diff options
| -rw-r--r-- | include/linux/ftrace.h | 1 | ||||
| -rw-r--r-- | include/linux/kernel.h | 1 | ||||
| -rw-r--r-- | kernel/extable.c | 8 | ||||
| -rw-r--r-- | kernel/trace/ftrace.c | 37 |
4 files changed, 40 insertions, 7 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 4609c0ece79..caba694a62b 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -34,6 +34,7 @@ struct ftrace_hash; enum { FTRACE_OPS_FL_ENABLED = 1 << 0, FTRACE_OPS_FL_GLOBAL = 1 << 1, + FTRACE_OPS_FL_DYNAMIC = 1 << 2, }; struct ftrace_ops { diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 00cec4dc0ae..f37ba716ef8 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -283,6 +283,7 @@ extern char *get_options(const char *str, int nints, int *ints); extern unsigned long long memparse(const char *ptr, char **retptr); extern int core_kernel_text(unsigned long addr); +extern int core_kernel_data(unsigned long addr); extern int __kernel_text_address(unsigned long addr); extern int kernel_text_address(unsigned long addr); extern int func_ptr_is_kernel_text(void *ptr); diff --git a/kernel/extable.c b/kernel/extable.c index 7f8f263f852..c2d625fcda7 100644 --- a/kernel/extable.c +++ b/kernel/extable.c @@ -72,6 +72,14 @@ int core_kernel_text(unsigned long addr) return 0; } +int core_kernel_data(unsigned long addr) +{ + if (addr >= (unsigned long)_sdata && + addr < (unsigned long)_edata) + return 1; + return 0; +} + int __kernel_text_address(unsigned long addr) { if (core_kernel_text(addr)) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 6c7e1df39b5..5b3ee04e39d 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -189,8 +189,14 @@ static void update_ftrace_function(void) update_global_ops(); + /* + * If we are at the end of the list and this ops is + * not dynamic, then have the mcount trampoline call + * the function directly + */ if (ftrace_ops_list == &ftrace_list_end || - ftrace_ops_list->next == &ftrace_list_end) + (ftrace_ops_list->next == &ftrace_list_end && + !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC))) func = ftrace_ops_list->func; else func = ftrace_ops_list_func; @@ -250,6 +256,9 @@ static int __register_ftrace_function(struct ftrace_ops *ops) if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED)) return -EBUSY; + if (!core_kernel_data((unsigned long)ops)) + ops->flags |= FTRACE_OPS_FL_DYNAMIC; + if (ops->flags & FTRACE_OPS_FL_GLOBAL) { int first = ftrace_global_list == &ftrace_list_end; add_ftrace_ops(&ftrace_global_list, ops); @@ -293,6 +302,13 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops) if (ftrace_enabled) update_ftrace_function(); + /* + * Dynamic ops may be freed, we must make sure that all + * callers are done before leaving this function. + */ + if (ops->flags & FTRACE_OPS_FL_DYNAMIC) + synchronize_sched(); + return 0; } @@ -1225,6 +1241,9 @@ ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src) * the filter_hash does not exist or is empty, * AND * the ip is not in the ops->notrace_hash. + * + * This needs to be called with preemption disabled as + * the hashes are freed with call_rcu_sched(). */ static int ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip) @@ -1233,9 +1252,6 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip) struct ftrace_hash *notrace_hash; int ret; - /* The hashes are freed with call_rcu_sched() */ - preempt_disable_notrace(); - filter_hash = rcu_dereference_raw(ops->filter_hash); notrace_hash = rcu_dereference_raw(ops->notrace_hash); @@ -1246,7 +1262,6 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip) ret = 1; else ret = 0; - preempt_enable_notrace(); return ret; } @@ -3425,14 +3440,20 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip) static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip) { - /* see comment above ftrace_global_list_func */ - struct ftrace_ops *op = rcu_dereference_raw(ftrace_ops_list); + struct ftrace_ops *op; + /* + * Some of the ops may be dynamically allocated, + * they must be freed after a synchronize_sched(). + */ + preempt_disable_notrace(); + op = rcu_dereference_raw(ftrace_ops_list); while (op != &ftrace_list_end) { if (ftrace_ops_test(op, ip)) op->func(ip, parent_ip); op = rcu_dereference_raw(op->next); }; + preempt_enable_notrace(); } static void clear_ftrace_swapper(void) @@ -3743,6 +3764,7 @@ int register_ftrace_function(struct ftrace_ops *ops) mutex_unlock(&ftrace_lock); return ret; } +EXPORT_SYMBOL_GPL(register_ftrace_function); /** * unregister_ftrace_function - unregister a function for profiling. @@ -3762,6 +3784,7 @@ int unregister_ftrace_function(struct ftrace_ops *ops) return ret; } +EXPORT_SYMBOL_GPL(unregister_ftrace_function); int ftrace_enable_sysctl(struct ctl_table *table, int write, |