRACE_OPS_FL_RECURSION_SAFE)) - global_ops.flags &= ~FTRACE_OPS_FL_RECURSION_SAFE; - } - - /* If we filter on pids, update to use the pid function */ - if (!list_empty(&ftrace_pids)) { - set_ftrace_pid_function(func); - func = ftrace_pid_func; - } - - global_ops.func = func; - global_ops.private = private; -} - static void ftrace_sync(struct work_struct *work) { /* @@ -301,8 +246,6 @@ static void update_ftrace_function(void) { ftrace_func_t func; - update_global_ops(); - /* * If we are at the end of the list and this ops is * recursion safe and not dynamic and the arch supports passing ops, @@ -314,10 +257,7 @@ static void update_ftrace_function(void) (ftrace_ops_list->flags & FTRACE_OPS_FL_RECURSION_SAFE) && !FTRACE_FORCE_LIST_FUNC)) { /* Set the ftrace_ops that the arch callback uses */ - if (ftrace_ops_list == &global_ops) - set_function_trace_op = ftrace_global_list; - else - set_function_trace_op = ftrace_ops_list; + set_function_trace_op = ftrace_ops_list; func = ftrace_ops_list->func; } else { /* Just use the default ftrace_ops */ @@ -373,6 +313,11 @@ static void update_ftrace_function(void) ftrace_trace_function = func; } +int using_ftrace_ops_list_func(void) +{ + return ftrace_trace_function == ftrace_ops_list_func; +} + static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops) { ops->next = *list; @@ -434,16 +379,9 @@ static int __register_ftrace_function(struct ftrace_ops *ops) if (ops->flags & FTRACE_OPS_FL_DELETED) return -EINVAL; - if (FTRACE_WARN_ON(ops == &global_ops)) - return -EINVAL; - if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED)) return -EBUSY; - /* We don't support both control and global flags set. */ - if ((ops->flags & FL_GLOBAL_CONTROL_MASK) == FL_GLOBAL_CONTROL_MASK) - return -EINVAL; - #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS /* * If the ftrace_ops specifies SAVE_REGS, then it only can be used @@ -461,10 +399,7 @@ static int __register_ftrace_function(struct ftrace_ops *ops) if (!core_kernel_data((unsigned long)ops)) ops->flags |= FTRACE_OPS_FL_DYNAMIC; - if (ops->flags & FTRACE_OPS_FL_GLOBAL) { - add_ftrace_list_ops(&ftrace_global_list, &global_ops, ops); - ops->flags |= FTRACE_OPS_FL_ENABLED; - } else if (ops->flags & FTRACE_OPS_FL_CONTROL) { + if (ops->flags & FTRACE_OPS_FL_CONTROL) { if (control_ops_alloc(ops)) return -ENOMEM; add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops); @@ -484,15 +419,7 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops) if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED))) return -EBUSY; - if (FTRACE_WARN_ON(ops == &global_ops)) - return -EINVAL; - - if (ops->flags & FTRACE_OPS_FL_GLOBAL) { - ret = remove_ftrace_list_ops(&ftrace_global_list, - &global_ops, ops); - if (!ret) - ops->flags &= ~FTRACE_OPS_FL_ENABLED; - } else if (ops->flags & FTRACE_OPS_FL_CONTROL) { + if (ops->flags & FTRACE_OPS_FL_CONTROL) { ret = remove_ftrace_list_ops(&ftrace_control_list, &control_ops, ops); } else @@ -895,7 +822,7 @@ function_profile_call(unsigned long ip, unsigned long parent_ip, local_irq_save(flags); - stat = &__get_cpu_var(ftrace_profile_stats); + stat = this_cpu_ptr(&ftrace_profile_stats); if (!stat->hash || !ftrace_profile_enabled) goto out; @@ -926,7 +853,7 @@ static void profile_graph_return(struct ftrace_graph_ret *trace) unsigned long flags; local_irq_save(flags); - stat = &__get_cpu_var(ftrace_profile_stats); + stat = this_cpu_ptr(&ftrace_profile_stats); if (!stat->hash || !ftrace_profile_enabled) goto out; @@ -1178,7 +1105,7 @@ struct ftrace_page { static struct ftrace_page *ftrace_pages_start; static struct ftrace_page *ftrace_pages; -static bool ftrace_hash_empty(struct ftrace_hash *hash) +static bool __always_inline ftrace_hash_empty(struct ftrace_hash *hash) { return !hash || !hash->count; } @@ -1625,7 +1552,14 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip); /* + * If filter_hash is set, we want to match all functions + * that are in the hash but not in the other hash. * + * If filter_hash is not set, then we are decrementing. + * That means we match anything that is in the hash + * and also in the other_hash. That is, we need to turn + * off functions in the other hash because they are disabled + * by this hash. */ if (filter_hash && in_hash && !in_other_hash) match = 1; @@ -1767,19 +1701,15 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update) /* * If this record is being updated from a nop, then * return UPDATE_MAKE_CALL. - * Otherwise, if the EN flag is set, then return - * UPDATE_MODIFY_CALL_REGS to tell the caller to convert - * from the non-save regs, to a save regs function. * Otherwise, * return UPDATE_MODIFY_CALL to tell the caller to convert - * from the save regs, to a non-save regs function. + * from the save regs, to a non-save regs function or + * vice versa. */ if (flag & FTRACE_FL_ENABLED) return FTRACE_UPDATE_MAKE_CALL; - else if (rec->flags & FTRACE_FL_REGS_EN) - return FTRACE_UPDATE_MODIFY_CALL_REGS; - else - return FTRACE_UPDATE_MODIFY_CALL; + + return FTRACE_UPDATE_MODIFY_CALL; } if (update) { @@ -1821,6 +1751,42 @@ int ftrace_test_record(struct dyn_ftrace *rec, int enable) return ftrace_check_record(rec, enable, 0); } +/** + * ftrace_get_addr_new - Get the call address to set to + * @rec: The ftrace record descriptor + * + * If the record has the FTRACE_FL_REGS set, that means that it + * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS + * is not not set, then it wants to convert to the normal callback. + * + * Returns the address of the trampoline to set to + */ +unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec) +{ + if (rec->flags & FTRACE_FL_REGS) + return (unsigned long)FTRACE_REGS_ADDR; + else + return (unsigned long)FTRACE_ADDR; +} + +/** + * ftrace_get_addr_curr - Get the call address that is already there + * @rec: The ftrace record descriptor + * + * The FTRACE_FL_REGS_EN is set when the record already points to + * a function that saves all the regs. Basically the '_EN' version + * represents the current state of the function. + * + * Returns the address of the trampoline that is currently being called + */ +unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec) +{ + if (rec->flags & FTRACE_FL_REGS_EN) + return (unsigned long)FTRACE_REGS_ADDR; + else + return (unsigned long)FTRACE_ADDR; +} + static int __ftrace_replace_code(struct dyn_ftrace *rec, int enable) { @@ -1828,12 +1794,12 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable) unsigned long ftrace_addr; int ret; - ret = ftrace_update_record(rec, enable); + ftrace_addr = ftrace_get_addr_new(rec); - if (rec->flags & FTRACE_FL_REGS) - ftrace_addr = (unsigned long)FTRACE_REGS_ADDR; - else - ftrace_addr = (unsigned long)FTRACE_ADDR; + /* This needs to be done before we call ftrace_update_record */ + ftrace_old_addr = ftrace_get_addr_curr(rec); + + ret = ftrace_update_record(rec, enable); switch (ret) { case FTRACE_UPDATE_IGNORE: @@ -1845,13 +1811,7 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable) case FTRACE_UPDATE_MAKE_NOP: return ftrace_make_nop(NULL, rec, ftrace_addr); - case FTRACE_UPDATE_MODIFY_CALL_REGS: case FTRACE_UPDATE_MODIFY_CALL: - if (rec->flags & FTRACE_FL_REGS) - ftrace_old_addr = (unsigned long)FTRACE_ADDR; - else - ftrace_old_addr = (unsigned long)FTRACE_REGS_ADDR; - return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr); } @@ -2115,7 +2075,6 @@ static void ftrace_startup_enable(int command) static int ftrace_startup(struct ftrace_ops *ops, int command) { - bool hash_enable = true; int ret; if (unlikely(ftrace_disabled)) @@ -2128,18 +2087,9 @@ static int ftrace_startup(struct ftrace_ops *ops, int command) ftrace_start_up++; command |= FTRACE_UPDATE_CALLS; - /* ops marked global share the filter hashes */ - if (ops->flags & FTRACE_OPS_FL_GLOBAL) { - ops = &global_ops; - /* Don't update hash if global is already set */ - if (global_start_up) - hash_enable = false; - global_start_up++; - } - ops->flags |= FTRACE_OPS_FL_ENABLED; - if (hash_enable) - ftrace_hash_rec_enable(ops, 1); + + ftrace_hash_rec_enable(ops, 1); ftrace_startup_enable(command); @@ -2148,7 +2098,6 @@ static int ftrace_startup(struct ftrace_ops *ops, int command) static int ftrace_shutdown(struct ftrace_ops *ops, int command) { - bool hash_disable = true; int ret; if (unlikely(ftrace_disabled)) @@ -2166,21 +2115,9 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command) */ WARN_ON_ONCE(ftrace_start_up < 0); - if (ops->flags & FTRACE_OPS_FL_GLOBAL) { - ops = &global_ops; - global_start_up--; - WARN_ON_ONCE(global_start_up < 0); - /* Don't update hash if global still has users */ - if (global_start_up) { - WARN_ON_ONCE(!ftrace_start_up); - hash_disable = false; - } - } - - if (hash_disable) - ftrace_hash_rec_disable(ops, 1); + ftrace_hash_rec_disable(ops, 1); - if (ops != &global_ops || !global_start_up) + if (!global_start_up) ops->flags &= ~FTRACE_OPS_FL_ENABLED; command |= FTRACE_UPDATE_CALLS; @@ -3524,10 +3461,6 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len, struct ftrace_hash *hash; int ret; - /* All global ops uses the global ops filters */ - if (ops->flags & FTRACE_OPS_FL_GLOBAL) - ops = &global_ops; - if (unlikely(ftrace_disabled)) return -ENODEV; @@ -3639,8 +3572,7 @@ int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, } EXPORT_SYMBOL_GPL(ftrace_set_notrace); /** - * ftrace_set_filter - set a function to filter on in ftrace - * @ops - the ops to set the filter with + * ftrace_set_global_filter - set a function to filter on with global tracers * @buf - the string that holds the function filter text. * @len - the length of the string. * @reset - non zero to reset all filters before applying this filter. @@ -3655,8 +3587,7 @@ void ftrace_set_global_filter(unsigned char *buf, int len, int reset) EXPORT_SYMBOL_GPL(ftrace_set_global_filter); /** - * ftrace_set_notrace - set a function to not trace in ftrace - * @ops - the ops to set the notrace filter with + * ftrace_set_global_notrace - set a function to not trace with global tracers * @buf - the string that holds the function notrace text. * @len - the length of the string. * @reset - non zero to reset all filters before applying this filter. @@ -4443,6 +4374,34 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs) #endif /* CONFIG_DYNAMIC_FTRACE */ +__init void ftrace_init_global_array_ops(struct trace_array *tr) +{ + tr->ops = &global_ops; + tr->ops->private = tr; +} + +void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func) +{ + /* If we filter on pids, update to use the pid function */ + if (tr->flags & TRACE_ARRAY_FL_GLOBAL) { + if (WARN_ON(tr->ops->func != ftrace_stub)) + printk("ftrace ops had %pS for function\n", + tr->ops->func); + /* Only the top level instance does pid tracing */ + if (!list_empty(&ftrace_pids)) { + set_ftrace_pid_function(func); + func = ftrace_pid_func; + } + } + tr->ops->func = func; + tr->ops->private = tr; +} + +void ftrace_reset_array_ops(struct trace_array *tr) +{ + tr->ops->func = ftrace_stub; +} + static void ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *regs) @@ -4501,9 +4460,16 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, */ preempt_disable_notrace(); do_for_each_ftrace_op(op, ftrace_ops_list) { - if (ftrace_ops_test(op, ip, regs)) + if (ftrace_ops_test(op, ip, regs)) { + if (WARN_ON(!op->func)) { + function_trace_stop = 1; + printk("op=%p %pS\n", op, op); + goto out; + } op->func(ip, parent_ip, op, regs); + } } while_for_each_ftrace_op(op); +out: preempt_enable_notrace(); trace_clear_recursion(bit); } @@ -4908,7 +4874,6 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, #ifdef CONFIG_FUNCTION_GRAPH_TRACER static int ftrace_graph_active; -static struct notifier_block ftrace_suspend_notifier; int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace) { @@ -5054,13 +5019,6 @@ ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state, return NOTIFY_DONE; } -/* Just a place holder for function graph */ -static struct ftrace_ops fgraph_ops __read_mostly = { - .func = ftrace_stub, - .flags = FTRACE_OPS_FL_STUB | FTRACE_OPS_FL_GLOBAL | - FTRACE_OPS_FL_RECURSION_SAFE, -}; - static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace) { if (!ftrace_ops_test(&global_ops, trace->func, NULL)) @@ -5085,6 +5043,10 @@ static void update_function_graph_func(void) ftrace_graph_entry = ftrace_graph_entry_test; } +static struct notifier_block ftrace_suspend_notifier = { + .notifier_call = ftrace_suspend_notifier_call, +}; + int register_ftrace_graph(trace_func_graph_ret_t retfunc, trace_func_graph_ent_t entryfunc) { @@ -5098,7 +5060,6 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc, goto out; } - ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call; register_pm_notifier(&ftrace_suspend_notifier); ftrace_graph_active++; @@ -5120,7 +5081,10 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc, ftrace_graph_entry = ftrace_graph_entry_test; update_function_graph_func(); - ret = ftrace_startup(&fgraph_ops, FTRACE_START_FUNC_RET); + /* Function graph doesn't use the .func field of global_ops */ + global_ops.flags |= FTRACE_OPS_FL_STUB; + + ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET); out: mutex_unlock(&ftrace_lock); @@ -5138,7 +5102,8 @@ void unregister_ftrace_graph(void) ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub; ftrace_graph_entry = ftrace_graph_entry_stub; __ftrace_graph_entry = ftrace_graph_entry_stub; - ftrace_shutdown(&fgraph_ops, FTRACE_STOP_FUNC_RET); + ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET); + global_ops.flags &= ~FTRACE_OPS_FL_STUB; unregister_pm_notifier(&ftrace_suspend_notifier); unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 737b0efa1a6..16f7038d1f4 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -275,7 +275,7 @@ int call_filter_check_discard(struct ftrace_event_call *call, void *rec, } EXPORT_SYMBOL_GPL(call_filter_check_discard); -cycle_t buffer_ftrace_now(struct trace_buffer *buf, int cpu) +static cycle_t buffer_ftrace_now(struct trace_buffer *buf, int cpu) { u64 ts; @@ -599,7 +599,7 @@ static int alloc_snapshot(struct trace_array *tr) return 0; } -void free_snapshot(struct trace_array *tr) +static void free_snapshot(struct trace_array *tr) { /* * We don't free the ring buffer. instead, resize it because @@ -963,27 +963,9 @@ static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt) return cnt; } -/* - * ftrace_max_lock is used to protect the swapping of buffers - * when taking a max snapshot. The buffers themselves are - * protected by per_cpu spinlocks. But the action of the swap - * needs its own lock. - * - * This is defined as a arch_spinlock_t in order to help - * with performance when lockdep debugging is enabled. - * - * It is also used in other places outside the update_max_tr - * so it needs to be defined outside of the - * CONFIG_TRACER_MAX_TRACE. - */ -static arch_spinlock_t ftrace_max_lock = - (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; - unsigned long __read_mostly tracing_thresh; #ifdef CONFIG_TRACER_MAX_TRACE -unsigned long __read_mostly tracing_max_latency; - /* * Copy the new maximum trace into the separate maximum-trace * structure. (this way the maximum trace is permanently saved, @@ -1000,7 +982,7 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) max_buf->cpu = cpu; max_buf->time_start = data->preempt_timestamp; - max_data->saved_latency = tracing_max_latency; + max_data->saved_latency = tr->max_latency; max_data->critical_start = data->critical_start; max_data->critical_end = data->critical_end; @@ -1048,14 +1030,14 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) return; } - arch_spin_lock(&ftrace_max_lock); + arch_spin_lock(&tr->max_lock); buf = tr->trace_buffer.buffer; tr->trace_buffer.buffer = tr->max_buffer.buffer; tr->max_buffer.buffer = buf; __update_max_tr(tr, tsk, cpu); - arch_spin_unlock(&ftrace_max_lock); + arch_spin_unlock(&tr->max_lock); } /** @@ -1081,7 +1063,7 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) return; } - arch_spin_lock(&ftrace_max_lock); + arch_spin_lock(&tr->max_lock); ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->trace_buffer.buffer, cpu); @@ -1099,11 +1081,11 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY); __update_max_tr(tr, tsk, cpu); - arch_spin_unlock(&ftrace_max_lock); + arch_spin_unlock(&tr->max_lock); } #endif /* CONFIG_TRACER_MAX_TRACE */ -static void default_wait_pipe(struct trace_iterator *iter) +static void wait_on_pipe(struct trace_iterator *iter) { /* Iterators are static, they should be filled or empty */ if (trace_buffer_iter(iter, iter->cpu_file)) @@ -1220,8 +1202,6 @@ int register_tracer(struct tracer *type) else if (!type->flags->opts) type->flags->opts = dummy_tracer_opt; - if (!type->wait_pipe) - type->wait_pipe = default_wait_pipe; ret = run_tracer_selftest(type); if (ret < 0) @@ -1305,22 +1285,71 @@ void tracing_reset_all_online_cpus(void) } } -#define SAVED_CMDLINES 128 +#define SAVED_CMDLINES_DEFAULT 128 #define NO_CMDLINE_MAP UINT_MAX -static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1]; -static unsigned map_cmdline_to_pid[SAVED_CMDLINES]; -static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN]; -static int cmdline_idx; static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED; +struct saved_cmdlines_buffer { + unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1]; + unsigned *map_cmdline_to_pid; + unsigned cmdline_num; + int cmdline_idx; + char *saved_cmdlines; +}; +static struct saved_cmdlines_buffer *savedcmd; /* temporary disable recording */ static atomic_t trace_record_cmdline_disabled __read_mostly; -static void trace_init_cmdlines(void) +static inline char *get_saved_cmdlines(int idx) { - memset(&map_pid_to_cmdline, NO_CMDLINE_MAP, sizeof(map_pid_to_cmdline)); - memset(&map_cmdline_to_pid, NO_CMDLINE_MAP, sizeof(map_cmdline_to_pid)); - cmdline_idx = 0; + return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN]; +} + +static inline void set_cmdline(int idx, const char *cmdline) +{ + memcpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN); +} + +static int allocate_cmdlines_buffer(unsigned int val, + struct saved_cmdlines_buffer *s) +{ + s->map_cmdline_to_pid = kmalloc(val * sizeof(*s->map_cmdline_to_pid), + GFP_KERNEL); + if (!s->map_cmdline_to_pid) + return -ENOMEM; + + s->saved_cmdlines = kmalloc(val * TASK_COMM_LEN, GFP_KERNEL); + if (!s->saved_cmdlines) { + kfree(s->map_cmdline_to_pid); + return -ENOMEM; + } + + s->cmdline_idx = 0; + s->cmdline_num = val; + memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP, + sizeof(s->map_pid_to_cmdline)); + memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP, + val * sizeof(*s->map_cmdline_to_pid)); + + return 0; +} + +static int trace_create_savedcmd(void) +{ + int ret; + + savedcmd = kmalloc(sizeof(struct saved_cmdlines_buffer), GFP_KERNEL); + if (!savedcmd) + return -ENOMEM; + + ret = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT, savedcmd); + if (ret < 0) { + kfree(savedcmd); + savedcmd = NULL; + return -ENOMEM; + } + + return 0; } int is_tracing_stopped(void) @@ -1353,7 +1382,7 @@ void tracing_start(void) } /* Prevent the buffers from switching */ - arch_spin_lock(&ftrace_max_lock); + arch_spin_lock(&global_trace.max_lock); buffer = global_trace.trace_buffer.buffer; if (buffer) @@ -1365,7 +1394,7 @@ void tracing_start(void) ring_buffer_record_enable(buffer); #endif - arch_spin_unlock(&ftrace_max_lock); + arch_spin_unlock(&global_trace.max_lock); ftrace_start(); out: @@ -1420,7 +1449,7 @@ void tracing_stop(void) goto out; /* Prevent the buffers from switching */ - arch_spin_lock(&ftrace_max_lock); + arch_spin_lock(&global_trace.max_lock); buffer = global_trace.trace_buffer.buffer; if (buffer) @@ -1432,7 +1461,7 @@ void tracing_stop(void) ring_buffer_record_disable(buffer); #endif - arch_spin_unlock(&ftrace_max_lock); + arch_spin_unlock(&global_trace.max_lock); out: raw_spin_unlock_irqrestore(&global_trace.start_lock, flags); @@ -1461,12 +1490,12 @@ static void tracing_stop_tr(struct trace_array *tr) void trace_stop_cmdline_recording(void); -static void trace_save_cmdline(struct task_struct *tsk) +static int trace_save_cmdline(struct task_struct *tsk) { unsigned pid, idx; if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT)) - return; + return 0; /* * It's not the end of the world if we don't get @@ -1475,11 +1504,11 @@ static void trace_save_cmdline(struct task_struct *tsk) * so if we miss here, then better luck next time. */ if (!arch_spin_trylock(&trace_cmdline_lock)) - return; + return 0; - idx = map_pid_to_cmdline[tsk->pid]; + idx = savedcmd->map_pid_to_cmdline[tsk->pid]; if (idx == NO_CMDLINE_MAP) { - idx = (cmdline_idx + 1) % SAVED_CMDLINES; + idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num; /* * Check whether the cmdline buffer at idx has a pid @@ -1487,22 +1516,24 @@ static void trace_save_cmdline(struct task_struct *tsk) * need to clear the map_pid_to_cmdline. Otherwise we * would read the new comm for the old pid. */ - pid = map_cmdline_to_pid[idx]; + pid = savedcmd->map_cmdline_to_pid[idx]; if (pid != NO_CMDLINE_MAP) - map_pid_to_cmdline[pid] = NO_CMDLINE_MAP; + savedcmd->map_pid_to_cmdline[pid] = NO_CMDLINE_MAP; - map_cmdline_to_pid[idx] = tsk->pid; - map_pid_to_cmdline[tsk->pid] = idx; + savedcmd->map_cmdline_to_pid[idx] = tsk->pid; + savedcmd->map_pid_to_cmdline[tsk->pid] = idx; - cmdline_idx = idx; + savedcmd->cmdline_idx = idx; } - memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN); + set_cmdline(idx, tsk->comm); arch_spin_unlock(&trace_cmdline_lock); + + return 1; } -void trace_find_cmdline(int pid, char comm[]) +static void __trace_find_cmdline(int pid, char comm[]) { unsigned map; @@ -1521,13 +1552,19 @@ void trace_find_cmdline(int pid, char comm[]) return; } - preempt_disable(); - arch_spin_lock(&trace_cmdline_lock); - map = map_pid_to_cmdline[pid]; + map = savedcmd->map_pid_to_cmdline[pid]; if (map != NO_CMDLINE_MAP) - strcpy(comm, saved_cmdlines[map]); + strcpy(comm, get_saved_cmdlines(map)); else strcpy(comm, "<...>"); +} + +void trace_find_cmdline(int pid, char comm[]) +{ + preempt_disable(); + arch_spin_lock(&trace_cmdline_lock); + + __trace_find_cmdline(pid, comm); arch_spin_unlock(&trace_cmdline_lock); preempt_enable(); @@ -1541,9 +1578,8 @@ void tracing_record_cmdline(struct task_struct *tsk) if (!__this_cpu_read(trace_cmdline_save)) return; - __this_cpu_write(trace_cmdline_save, false); - - trace_save_cmdline(tsk); + if (trace_save_cmdline(tsk)) + __this_cpu_write(trace_cmdline_save, false); } void @@ -1746,7 +1782,7 @@ static void __ftrace_trace_stack(struct ring_buffer *buffer, */ barrier(); if (use_stack == 1) { - trace.entries = &__get_cpu_var(ftrace_stack).calls[0]; + trace.entries = this_cpu_ptr(ftrace_stack.calls); trace.max_entries = FTRACE_STACK_MAX_ENTRIES; if (regs) @@ -1995,7 +2031,21 @@ void trace_printk_init_buffers(void) if (alloc_percpu_trace_buffer()) return; - pr_info("ftrace: Allocated trace_printk buffers\n"); + /* trace_printk() is for debug use only. Don't use it in production. */ + + pr_warning("\n**********************************************************\n"); + pr_warning("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n"); + pr_warning("** **\n"); + pr_warning("** trace_printk() being used. Allocating extra memory. **\n"); + pr_warning("** **\n"); + pr_warning("** This means that this is a DEBUG kernel and it is **\n"); + pr_warning("** unsafe for produciton use. **\n"); + pr_warning("** **\n"); + pr_warning("** If you see this message and you are not debugging **\n"); + pr_warning("** the kernel, report this immediately to your vendor! **\n"); + pr_warning("** **\n"); + pr_warning("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n"); + pr_warning("**********************************************************\n"); /* Expand the buffers to set size */ tracing_update_buffers(); @@ -3333,7 +3383,7 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf, mutex_lock(&tracing_cpumask_update_lock); local_irq_disable(); - arch_spin_lock(&ftrace_max_lock); + arch_spin_lock(&tr->max_lock); for_each_tracing_cpu(cpu) { /* * Increase/decrease the disabled counter if we are @@ -3350,7 +3400,7 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf, ring_buffer_record_enable_cpu(tr->trace_buffer.buffer, cpu); } } - arch_spin_unlock(&ftrace_max_lock); + arch_spin_unlock(&tr->max_lock); local_irq_enable(); cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new); @@ -3592,6 +3642,7 @@ static const char readme_msg[] = " trace_options\t\t- Set format or modify how tracing happens\n" "\t\t\t Disable an option by adding a suffix 'no' to the\n" "\t\t\t option name\n" + " saved_cmdlines_size\t- echo command number in here to store comm-pid list\n" #ifdef CONFIG_DYNAMIC_FTRACE "\n available_filter_functions - list of functions that can be filtered on\n" " set_ftrace_filter\t- echo function name in here to only trace these\n" @@ -3705,55 +3756,153 @@ static const struct file_operations tracing_readme_fops = { .llseek = generic_file_llseek, }; +static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos) +{ + unsigned int *ptr = v; + + if (*pos || m->count) + ptr++; + + (*pos)++; + + for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num]; + ptr++) { + if (*ptr == -1 || *ptr == NO_CMDLINE_MAP) + continue; + + return ptr; + } + + return NULL; +} + +static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos) +{ + void *v; + loff_t l = 0; + + preempt_disable(); + arch_spin_lock(&trace_cmdline_lock); + + v = &savedcmd->map_cmdline_to_pid[0]; + while (l <= *pos) { + v = saved_cmdlines_next(m, v, &l); + if (!v) + return NULL; + } + + return v; +} + +static void saved_cmdlines_stop(struct seq_file *m, void *v) +{ + arch_spin_unlock(&trace_cmdline_lock); + preempt_enable(); +} + +static int saved_cmdlines_show(struct seq_file *m, void *v) +{ + char buf[TASK_COMM_LEN]; + unsigned int *pid = v; + + __trace_find_cmdline(*pid, buf); + seq_printf(m, "%d %s\n", *pid, buf); + return 0; +} + +static const struct seq_operations tracing_saved_cmdlines_seq_ops = { + .start = saved_cmdlines_start, + .next = saved_cmdlines_next, + .stop = saved_cmdlines_stop, + .show = saved_cmdlines_show, +}; + +static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp) +{ + if (tracing_disabled) + return -ENODEV; + + return seq_open(filp, &tracing_saved_cmdlines_seq_ops); +} + +static const struct file_operations tracing_saved_cmdlines_fops = { + .open = tracing_saved_cmdlines_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + static ssize_t -tracing_saved_cmdlines_read(struct file *file, char __user *ubuf, - size_t cnt, loff_t *ppos) +tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) { - char *buf_comm; - char *file_buf; - char *buf; - int len = 0; - int pid; - int i; + char buf[64]; + int r; + + arch_spin_lock(&trace_cmdline_lock); + r = sprintf(buf, "%u\n", savedcmd->cmdline_num); + arch_spin_unlock(&trace_cmdline_lock); + + return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); +} + +static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s) +{ + kfree(s->saved_cmdlines); + kfree(s->map_cmdline_to_pid); + kfree(s); +} + +static int tracing_resize_saved_cmdlines(unsigned int val) +{ + struct saved_cmdlines_buffer *s, *savedcmd_temp; - file_buf = kmalloc(SAVED_CMDLINES*(16+TASK_COMM_LEN), GFP_KERNEL); - if (!file_buf) + s = kmalloc(sizeof(struct saved_cmdlines_buffer), GFP_KERNEL); + if (!s) return -ENOMEM; - buf_comm = kmalloc(TASK_COMM_LEN, GFP_KERNEL); - if (!buf_comm) { - kfree(file_buf); + if (allocate_cmdlines_buffer(val, s) < 0) { + kfree(s); return -ENOMEM; } - buf = file_buf; + arch_spin_lock(&trace_cmdline_lock); + savedcmd_temp = savedcmd; + savedcmd = s; + arch_spin_unlock(&trace_cmdline_lock); + free_saved_cmdlines_buffer(savedcmd_temp); - for (i = 0; i < SAVED_CMDLINES; i++) { - int r; + return 0; +} - pid = map_cmdline_to_pid[i]; - if (pid == -1 || pid == NO_CMDLINE_MAP) - continue; +static ssize_t +tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + unsigned long val; + int ret; - trace_find_cmdline(pid, buf_comm); - r = sprintf(buf, "%d %s\n", pid, buf_comm); - buf += r; - len += r; - } + ret = kstrtoul_from_user(ubuf, cnt, 10, &val); + if (ret) + return ret; - len = simple_read_from_buffer(ubuf, cnt, ppos, - file_buf, len); + /* must have at least 1 entry or less than PID_MAX_DEFAULT */ + if (!val || val > PID_MAX_DEFAULT) + return -EINVAL; - kfree(file_buf); - kfree(buf_comm); + ret = tracing_resize_saved_cmdlines((unsigned int)val); + if (ret < 0) + return ret; - return len; + *ppos += cnt; + + return cnt; } -static const struct file_operations tracing_saved_cmdlines_fops = { - .open = tracing_open_generic, - .read = tracing_saved_cmdlines_read, - .llseek = generic_file_llseek, +static const struct file_operations tracing_saved_cmdlines_size_fops = { + .open = tracing_open_generic, + .read = tracing_saved_cmdlines_size_read, + .write = tracing_saved_cmdlines_size_write, }; static ssize_t @@ -4225,25 +4374,6 @@ tracing_poll_pipe(struct file *filp, poll_table *poll_table) return trace_poll(iter, filp, poll_table); } -/* - * This is a make-shift waitqueue. - * A tracer might use this callback on some rare cases: - * - * 1) the current tracer might hold the runqueue lock when it wakes up - * a reader, hence a deadlock (sched, function, and function graph tracers) - * 2) the function tracers, trace all functions, we don't want - * the overhead of calling wake_up and friends - * (and tracing them too) - * - * Anyway, this is really very primitive wakeup. - */ -void poll_wait_pipe(struct trace_iterator *iter) -{ - set_current_state(TASK_INTERRUPTIBLE); - /* sleep for 100 msecs, and try again. */ - schedule_timeout(HZ / 10); -} - /* Must be called with trace_types_lock mutex held. */ static int tracing_wait_pipe(struct file *filp) { @@ -4255,15 +4385,6 @@ static int tracing_wait_pipe(struct file *filp) return -EAGAIN; } - mutex_unlock(&iter->mutex); - - iter->trace->wait_pipe(iter); - - mutex_lock(&iter->mutex); - - if (signal_pending(current)) - return -EINTR; - /* * We block until we read something and tracing is disabled. * We still block if tracing is disabled, but we have never @@ -4275,6 +4396,15 @@ static int tracing_wait_pipe(struct file *filp) */ if (!tracing_is_on() && iter->pos) break; + + mutex_unlock(&iter->mutex); + + wait_on_pipe(iter); + + mutex_lock(&iter->mutex); + + if (signal_pending(current)) + return -EINTR; } return 1; @@ -5197,7 +5327,7 @@ tracing_buffers_read(struct file *filp, char __user *ubuf, goto out_unlock; } mutex_unlock(&trace_types_lock); - iter->trace->wait_pipe(iter); + wait_on_pipe(iter); mutex_lock(&trace_types_lock); if (signal_pending(current)) { size = -EINTR; @@ -5408,7 +5538,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, goto out; } mutex_unlock(&trace_types_lock); - iter->trace->wait_pipe(iter); + wait_on_pipe(iter); mutex_lock(&trace_types_lock); if (signal_pending(current)) { ret = -EINTR; @@ -6102,6 +6232,25 @@ static int allocate_trace_buffers(struct trace_array *tr, int size) return 0; } +static void free_trace_buffers(struct trace_array *tr) +{ + if (!tr) + return; + + if (tr->trace_buffer.buffer) { + ring_buffer_free(tr->trace_buffer.buffer); + tr->trace_buffer.buffer = NULL; + free_percpu(tr->trace_buffer.data); + } + +#ifdef CONFIG_TRACER_MAX_TRACE + if (tr->max_buffer.buffer) { + ring_buffer_free(tr->max_buffer.buffer); + tr->max_buffer.buffer = NULL; + } +#endif +} + static int new_instance_create(const char *name) { struct trace_array *tr; @@ -6131,6 +6280,8 @@ static int new_instance_create(const char *name) raw_spin_lock_init(&tr->start_lock); + tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; + tr->current_trace = &nop_trace; INIT_LIST_HEAD(&tr->systems); @@ -6158,8 +6309,7 @@ static int new_instance_create(const char *name) return 0; out_free_tr: - if (tr->trace_buffer.buffer) - ring_buffer_free(tr->trace_buffer.buffer); + free_trace_buffers(tr); free_cpumask_var(tr->tracing_cpumask); kfree(tr->name); kfree(tr); @@ -6199,8 +6349,7 @@ static int instance_delete(const char *name) event_trace_del_tracer(tr); ftrace_destroy_function_files(tr); debugfs_remove_recursive(tr->dir); - free_percpu(tr->trace_buffer.data); - ring_buffer_free(tr->trace_buffer.buffer); + free_trace_buffers(tr); kfree(tr->name); kfree(tr); @@ -6328,6 +6477,11 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer) trace_create_file("tracing_on", 0644, d_tracer, tr, &rb_simple_fops); +#ifdef CONFIG_TRACER_MAX_TRACE + trace_create_file("tracing_max_latency", 0644, d_tracer, + &tr->max_latency, &tracing_max_lat_fops); +#endif + if (ftrace_create_function_files(tr, d_tracer)) WARN(1, "Could not allocate function filter files"); @@ -6353,11 +6507,6 @@ static __init int tracer_init_debugfs(void) init_tracer_debugfs(&global_trace, d_tracer); -#ifdef CONFIG_TRACER_MAX_TRACE - trace_create_file("tracing_max_latency", 0644, d_tracer, - &tracing_max_latency, &tracing_max_lat_fops); -#endif - trace_create_file("tracing_thresh", 0644, d_tracer, &tracing_thresh, &tracing_max_lat_fops); @@ -6367,6 +6516,9 @@ static __init int tracer_init_debugfs(void) trace_create_file("saved_cmdlines", 0444, d_tracer, NULL, &tracing_saved_cmdlines_fops); + trace_create_file("saved_cmdlines_size", 0644, d_tracer, + NULL, &tracing_saved_cmdlines_size_fops); + #ifdef CONFIG_DYNAMIC_FTRACE trace_create_file("dyn_ftrace_total_info", 0444, d_tracer, &ftrace_update_tot_cnt, &tracing_dyn_info_fops); @@ -6603,18 +6755,19 @@ __init static int tracer_alloc_buffers(void) if (!temp_buffer) goto out_free_cpumask; + if (trace_create_savedcmd() < 0) + goto out_free_temp_buffer; + /* TODO: make the number of buffers hot pluggable with CPUS */ if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) { printk(KERN_ERR "tracer: failed to allocate ring buffer!\n"); WARN_ON(1); - goto out_free_temp_buffer; + goto out_free_savedcmd; } if (global_trace.buffer_disabled) tracing_off(); - trace_init_cmdlines(); - if (trace_boot_clock) { ret = tracing_set_clock(&global_trace, trace_boot_clock); if (ret < 0) @@ -6629,6 +6782,10 @@ __init static int tracer_alloc_buffers(void) */ global_trace.current_trace = &nop_trace; + global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; + + ftrace_init_global_array_ops(&global_trace); + register_tracer(&nop_trace); /* All seems OK, enable tracing */ @@ -6656,13 +6813,11 @@ __init static int tracer_alloc_buffers(void) return 0; +out_free_savedcmd: + free_saved_cmdlines_buffer(savedcmd); out_free_temp_buffer: ring_buffer_free(temp_buffer); out_free_cpumask: - free_percpu(global_trace.trace_buffer.data); -#ifdef CONFIG_TRACER_MAX_TRACE - free_percpu(global_trace.max_buffer.data); -#endif free_cpumask_var(global_trace.tracing_cpumask); out_free_buffer_mask: free_cpumask_var(tracing_buffer_mask); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 2e29d7ba5a5..9e82551dd56 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -190,7 +190,22 @@ struct trace_array { */ struct trace_buffer max_buffer; bool allocated_snapshot; + unsigned long max_latency; #endif + /* + * max_lock is used to protect the swapping of buffers + * when taking a max snapshot. The buffers themselves are + * protected by per_cpu spinlocks. But the action of the swap + * needs its own lock. + * + * This is defined as a arch_spinlock_t in order to help + * with performance when lockdep debugging is enabled. + * + * It is also used in other places outside the update_max_tr + * so it needs to be defined outside of the + * CONFIG_TRACER_MAX_TRACE. + */ + arch_spinlock_t max_lock; int buffer_disabled; #ifdef CONFIG_FTRACE_SYSCALLS int sys_refcount_enter; @@ -237,6 +252,9 @@ static inline struct trace_array *top_trace_array(void) { struct trace_array *tr; + if (list_empty(ftrace_trace_arrays.prev)) + return NULL; + tr = list_entry(ftrace_trace_arrays.prev, typeof(*tr), list); WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL)); @@ -323,7 +341,6 @@ struct tracer_flags { * @stop: called when tracing is paused (echo 0 > tracing_enabled) * @open: called when the trace file is opened * @pipe_open: called when the trace_pipe file is opened - * @wait_pipe: override how the user waits for traces on trace_pipe * @close: called when the trace file is released * @pipe_close: called when the trace_pipe file is released * @read: override the default read callback on trace_pipe @@ -342,7 +359,6 @@ struct tracer { void (*stop)(struct trace_array *tr); void (*open)(struct trace_iterator *iter); void (*pipe_open)(struct trace_iterator *iter); - void (*wait_pipe)(struct trace_iterator *iter); void (*close)(struct trace_iterator *iter); void (*pipe_close)(struct trace_iterator *iter); ssize_t (*read)(struct trace_iterator *iter, @@ -416,13 +432,7 @@ enum { TRACE_FTRACE_IRQ_BIT, TRACE_FTRACE_SIRQ_BIT, - /* GLOBAL_BITs must be greater than FTRACE_BITs */ - TRACE_GLOBAL_BIT, - TRACE_GLOBAL_NMI_BIT, - TRACE_GLOBAL_IRQ_BIT, - TRACE_GLOBAL_SIRQ_BIT, - - /* INTERNAL_BITs must be greater than GLOBAL_BITs */ + /* INTERNAL_BITs must be greater than FTRACE_BITs */ TRACE_INTERNAL_BIT, TRACE_INTERNAL_NMI_BIT, TRACE_INTERNAL_IRQ_BIT, @@ -449,9 +459,6 @@ enum { #define TRACE_FTRACE_START TRACE_FTRACE_BIT #define TRACE_FTRACE_MAX ((1 << (TRACE_FTRACE_START + TRACE_CONTEXT_BITS)) - 1) -#define TRACE_GLOBAL_START TRACE_GLOBAL_BIT -#define TRACE_GLOBAL_MAX ((1 << (TRACE_GLOBAL_START + TRACE_CONTEXT_BITS)) - 1) - #define TRACE_LIST_START TRACE_INTERNAL_BIT #define TRACE_LIST_MAX ((1 << (TRACE_LIST_START + TRACE_CONTEXT_BITS)) - 1) @@ -560,8 +567,6 @@ void trace_init_global_iter(struct trace_iterator *iter); void tracing_iter_reset(struct trace_iterator *iter, int cpu); -void poll_wait_pipe(struct trace_iterator *iter); - void tracing_sched_switch_trace(struct trace_array *tr, struct task_struct *prev, struct task_struct *next, @@ -608,8 +613,6 @@ extern unsigned long nsecs_to_usecs(unsigned long nsecs); extern unsigned long tracing_thresh; #ifdef CONFIG_TRACER_MAX_TRACE -extern unsigned long tracing_max_latency; - void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu); void update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu); @@ -724,6 +727,8 @@ extern unsigned long trace_flags; #define TRACE_GRAPH_PRINT_PROC 0x8 #define TRACE_GRAPH_PRINT_DURATION 0x10 #define TRACE_GRAPH_PRINT_ABS_TIME 0x20 +#define TRACE_GRAPH_PRINT_IRQS 0x40 +#define TRACE_GRAPH_PRINT_TAIL 0x80 #define TRACE_GRAPH_PRINT_FILL_SHIFT 28 #define TRACE_GRAPH_PRINT_FILL_MASK (0x3 << TRACE_GRAPH_PRINT_FILL_SHIFT) @@ -823,6 +828,10 @@ extern int ftrace_is_dead(void); int ftrace_create_function_files(struct trace_array *tr, struct dentry *parent); void ftrace_destroy_function_files(struct trace_array *tr); +void ftrace_init_global_array_ops(struct trace_array *tr); +void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func); +void ftrace_reset_array_ops(struct trace_array *tr); +int using_ftrace_ops_list_func(void); #else static inline int ftrace_trace_task(struct task_struct *task) { @@ -836,6 +845,11 @@ ftrace_create_function_files(struct trace_array *tr, return 0; } static inline void ftrace_destroy_function_files(struct trace_array *tr) { } +static inline __init void +ftrace_init_global_array_ops(struct trace_array *tr) { } +static inline void ftrace_reset_array_ops(struct trace_array *tr) { } +/* ftace_func_t type is not defined, use macro instead of static inline */ +#define ftrace_init_array_ops(tr, func) do { } while (0) #endif /* CONFIG_FUNCTION_TRACER */ #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE) diff --git a/kernel/trace/trace_benchmark.c b/kernel/trace/trace_benchmark.c new file mode 100644 index 00000000000..40a14cbcf8e --- /dev/null +++ b/kernel/trace/trace_benchmark.c @@ -0,0 +1,198 @@ +#include <linux/delay.h> +#include <linux/module.h> +#include <linux/kthread.h> +#include <linux/trace_clock.h> + +#define CREATE_TRACE_POINTS +#include "trace_benchmark.h" + +static struct task_struct *bm_event_thread; + +static char bm_str[BENCHMARK_EVENT_STRLEN] = "START"; + +static u64 bm_total; +static u64 bm_totalsq; +static u64 bm_last; +static u64 bm_max; +static u64 bm_min; +static u64 bm_first; +static u64 bm_cnt; +static u64 bm_stddev; +static unsigned int bm_avg; +static unsigned int bm_std; + +/* + * This gets called in a loop recording the time it took to write + * the tracepoint. What it writes is the time statistics of the last + * tracepoint write. As there is nothing to write the first time + * it simply writes "START". As the first write is cold cache and + * the rest is hot, we save off that time in bm_first and it is + * reported as "first", which is shown in the second write to the + * tracepoint. The "first" field is writen within the statics from + * then on but never changes. + */ +static void trace_do_benchmark(void) +{ + u64 start; + u64 stop; + u64 delta; + u64 stddev; + u64 seed; + u64 last_seed; + unsigned int avg; + unsigned int std = 0; + + /* Only run if the tracepoint is actually active */ + if (!trace_benchmark_event_enabled()) + return; + + local_irq_disable(); + start = trace_clock_local(); + trace_benchmark_event(bm_str); + stop = trace_clock_local(); + local_irq_enable(); + + bm_cnt++; + + delta = stop - start; + + /* + * The first read is cold cached, keep it separate from the + * other calculations. + */ + if (bm_cnt == 1) { + bm_first = delta; + scnprintf(bm_str, BENCHMARK_EVENT_STRLEN, + "first=%llu [COLD CACHED]", bm_first); + return; + } + + bm_last = delta; + + if (delta > bm_max) + bm_max = delta; + if (!bm_min || delta < bm_min) + bm_min = delta; + + /* + * When bm_cnt is greater than UINT_MAX, it breaks the statistics + * accounting. Freeze the statistics when that happens. + * We should have enough data for the avg and stddev anyway. + */ + if (bm_cnt > UINT_MAX) { + scnprintf(bm_str, BENCHMARK_EVENT_STRLEN, + "last=%llu first=%llu max=%llu min=%llu ** avg=%u std=%d std^2=%lld", + bm_last, bm_first, bm_max, bm_min, bm_avg, bm_std, bm_stddev); + return; + } + + bm_total += delta; + bm_totalsq += delta * delta; + + + if (bm_cnt > 1) { + /* + * Apply Welford's method to calculate standard deviation: + * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2) + */ + stddev = (u64)bm_cnt * bm_totalsq - bm_total * bm_total; + do_div(stddev, (u32)bm_cnt); + do_div(stddev, (u32)bm_cnt - 1); + } else + stddev = 0; + + delta = bm_total; + do_div(delta, bm_cnt); + avg = delta; + + if (stddev > 0) { + int i = 0; + /* + * stddev is the square of standard deviation but + * we want the actualy number. Use the average + * as our seed to find the std. + * + * The next try is: + * x = (x + N/x) / 2 + * + * Where N is the squared number to find the square + * root of. + */ + seed = avg; + do { + last_seed = seed; + seed = stddev; + if (!last_seed) + break; + do_div(seed, last_seed); + seed += last_seed; + do_div(seed, 2); + } while (i++ < 10 && last_seed != seed); + + std = seed; + } + + scnprintf(bm_str, BENCHMARK_EVENT_STRLEN, + "last=%llu first=%llu max=%llu min=%llu avg=%u std=%d std^2=%lld", + bm_last, bm_first, bm_max, bm_min, avg, std, stddev); + + bm_std = std; + bm_avg = avg; + bm_stddev = stddev; +} + +static int benchmark_event_kthread(void *arg) +{ + /* sleep a bit to make sure the tracepoint gets activated */ + msleep(100); + + while (!kthread_should_stop()) { + + trace_do_benchmark(); + + /* + * We don't go to sleep, but let others + * run as well. + */ + cond_resched(); + } + + return 0; +} + +/* + * When the benchmark tracepoint is enabled, it calls this + * function and the thread that calls the tracepoint is created. + */ +void trace_benchmark_reg(void) +{ + bm_event_thread = kthread_run(benchmark_event_kthread, + NULL, "event_benchmark"); + WARN_ON(!bm_event_thread); +} + +/* + * When the benchmark tracepoint is disabled, it calls this + * function and the thread that calls the tracepoint is deleted + * and all the numbers are reset. + */ +void trace_benchmark_unreg(void) +{ + if (!bm_event_thread) + return; + + kthread_stop(bm_event_thread); + + strcpy(bm_str, "START"); + bm_total = 0; + bm_totalsq = 0; + bm_last = 0; + bm_max = 0; + bm_min = 0; + bm_cnt = 0; + /* These don't need to be reset but reset them anyway */ + bm_first = 0; + bm_std = 0; + bm_avg = 0; + bm_stddev = 0; +} diff --git a/kernel/trace/trace_benchmark.h b/kernel/trace/trace_benchmark.h new file mode 100644 index 00000000000..3c1df1df4e2 --- /dev/null +++ b/kernel/trace/trace_benchmark.h @@ -0,0 +1,41 @@ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM benchmark + +#if !defined(_TRACE_BENCHMARK_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_BENCHMARK_H + +#include <linux/tracepoint.h> + +extern void trace_benchmark_reg(void); +extern void trace_benchmark_unreg(void); + +#define BENCHMARK_EVENT_STRLEN 128 + +TRACE_EVENT_FN(benchmark_event, + + TP_PROTO(const char *str), + + TP_ARGS(str), + + TP_STRUCT__entry( + __array( char, str, BENCHMARK_EVENT_STRLEN ) + ), + + TP_fast_assign( + memcpy(__entry->str, str, BENCHMARK_EVENT_STRLEN); + ), + + TP_printk("%s", __entry->str), + + trace_benchmark_reg, trace_benchmark_unreg +); + +#endif /* _TRACE_BENCHMARK_H */ + +#undef TRACE_INCLUDE_FILE +#undef TRACE_INCLUDE_PATH +#define TRACE_INCLUDE_PATH . +#define TRACE_INCLUDE_FILE trace_benchmark + +/* This part must be outside protection */ +#include <trace/define_trace.h> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 3ddfd8f62c0..f99e0b3bca8 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -574,6 +574,9 @@ int trace_set_clr_event(const char *system, const char *event, int set) { struct trace_array *tr = top_trace_array(); + if (!tr) + return -ENODEV; + return __ftrace_set_clr_event(tr, NULL, system, event, set); } EXPORT_SYMBOL_GPL(trace_set_clr_event); @@ -2065,6 +2068,9 @@ event_enable_func(struct ftrace_hash *hash, bool enable; int ret; + if (!tr) + return -ENODEV; + /* hash funcs only work with set_ftrace_filter */ if (!enabled || !param) return -EINVAL; @@ -2396,6 +2402,9 @@ static __init int event_trace_enable(void) char *token; int ret; + if (!tr) + return -ENODEV; + for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) { call = *iter; @@ -2442,6 +2451,8 @@ static __init int event_trace_init(void) int ret; tr = top_trace_array(); + if (!tr) + return -ENODEV; d_tracer = tracing_init_dentry(); if (!d_tracer) @@ -2535,6 +2546,8 @@ static __init void event_trace_self_tests(void) int ret; tr = top_trace_array(); + if (!tr) + return; pr_info("Running tests on trace events:\n"); diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c index ffd56351b52..57f0ec962d2 100644 --- a/kernel/trace/trace_functions.c +++ b/kernel/trace/trace_functions.c @@ -26,8 +26,6 @@ function_trace_call(unsigned long ip, unsigned long parent_ip, static void function_stack_trace_call(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *pt_regs); -static struct ftrace_ops trace_ops; -static struct ftrace_ops trace_stack_ops; static struct tracer_flags func_flags; /* Our option */ @@ -83,28 +81,24 @@ void ftrace_destroy_function_files(struct trace_array *tr) static int function_trace_init(struct trace_array *tr) { - struct ftrace_ops *ops; - - if (tr->flags & TRACE_ARRAY_FL_GLOBAL) { - /* There's only one global tr */ - if (!trace_ops.private) { - trace_ops.private = tr; - trace_stack_ops.private = tr; - } + ftrace_func_t func; - if (func_flags.val & TRACE_FUNC_OPT_STACK) - ops = &trace_stack_ops; - else - ops = &trace_ops; - tr->ops = ops; - } else if (!tr->ops) { - /* - * Instance trace_arrays get their ops allocated - * at instance creation. Unless it failed - * the allocation. - */ + /* + * Instance trace_arrays get their ops allocated + * at instance creation. Unless it failed + * the allocation. + */ + if (!tr->ops) return -ENOMEM; - } + + /* Currently only the global instance can do stack tracing */ + if (tr->flags & TRACE_ARRAY_FL_GLOBAL && + func_flags.val & TRACE_FUNC_OPT_STACK) + func = function_stack_trace_call; + else + func = function_trace_call; + + ftrace_init_array_ops(tr, func); tr->trace_buffer.cpu = get_cpu(); put_cpu(); @@ -118,6 +112,7 @@ static void function_trace_reset(struct trace_array *tr) { tracing_stop_function_trace(tr); tracing_stop_cmdline_record(); + ftrace_reset_array_ops(tr); } static void function_trace_start(struct trace_array *tr) @@ -199,18 +194,6 @@ function_stack_trace_call(unsigned long ip, unsigned long parent_ip, local_irq_restore(flags); } -static struct ftrace_ops trace_ops __read_mostly = -{ - .func = function_trace_call, - .flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE, -}; - -static struct ftrace_ops trace_stack_ops __read_mostly = -{ - .func = function_stack_trace_call, - .flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE, -}; - static struct tracer_opt func_opts[] = { #ifdef CONFIG_STACKTRACE { TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) }, @@ -248,10 +231,10 @@ func_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) unregister_ftrace_function(tr->ops); if (set) { - tr->ops = &trace_stack_ops; + tr->ops->func = function_stack_trace_call; register_ftrace_function(tr->ops); } else { - tr->ops = &trace_ops; + tr->ops->func = function_trace_call; register_ftrace_function(tr->ops); } @@ -269,7 +252,6 @@ static struct tracer function_trace __tracer_data = .init = function_trace_init, .reset = function_trace_reset, .start = function_trace_start, - .wait_pipe = poll_wait_pipe, .flags = &func_flags, .set_flag = func_set_flag, .allow_instances = true, diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index deff1120026..4de3e57f723 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -38,15 +38,6 @@ struct fgraph_data { #define TRACE_GRAPH_INDENT 2 -/* Flag options */ -#define TRACE_GRAPH_PRINT_OVERRUN 0x1 -#define TRACE_GRAPH_PRINT_CPU 0x2 -#define TRACE_GRAPH_PRINT_OVERHEAD 0x4 -#define TRACE_GRAPH_PRINT_PROC 0x8 -#define TRACE_GRAPH_PRINT_DURATION 0x10 -#define TRACE_GRAPH_PRINT_ABS_TIME 0x20 -#define TRACE_GRAPH_PRINT_IRQS 0x40 - static unsigned int max_depth; static struct tracer_opt trace_opts[] = { @@ -64,11 +55,13 @@ static struct tracer_opt trace_opts[] = { { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) }, /* Display interrupts */ { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) }, + /* Display function name after trailing } */ + { TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) }, { } /* Empty entry */ }; static struct tracer_flags tracer_flags = { - /* Don't display overruns and proc by default */ + /* Don't display overruns, proc, or tail by default */ .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD | TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS, .opts = trace_opts @@ -1176,9 +1169,10 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, * If the return function does not have a matching entry, * then the entry was lost. Instead of just printing * the '}' and letting the user guess what function this - * belongs to, write out the function name. + * belongs to, write out the function name. Always do + * that if the funcgraph-tail option is enabled. */ - if (func_match) { + if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL)) { ret = trace_seq_puts(s, "}\n"); if (!ret) return TRACE_TYPE_PARTIAL_LINE; @@ -1505,7 +1499,6 @@ static struct tracer graph_trace __tracer_data = { .pipe_open = graph_trace_open, .close = graph_trace_close, .pipe_close = graph_trace_close, - .wait_pipe = poll_wait_pipe, .init = graph_trace_init, .reset = graph_trace_reset, .print_line = print_graph_function, diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index 8ff02cbb892..9bb104f748d 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -151,12 +151,6 @@ irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip, atomic_dec(&data->disabled); } - -static struct ftrace_ops trace_ops __read_mostly = -{ - .func = irqsoff_tracer_call, - .flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE, -}; #endif /* CONFIG_FUNCTION_TRACER */ #ifdef CONFIG_FUNCTION_GRAPH_TRACER @@ -176,7 +170,7 @@ irqsoff_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) for_each_possible_cpu(cpu) per_cpu(tracing_cpu, cpu) = 0; - tracing_max_latency = 0; + tr->max_latency = 0; tracing_reset_online_cpus(&irqsoff_trace->trace_buffer); return start_irqsoff_tracer(irqsoff_trace, set); @@ -303,13 +297,13 @@ static void irqsoff_print_header(struct seq_file *s) /* * Should this new latency be reported/recorded? */ -static int report_latency(cycle_t delta) +static int report_latency(struct trace_array *tr, cycle_t delta) { if (tracing_thresh) { if (delta < tracing_thresh) return 0; } else { - if (delta <= tracing_max_latency) + if (delta <= tr->max_latency) return 0; } return 1; @@ -333,13 +327,13 @@ check_critical_timing(struct trace_array *tr, pc = preempt_count(); - if (!report_latency(delta)) + if (!report_latency(tr, delta)) goto out; raw_spin_lock_irqsave(&max_trace_lock, flags); /* check if we are still the max latency */ - if (!report_latency(delta)) + if (!report_latency(tr, delta)) goto out_unlock; __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc); @@ -352,7 +346,7 @@ check_critical_timing(struct trace_array *tr, data->critical_end = parent_ip; if (likely(!is_tracing_stopped())) { - tracing_max_latency = delta; + tr->max_latency = delta; update_max_tr_single(tr, current, cpu); } @@ -531,7 +525,7 @@ void trace_preempt_off(unsigned long a0, unsigned long a1) } #endif /* CONFIG_PREEMPT_TRACER */ -static int register_irqsoff_function(int graph, int set) +static int register_irqsoff_function(struct trace_array *tr, int graph, int set) { int ret; @@ -543,7 +537,7 @@ static int register_irqsoff_function(int graph, int set) ret = register_ftrace_graph(&irqsoff_graph_return, &irqsoff_graph_entry); else - ret = register_ftrace_function(&trace_ops); + ret = register_ftrace_function(tr->ops); if (!ret) function_enabled = true; @@ -551,7 +545,7 @@ static int register_irqsoff_function(int graph, int set) return ret; } -static void unregister_irqsoff_function(int graph) +static void unregister_irqsoff_function(struct trace_array *tr, int graph) { if (!function_enabled) return; @@ -559,17 +553,17 @@ static void unregister_irqsoff_function(int graph) if (graph) unregister_ftrace_graph(); else - unregister_ftrace_function(&trace_ops); + unregister_ftrace_function(tr->ops); function_enabled = false; } -static void irqsoff_function_set(int set) +static void irqsoff_function_set(struct trace_array *tr, int set) { if (set) - register_irqsoff_function(is_graph(), 1); + register_irqsoff_function(tr, is_graph(), 1); else - unregister_irqsoff_function(is_graph()); + unregister_irqsoff_function(tr, is_graph()); } static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set) @@ -577,7 +571,7 @@ static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set) struct tracer *tracer = tr->current_trace; if (mask & TRACE_ITER_FUNCTION) - irqsoff_function_set(set); + irqsoff_function_set(tr, set); return trace_keep_overwrite(tracer, mask, set); } @@ -586,7 +580,7 @@ static int start_irqsoff_tracer(struct trace_array *tr, int graph) { int ret; - ret = register_irqsoff_function(graph, 0); + ret = register_irqsoff_function(tr, graph, 0); if (!ret && tracing_is_enabled()) tracer_enabled = 1; @@ -600,25 +594,37 @@ static void stop_irqsoff_tracer(struct trace_array *tr, int graph) { tracer_enabled = 0; - unregister_irqsoff_function(graph); + unregister_irqsoff_function(tr, graph); } -static void __irqsoff_tracer_init(struct trace_array *tr) +static bool irqsoff_busy; + +static int __irqsoff_tracer_init(struct trace_array *tr) { + if (irqsoff_busy) + return -EBUSY; + save_flags = trace_flags; /* non overwrite screws up the latency tracers */ set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1); set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1); - tracing_max_latency = 0; + tr->max_latency = 0; irqsoff_trace = tr; /* make sure that the tracer is visible */ smp_wmb(); tracing_reset_online_cpus(&tr->trace_buffer); - if (start_irqsoff_tracer(tr, is_graph())) + ftrace_init_array_ops(tr, irqsoff_tracer_call); + + /* Only toplevel instance supports graph tracing */ + if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL && + is_graph()))) printk(KERN_ERR "failed to start irqsoff tracer\n"); + + irqsoff_busy = true; + return 0; } static void irqsoff_tracer_reset(struct trace_array *tr) @@ -630,6 +636,9 @@ static void irqsoff_tracer_reset(struct trace_array *tr) set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag); set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag); + ftrace_reset_array_ops(tr); + + irqsoff_busy = false; } static void irqsoff_tracer_start(struct trace_array *tr) @@ -647,8 +656,7 @@ static int irqsoff_tracer_init(struct trace_array *tr) { trace_type = TRACER_IRQS_OFF; - __irqsoff_tracer_init(tr); - return 0; + return __irqsoff_tracer_init(tr); } static struct tracer irqsoff_tracer __read_mostly = { @@ -668,6 +676,7 @@ static struct tracer irqsoff_tracer __read_mostly = #endif .open = irqsoff_trace_open, .close = irqsoff_trace_close, + .allow_instances = true, .use_max_tr = true, }; # define register_irqsoff(trace) register_tracer(&trace) @@ -680,8 +689,7 @@ static int preemptoff_tracer_init(struct trace_array *tr) { trace_type = TRACER_PREEMPT_OFF; - __irqsoff_tracer_init(tr); - return 0; + return __irqsoff_tracer_init(tr); } static struct tracer preemptoff_tracer __read_mostly = @@ -702,6 +710,7 @@ static struct tracer preemptoff_tracer __read_mostly = #endif .open = irqsoff_trace_open, .close = irqsoff_trace_close, + .allow_instances = true, .use_max_tr = true, }; # define register_preemptoff(trace) register_tracer(&trace) @@ -716,8 +725,7 @@ static int preemptirqsoff_tracer_init(struct trace_array *tr) { trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF; - __irqsoff_tracer_init(tr); - return 0; + return __irqsoff_tracer_init(tr); } static struct tracer preemptirqsoff_tracer __read_mostly = @@ -738,6 +746,7 @@ static struct tracer preemptirqsoff_tracer __read_mostly = #endif .open = irqsoff_trace_open, .close = irqsoff_trace_close, + .allow_instances = true, .use_max_tr = true, }; diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 903ae28962b..ef2fba1f46b 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1377,6 +1377,9 @@ static __init int kprobe_trace_self_tests_init(void) struct trace_kprobe *tk; struct ftrace_event_file *file; + if (tracing_is_disabled()) + return -ENODEV; + target = kprobe_trace_selftest_target; pr_info("Testing kprobe tracing: "); diff --git a/kernel/trace/trace_nop.c b/kernel/trace/trace_nop.c index 69a5cc94c01..fcf0a9e4891 100644 --- a/kernel/trace/trace_nop.c +++ b/kernel/trace/trace_nop.c @@ -91,7 +91,6 @@ struct tracer nop_trace __read_mostly = .name = "nop", .init = nop_trace_init, .reset = nop_trace_reset, - .wait_pipe = poll_wait_pipe, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_nop, #endif diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index a436de18aa9..f3dad80c20b 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -126,6 +126,34 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...) EXPORT_SYMBOL_GPL(trace_seq_printf); /** + * trace_seq_bitmask - put a list of longs as a bitmask print output + * @s: trace sequence descriptor + * @maskp: points to an array of unsigned longs that represent a bitmask + * @nmaskbits: The number of bits that are valid in @maskp + * + * It returns 0 if the trace oversizes the buffer's free + * space, 1 otherwise. + * + * Writes a ASCII representation of a bitmask string into @s. + */ +int +trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, + int nmaskbits) +{ + int len = (PAGE_SIZE - 1) - s->len; + int ret; + + if (s->full || !len) + return 0; + + ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits); + s->len += ret; + + return 1; +} +EXPORT_SYMBOL_GPL(trace_seq_bitmask); + +/** * trace_seq_vprintf - sequence printing of trace information * @s: trace sequence descriptor * @fmt: printf format string @@ -399,6 +427,19 @@ EXPORT_SYMBOL(ftrace_print_symbols_seq_u64); #endif const char * +ftrace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr, + unsigned int bitmask_size) +{ + const char *ret = p->buffer + p->len; + + trace_seq_bitmask(p, bitmask_ptr, bitmask_size * 8); + trace_seq_putc(p, 0); + + return ret; +} +EXPORT_SYMBOL_GPL(ftrace_print_bitmask_seq); + +const char * ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len) { int i; diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index e14da5e97a6..19bd8928ce9 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -130,15 +130,9 @@ wakeup_tracer_call(unsigned long ip, unsigned long parent_ip, atomic_dec(&data->disabled); preempt_enable_notrace(); } - -static struct ftrace_ops trace_ops __read_mostly = -{ - .func = wakeup_tracer_call, - .flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE, -}; #endif /* CONFIG_FUNCTION_TRACER */ -static int register_wakeup_function(int graph, int set) +static int register_wakeup_function(struct trace_array *tr, int graph, int set) { int ret; @@ -150,7 +144,7 @@ static int register_wakeup_function(int graph, int set) ret = register_ftrace_graph(&wakeup_graph_return, &wakeup_graph_entry); else - ret = register_ftrace_function(&trace_ops); + ret = register_ftrace_function(tr->ops); if (!ret) function_enabled = true; @@ -158,7 +152,7 @@ static int register_wakeup_function(int graph, int set) return ret; } -static void unregister_wakeup_function(int graph) +static void unregister_wakeup_function(struct trace_array *tr, int graph) { if (!function_enabled) return; @@ -166,17 +160,17 @@ static void unregister_wakeup_function(int graph) if (graph) unregister_ftrace_graph(); else - unregister_ftrace_function(&trace_ops); + unregister_ftrace_function(tr->ops); function_enabled = false; } -static void wakeup_function_set(int set) +static void wakeup_function_set(struct trace_array *tr, int set) { if (set) - register_wakeup_function(is_graph(), 1); + register_wakeup_function(tr, is_graph(), 1); else - unregister_wakeup_function(is_graph()); + unregister_wakeup_function(tr, is_graph()); } static int wakeup_flag_changed(struct trace_array *tr, u32 mask, int set) @@ -184,16 +178,16 @@ static int wakeup_flag_changed(struct trace_array *tr, u32 mask, int set) struct tracer *tracer = tr->current_trace; if (mask & TRACE_ITER_FUNCTION) - wakeup_function_set(set); + wakeup_function_set(tr, set); return trace_keep_overwrite(tracer, mask, set); } -static int start_func_tracer(int graph) +static int start_func_tracer(struct trace_array *tr, int graph) { int ret; - ret = register_wakeup_function(graph, 0); + ret = register_wakeup_function(tr, graph, 0); if (!ret && tracing_is_enabled()) tracer_enabled = 1; @@ -203,11 +197,11 @@ static int start_func_tracer(int graph) return ret; } -static void stop_func_tracer(int graph) +static void stop_func_tracer(struct trace_array *tr, int graph) { tracer_enabled = 0; - unregister_wakeup_function(graph); + unregister_wakeup_function(tr, graph); } #ifdef CONFIG_FUNCTION_GRAPH_TRACER @@ -221,12 +215,12 @@ wakeup_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) if (!(is_graph() ^ set)) return 0; - stop_func_tracer(!set); + stop_func_tracer(tr, !set); wakeup_reset(wakeup_trace); - tracing_max_latency = 0; + tr->max_latency = 0; - return start_func_tracer(set); + return start_func_tracer(tr, set); } static int wakeup_graph_entry(struct ftrace_graph_ent *trace) @@ -350,13 +344,13 @@ static void wakeup_print_header(struct seq_file *s) /* * Should this new latency be reported/recorded? */ -static int report_latency(cycle_t delta) +static int report_latency(struct trace_array *tr, cycle_t delta) { if (tracing_thresh) { if (delta < tracing_thresh) return 0; } else { - if (delta <= tracing_max_latency) + if (delta <= tr->max_latency) return 0; } return 1; @@ -424,11 +418,11 @@ probe_wakeup_sched_switch(void *ignore, T1 = ftrace_now(cpu); delta = T1-T0; - if (!report_latency(delta)) + if (!report_latency(wakeup_trace, delta)) goto out_unlock; if (likely(!is_tracing_stopped())) { - tracing_max_latency = delta; + wakeup_trace->max_latency = delta; update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu); } @@ -587,7 +581,7 @@ static void start_wakeup_tracer(struct trace_array *tr) */ smp_wmb(); - if (start_func_tracer(is_graph())) + if (start_func_tracer(tr, is_graph())) printk(KERN_ERR "failed to start wakeup tracer\n"); return; @@ -600,13 +594,15 @@ fail_deprobe: static void stop_wakeup_tracer(struct trace_array *tr) { tracer_enabled = 0; - stop_func_tracer(is_graph()); + stop_func_tracer(tr, is_graph()); unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL); unregister_trace_sched_wakeup_new(probe_wakeup, NULL); unregister_trace_sched_wakeup(probe_wakeup, NULL); unregister_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL); } +static bool wakeup_busy; + static int __wakeup_tracer_init(struct trace_array *tr) { save_flags = trace_flags; @@ -615,14 +611,20 @@ static int __wakeup_tracer_init(struct trace_array *tr) set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1); set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1); - tracing_max_latency = 0; + tr->max_latency = 0; wakeup_trace = tr; + ftrace_init_array_ops(tr, wakeup_tracer_call); start_wakeup_tracer(tr); + + wakeup_busy = true; return 0; } static int wakeup_tracer_init(struct trace_array *tr) { + if (wakeup_busy) + return -EBUSY; + wakeup_dl = 0; wakeup_rt = 0; return __wakeup_tracer_init(tr); @@ -630,6 +632,9 @@ static int wakeup_tracer_init(struct trace_array *tr) static int wakeup_rt_tracer_init(struct trace_array *tr) { + if (wakeup_busy) + return -EBUSY; + wakeup_dl = 0; wakeup_rt = 1; return __wakeup_tracer_init(tr); @@ -637,6 +642,9 @@ static int wakeup_rt_tracer_init(struct trace_array *tr) static int wakeup_dl_tracer_init(struct trace_array *tr) { + if (wakeup_busy) + return -EBUSY; + wakeup_dl = 1; wakeup_rt = 0; return __wakeup_tracer_init(tr); @@ -653,6 +661,8 @@ static void wakeup_tracer_reset(struct trace_array *tr) set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag); set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag); + ftrace_reset_array_ops(tr); + wakeup_busy = false; } static void wakeup_tracer_start(struct trace_array *tr) @@ -684,6 +694,7 @@ static struct tracer wakeup_tracer __read_mostly = #endif .open = wakeup_trace_open, .close = wakeup_trace_close, + .allow_instances = true, .use_max_tr = true, }; @@ -694,7 +705,6 @@ static struct tracer wakeup_rt_tracer __read_mostly = .reset = wakeup_tracer_reset, .start = wakeup_tracer_start, .stop = wakeup_tracer_stop, - .wait_pipe = poll_wait_pipe, .print_max = true, .print_header = wakeup_print_header, .print_line = wakeup_print_line, @@ -706,6 +716,7 @@ static struct tracer wakeup_rt_tracer __read_mostly = #endif .open = wakeup_trace_open, .close = wakeup_trace_close, + .allow_instances = true, .use_max_tr = true, }; @@ -716,7 +727,6 @@ static struct tracer wakeup_dl_tracer __read_mostly = .reset = wakeup_tracer_reset, .start = wakeup_tracer_start, .stop = wakeup_tracer_stop, - .wait_pipe = poll_wait_pipe, .print_max = true, .print_header = wakeup_print_header, .print_line = wakeup_print_line, diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index e98fca60974..5ef60499dc8 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -65,7 +65,7 @@ static int trace_test_buffer(struct trace_buffer *buf, unsigned long *count) /* Don't allow flipping of max traces now */ local_irq_save(flags); - arch_spin_lock(&ftrace_max_lock); + arch_spin_lock(&buf->tr->max_lock); cnt = ring_buffer_entries(buf->buffer); @@ -83,7 +83,7 @@ static int trace_test_buffer(struct trace_buffer *buf, unsigned long *count) break; } tracing_on(); - arch_spin_unlock(&ftrace_max_lock); + arch_spin_unlock(&buf->tr->max_lock); local_irq_restore(flags); if (count) @@ -161,11 +161,6 @@ static struct ftrace_ops test_probe3 = { .flags = FTRACE_OPS_FL_RECURSION_SAFE, }; -static struct ftrace_ops test_global = { - .func = trace_selftest_test_global_func, - .flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE, -}; - static void print_counts(void) { printk("(%d %d %d %d %d) ", @@ -185,7 +180,7 @@ static void reset_counts(void) trace_selftest_test_dyn_cnt = 0; } -static int trace_selftest_ops(int cnt) +static int trace_selftest_ops(struct trace_array *tr, int cnt) { int save_ftrace_enabled = ftrace_enabled; struct ftrace_ops *dyn_ops; @@ -220,7 +215,11 @@ static int trace_selftest_ops(int cnt) register_ftrace_function(&test_probe1); register_ftrace_function(&test_probe2); register_ftrace_function(&test_probe3); - register_ftrace_function(&test_global); + /* First time we are running with main function */ + if (cnt > 1) { + ftrace_init_array_ops(tr, trace_selftest_test_global_func); + register_ftrace_function(tr->ops); + } DYN_FTRACE_TEST_NAME(); @@ -232,8 +231,10 @@ static int trace_selftest_ops(int cnt) goto out; if (trace_selftest_test_probe3_cnt != 1) goto out; - if (trace_selftest_test_global_cnt == 0) - goto out; + if (cnt > 1) { + if (trace_selftest_test_global_cnt == 0) + goto out; + } DYN_FTRACE_TEST_NAME2(); @@ -269,8 +270,10 @@ static int trace_selftest_ops(int cnt) goto out_free; if (trace_selftest_test_probe3_cnt != 3) goto out_free; - if (trace_selftest_test_global_cnt == 0) - goto out; + if (cnt > 1) { + if (trace_selftest_test_global_cnt == 0) + goto out; + } if (trace_selftest_test_dyn_cnt == 0) goto out_free; @@ -295,7 +298,9 @@ static int trace_selftest_ops(int cnt) unregister_ftrace_function(&test_probe1); unregister_ftrace_function(&test_probe2); unregister_ftrace_function(&test_probe3); - unregister_ftrace_function(&test_global); + if (cnt > 1) + unregister_ftrace_function(tr->ops); + ftrace_reset_array_ops(tr); /* Make sure everything is off */ reset_counts(); @@ -315,9 +320,9 @@ static int trace_selftest_ops(int cnt) } /* Test dynamic code modification and ftrace filters */ -int trace_selftest_startup_dynamic_tracing(struct tracer *trace, - struct trace_array *tr, - int (*func)(void)) +static int trace_selftest_startup_dynamic_tracing(struct tracer *trace, + struct trace_array *tr, + int (*func)(void)) { int save_ftrace_enabled = ftrace_enabled; unsigned long count; @@ -388,7 +393,7 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace, } /* Test the ops with global tracing running */ - ret = trace_selftest_ops(1); + ret = trace_selftest_ops(tr, 1); trace->reset(tr); out: @@ -399,7 +404,7 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace, /* Test the ops with global tracing off */ if (!ret) - ret = trace_selftest_ops(2); + ret = trace_selftest_ops(tr, 2); return ret; } @@ -802,7 +807,7 @@ out: int trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr) { - unsigned long save_max = tracing_max_latency; + unsigned long save_max = tr->max_latency; unsigned long count; int ret; @@ -814,7 +819,7 @@ trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr) } /* reset the max latency */ - tracing_max_latency = 0; + tr->max_latency = 0; /* disable interrupts for a bit */ local_irq_disable(); udelay(100); @@ -841,7 +846,7 @@ trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr) ret = -1; } - tracing_max_latency = save_max; + tr->max_latency = save_max; return ret; } @@ -851,7 +856,7 @@ trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr) int trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr) { - unsigned long save_max = tracing_max_latency; + unsigned long save_max = tr->max_latency; unsigned long count; int ret; @@ -876,7 +881,7 @@ trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr) } /* reset the max latency */ - tracing_max_latency = 0; + tr->max_latency = 0; /* disable preemption for a bit */ preempt_disable(); udelay(100); @@ -903,7 +908,7 @@ trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr) ret = -1; } - tracing_max_latency = save_max; + tr->max_latency = save_max; return ret; } @@ -913,7 +918,7 @@ trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr) int trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *tr) { - unsigned long save_max = tracing_max_latency; + unsigned long save_max = tr->max_latency; unsigned long count; int ret; @@ -938,7 +943,7 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array * } /* reset the max latency */ - tracing_max_latency = 0; + tr->max_latency = 0; /* disable preemption and interrupts for a bit */ preempt_disable(); @@ -973,7 +978,7 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array * } /* do the test by disabling interrupts first this time */ - tracing_max_latency = 0; + tr->max_latency = 0; tracing_start(); trace->start(tr); @@ -1004,7 +1009,7 @@ out: tracing_start(); out_no_start: trace->reset(tr); - tracing_max_latency = save_max; + tr->max_latency = save_max; return ret; } @@ -1057,7 +1062,7 @@ static int trace_wakeup_test_thread(void *data) int trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr) { - unsigned long save_max = tracing_max_latency; + unsigned long save_max = tr->max_latency; struct task_struct *p; struct completion is_ready; unsigned long count; @@ -1083,7 +1088,7 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr) } /* reset the max latency */ - tracing_max_latency = 0; + tr->max_latency = 0; while (p->on_rq) { /* @@ -1113,7 +1118,7 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr) trace->reset(tr); tracing_start(); - tracing_max_latency = save_max; + tr->max_latency = save_max; /* kill the thread */ kthread_stop(p); diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 21b320e5d16..8a4e5cb66a4 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -51,11 +51,33 @@ static DEFINE_MUTEX(stack_sysctl_mutex); int stack_tracer_enabled; static int last_stack_tracer_enabled; +static inline void print_max_stack(void) +{ + long i; + int size; + + pr_emerg(" Depth Size Location (%d entries)\n" + " ----- ---- --------\n", + max_stack_trace.nr_entries - 1); + + for (i = 0; i < max_stack_trace.nr_entries; i++) { + if (stack_dump_trace[i] == ULONG_MAX) + break; + if (i+1 == max_stack_trace.nr_entries || + stack_dump_trace[i+1] == ULONG_MAX) + size = stack_dump_index[i]; + else + size = stack_dump_index[i] - stack_dump_index[i+1]; + + pr_emerg("%3ld) %8d %5d %pS\n", i, stack_dump_index[i], + size, (void *)stack_dump_trace[i]); + } +} + static inline void check_stack(unsigned long ip, unsigned long *stack) { - unsigned long this_size, flags; - unsigned long *p, *top, *start; + unsigned long this_size, flags; unsigned long *p, *top, *start; static int tracer_frame; int frame_size = ACCESS_ONCE(tracer_frame); int i; @@ -85,8 +107,12 @@ check_stack(unsigned long ip, unsigned long *stack) max_stack_size = this_size; - max_stack_trace.nr_entries = 0; - max_stack_trace.skip = 3; + max_stack_trace.nr_entries = 0; + + if (using_ftrace_ops_list_func()) + max_stack_trace.skip = 4; + else + max_stack_trace.skip = 3; save_stack_trace(&max_stack_trace); @@ -145,8 +171,12 @@ check_stack(unsigned long ip, unsigned long *stack) i++; } - BUG_ON(current != &init_task && - *(end_of_stack(current)) != STACK_END_MAGIC); + if ((current != &init_task && + *(end_of_stack(current)) != STACK_END_MAGIC)) { + print_max_stack(); + BUG(); + } + out: arch_spin_unlock(&max_stack_lock); local_irq_restore(flags); |