From 238ae93d699d59876b470bf6455de22bcfaa9a1b Mon Sep 17 00:00:00 2001 From: Wang YanQing Date: Sun, 26 May 2013 16:52:01 +0800 Subject: tracing: Fix file mode of free_buffer Commit 4f271a2a60c748599b30bb4dafff30d770439b96 (tracing: Add a proc file to stop tracing and free buffer) implement a method to free up ring buffer in kernel memory in the release code path of free_buffer's fd. Then we don't need read/write support for free_buffer, indeed we just have a dummy write fop, and don't implement read fop. So the 0200 is more reasonable file mode for free_buffer than the current file mode 0644. Link: http://lkml.kernel.org/r/20130526085201.GA3183@udknight Acked-by: Vaibhav Nagarnaik Acked-by: David Sharp Signed-off-by: Wang YanQing Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 1a41023a1f8..5f4a09c12e0 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5935,7 +5935,7 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer) trace_create_file("buffer_total_size_kb", 0444, d_tracer, tr, &tracing_total_entries_fops); - trace_create_file("free_buffer", 0644, d_tracer, + trace_create_file("free_buffer", 0200, d_tracer, tr, &tracing_free_buffer_fops); trace_create_file("trace_marker", 0220, d_tracer, -- cgit v1.2.3-70-g09d2 From de7edd31457b626e54a0b2a7e8ff4d65492f01ad Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Fri, 14 Jun 2013 16:21:43 -0400 Subject: tracing: Disable tracing on warning Add a traceoff_on_warning option in both the kernel command line as well as a sysctl option. When set, any WARN*() function that is hit will cause the tracing_on variable to be cleared, which disables writing to the ring buffer. This is useful especially when tracing a bug with function tracing. When a warning is hit, the print caused by the warning can flood the trace with the functions that producing the output for the warning. This can make the resulting trace useless by either hiding where the bug happened, or worse, by overflowing the buffer and losing the trace of the bug totally. Acked-by: Peter Zijlstra Signed-off-by: Steven Rostedt --- Documentation/kernel-parameters.txt | 13 +++++++++++++ include/linux/ftrace.h | 5 +++++ kernel/panic.c | 3 +++ kernel/sysctl.c | 7 +++++++ kernel/trace/trace.c | 17 +++++++++++++++++ 5 files changed, 45 insertions(+) (limited to 'kernel/trace/trace.c') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 6e3b18a8afc..729d0b9803b 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -3069,6 +3069,19 @@ bytes respectively. Such letter suffixes can also be entirely omitted. See also Documentation/trace/ftrace.txt "trace options" section. + traceoff_on_warning + [FTRACE] enable this option to disable tracing when a + warning is hit. This turns off "tracing_on". Tracing can + be enabled again by echoing '1' into the "tracing_on" + file located in /sys/kernel/debug/tracing/ + + This option is useful, as it disables the trace before + the WARNING dump is called, which prevents the trace to + be filled with content caused by the warning output. + + This option can also be set at run time via the sysctl + option: kernel/traceoff_on_warning + transparent_hugepage= [KNL] Format: [always|madvise|never] diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index e48ed1d7876..9f15c0064c5 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -824,10 +824,15 @@ enum ftrace_dump_mode; extern enum ftrace_dump_mode ftrace_dump_on_oops; +extern void disable_trace_on_warning(void); +extern int __disable_trace_on_warning; + #ifdef CONFIG_PREEMPT #define INIT_TRACE_RECURSION .trace_recursion = 0, #endif +#else /* CONFIG_TRACING */ +static inline void disable_trace_on_warning(void) { } #endif /* CONFIG_TRACING */ #ifndef INIT_TRACE_RECURSION diff --git a/kernel/panic.c b/kernel/panic.c index 167ec097ce8..4cea6cc628a 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -399,6 +400,8 @@ struct slowpath_args { static void warn_slowpath_common(const char *file, int line, void *caller, unsigned taint, struct slowpath_args *args) { + disable_trace_on_warning(); + printk(KERN_WARNING "------------[ cut here ]------------\n"); printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller); diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 9edcf456e0f..5b0f18c1280 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -600,6 +600,13 @@ static struct ctl_table kern_table[] = { .mode = 0644, .proc_handler = proc_dointvec, }, + { + .procname = "traceoff_on_warning", + .data = &__disable_trace_on_warning, + .maxlen = sizeof(__disable_trace_on_warning), + .mode = 0644, + .proc_handler = proc_dointvec, + }, #endif #ifdef CONFIG_MODULES { diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 5f4a09c12e0..c4c9296b191 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -115,6 +115,9 @@ cpumask_var_t __read_mostly tracing_buffer_mask; enum ftrace_dump_mode ftrace_dump_on_oops; +/* When set, tracing will stop when a WARN*() is hit */ +int __disable_trace_on_warning; + static int tracing_set_tracer(const char *buf); #define MAX_TRACER_SIZE 100 @@ -149,6 +152,13 @@ static int __init set_ftrace_dump_on_oops(char *str) } __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops); +static int __init stop_trace_on_warning(char *str) +{ + __disable_trace_on_warning = 1; + return 1; +} +__setup("traceoff_on_warning=", stop_trace_on_warning); + static int __init boot_alloc_snapshot(char *str) { allocate_snapshot = true; @@ -170,6 +180,7 @@ static int __init set_trace_boot_options(char *str) } __setup("trace_options=", set_trace_boot_options); + unsigned long long ns2usecs(cycle_t nsec) { nsec += 500; @@ -562,6 +573,12 @@ void tracing_off(void) } EXPORT_SYMBOL_GPL(tracing_off); +void disable_trace_on_warning(void) +{ + if (__disable_trace_on_warning) + tracing_off(); +} + /** * tracing_is_on - show state of ring buffers enabled */ -- cgit v1.2.3-70-g09d2 From 10246fa35d4ffdfe472185d4cbf9c2dfd9a9f023 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Mon, 1 Jul 2013 15:58:24 -0400 Subject: tracing: Use flag buffer_disabled for irqsoff tracer If the ring buffer is disabled and the irqsoff tracer records a trace it will clear out its buffer and lose the data it had previously recorded. Currently there's a callback when writing to the tracing_of file, but if tracing is disabled via the function tracer trigger, it will not inform the irqsoff tracer to stop recording. By using the "mirror" flag (buffer_disabled) in the trace_array, that keeps track of the status of the trace_array's buffer, it gives the irqsoff tracer a fast way to know if it should record a new trace or not. The flag may be a little behind the real state of the buffer, but it should not affect the trace too much. It's more important for the irqsoff tracer to be fast. Reported-by: Dave Jones Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 101 ++++++++++++++++++++++++++++++------------- kernel/trace/trace_irqsoff.c | 4 +- 2 files changed, 72 insertions(+), 33 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index c4c9296b191..0dc50711d65 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -226,9 +226,24 @@ cycle_t ftrace_now(int cpu) return ts; } +/** + * tracing_is_enabled - Show if global_trace has been disabled + * + * Shows if the global trace has been enabled or not. It uses the + * mirror flag "buffer_disabled" to be used in fast paths such as for + * the irqsoff tracer. But it may be inaccurate due to races. If you + * need to know the accurate state, use tracing_is_on() which is a little + * slower, but accurate. + */ int tracing_is_enabled(void) { - return tracing_is_on(); + /* + * For quick access (irqsoff uses this in fast path), just + * return the mirror variable of the state of the ring buffer. + * It's a little racy, but we don't really care. + */ + smp_rmb(); + return !global_trace.buffer_disabled; } /* @@ -341,6 +356,23 @@ unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | TRACE_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS | TRACE_ITER_FUNCTION; +void tracer_tracing_on(struct trace_array *tr) +{ + if (tr->trace_buffer.buffer) + ring_buffer_record_on(tr->trace_buffer.buffer); + /* + * This flag is looked at when buffers haven't been allocated + * yet, or by some tracers (like irqsoff), that just want to + * know if the ring buffer has been disabled, but it can handle + * races of where it gets disabled but we still do a record. + * As the check is in the fast path of the tracers, it is more + * important to be fast than accurate. + */ + tr->buffer_disabled = 0; + /* Make the flag seen by readers */ + smp_wmb(); +} + /** * tracing_on - enable tracing buffers * @@ -349,15 +381,7 @@ unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | */ void tracing_on(void) { - if (global_trace.trace_buffer.buffer) - ring_buffer_record_on(global_trace.trace_buffer.buffer); - /* - * This flag is only looked at when buffers haven't been - * allocated yet. We don't really care about the race - * between setting this flag and actually turning - * on the buffer. - */ - global_trace.buffer_disabled = 0; + tracer_tracing_on(&global_trace); } EXPORT_SYMBOL_GPL(tracing_on); @@ -551,6 +575,23 @@ void tracing_snapshot_alloc(void) EXPORT_SYMBOL_GPL(tracing_snapshot_alloc); #endif /* CONFIG_TRACER_SNAPSHOT */ +void tracer_tracing_off(struct trace_array *tr) +{ + if (tr->trace_buffer.buffer) + ring_buffer_record_off(tr->trace_buffer.buffer); + /* + * This flag is looked at when buffers haven't been allocated + * yet, or by some tracers (like irqsoff), that just want to + * know if the ring buffer has been disabled, but it can handle + * races of where it gets disabled but we still do a record. + * As the check is in the fast path of the tracers, it is more + * important to be fast than accurate. + */ + tr->buffer_disabled = 1; + /* Make the flag seen by readers */ + smp_wmb(); +} + /** * tracing_off - turn off tracing buffers * @@ -561,15 +602,7 @@ EXPORT_SYMBOL_GPL(tracing_snapshot_alloc); */ void tracing_off(void) { - if (global_trace.trace_buffer.buffer) - ring_buffer_record_off(global_trace.trace_buffer.buffer); - /* - * This flag is only looked at when buffers haven't been - * allocated yet. We don't really care about the race - * between setting this flag and actually turning - * on the buffer. - */ - global_trace.buffer_disabled = 1; + tracer_tracing_off(&global_trace); } EXPORT_SYMBOL_GPL(tracing_off); @@ -579,14 +612,25 @@ void disable_trace_on_warning(void) tracing_off(); } +/** + * tracer_tracing_is_on - show real state of ring buffer enabled + * @tr : the trace array to know if ring buffer is enabled + * + * Shows real state of the ring buffer if it is enabled or not. + */ +int tracer_tracing_is_on(struct trace_array *tr) +{ + if (tr->trace_buffer.buffer) + return ring_buffer_record_is_on(tr->trace_buffer.buffer); + return !tr->buffer_disabled; +} + /** * tracing_is_on - show state of ring buffers enabled */ int tracing_is_on(void) { - if (global_trace.trace_buffer.buffer) - return ring_buffer_record_is_on(global_trace.trace_buffer.buffer); - return !global_trace.buffer_disabled; + return tracer_tracing_is_on(&global_trace); } EXPORT_SYMBOL_GPL(tracing_is_on); @@ -3958,7 +4002,7 @@ static int tracing_wait_pipe(struct file *filp) * * iter->pos will be 0 if we haven't read anything. */ - if (!tracing_is_enabled() && iter->pos) + if (!tracing_is_on() && iter->pos) break; } @@ -5631,15 +5675,10 @@ rb_simple_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { struct trace_array *tr = filp->private_data; - struct ring_buffer *buffer = tr->trace_buffer.buffer; char buf[64]; int r; - if (buffer) - r = ring_buffer_record_is_on(buffer); - else - r = 0; - + r = tracer_tracing_is_on(tr); r = sprintf(buf, "%d\n", r); return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); @@ -5661,11 +5700,11 @@ rb_simple_write(struct file *filp, const char __user *ubuf, if (buffer) { mutex_lock(&trace_types_lock); if (val) { - ring_buffer_record_on(buffer); + tracer_tracing_on(tr); if (tr->current_trace->start) tr->current_trace->start(tr); } else { - ring_buffer_record_off(buffer); + tracer_tracing_off(tr); if (tr->current_trace->stop) tr->current_trace->stop(tr); } diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index b19d065a28c..2aefbee93a6 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -373,7 +373,7 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip) struct trace_array_cpu *data; unsigned long flags; - if (likely(!tracer_enabled)) + if (!tracer_enabled || !tracing_is_enabled()) return; cpu = raw_smp_processor_id(); @@ -416,7 +416,7 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip) else return; - if (!tracer_enabled) + if (!tracer_enabled || !tracing_is_enabled()) return; data = per_cpu_ptr(tr->trace_buffer.data, cpu); -- cgit v1.2.3-70-g09d2 From 2d71619c59fac95a5415a326162fa046161b938c Mon Sep 17 00:00:00 2001 From: Alexander Z Lam Date: Mon, 1 Jul 2013 15:31:24 -0700 Subject: tracing: Make trace_marker use the correct per-instance buffer The trace_marker file was present for each new instance created, but it added the trace mark to the global trace buffer instead of to the instance's buffer. Link: http://lkml.kernel.org/r/1372717885-4543-2-git-send-email-azl@google.com Cc: David Sharp Cc: Vaibhav Nagarnaik Cc: Alexander Z Lam Cc: stable@vger.kernel.org # 3.10 Signed-off-by: Alexander Z Lam Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 0dc50711d65..e04e7119633 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4391,6 +4391,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *fpos) { unsigned long addr = (unsigned long)ubuf; + struct trace_array *tr = filp->private_data; struct ring_buffer_event *event; struct ring_buffer *buffer; struct print_entry *entry; @@ -4450,7 +4451,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, local_save_flags(irq_flags); size = sizeof(*entry) + cnt + 2; /* possible \n added */ - buffer = global_trace.trace_buffer.buffer; + buffer = tr->trace_buffer.buffer; event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size, irq_flags, preempt_count()); if (!event) { -- cgit v1.2.3-70-g09d2 From a82274151af2b075163e3c42c828529dee311487 Mon Sep 17 00:00:00 2001 From: Alexander Z Lam Date: Mon, 1 Jul 2013 19:37:54 -0700 Subject: tracing: Protect ftrace_trace_arrays list in trace_events.c There are multiple places where the ftrace_trace_arrays list is accessed in trace_events.c without the trace_types_lock held. Link: http://lkml.kernel.org/r/1372732674-22726-1-git-send-email-azl@google.com Cc: Vaibhav Nagarnaik Cc: David Sharp Cc: Alexander Z Lam Cc: stable@vger.kernel.org # 3.10 Signed-off-by: Alexander Z Lam Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 2 +- kernel/trace/trace.h | 2 ++ kernel/trace/trace_events.c | 11 ++++++++++- 3 files changed, 13 insertions(+), 2 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index e04e7119633..e36da7ff59b 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -266,7 +266,7 @@ static struct tracer *trace_types __read_mostly; /* * trace_types_lock is used to protect the trace_types list. */ -static DEFINE_MUTEX(trace_types_lock); +DEFINE_MUTEX(trace_types_lock); /* * serialize the access of the ring buffer diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index a88939e666b..2c3cba59552 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -224,6 +224,8 @@ enum { extern struct list_head ftrace_trace_arrays; +extern struct mutex trace_types_lock; + /* * The global tracer (top) should be the first trace array added, * but we check the flag anyway. diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 5892470bc2e..35c6f23c71b 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1008,6 +1008,7 @@ static int subsystem_open(struct inode *inode, struct file *filp) int ret; /* Make sure the system still exists */ + mutex_lock(&trace_types_lock); mutex_lock(&event_mutex); list_for_each_entry(tr, &ftrace_trace_arrays, list) { list_for_each_entry(dir, &tr->systems, list) { @@ -1023,6 +1024,7 @@ static int subsystem_open(struct inode *inode, struct file *filp) } exit_loop: mutex_unlock(&event_mutex); + mutex_unlock(&trace_types_lock); if (!system) return -ENODEV; @@ -1617,6 +1619,7 @@ static void __add_event_to_tracers(struct ftrace_event_call *call, int trace_add_event_call(struct ftrace_event_call *call) { int ret; + mutex_lock(&trace_types_lock); mutex_lock(&event_mutex); ret = __register_event(call, NULL); @@ -1624,11 +1627,13 @@ int trace_add_event_call(struct ftrace_event_call *call) __add_event_to_tracers(call, NULL); mutex_unlock(&event_mutex); + mutex_unlock(&trace_types_lock); return ret; } /* - * Must be called under locking both of event_mutex and trace_event_sem. + * Must be called under locking of trace_types_lock, event_mutex and + * trace_event_sem. */ static void __trace_remove_event_call(struct ftrace_event_call *call) { @@ -1640,11 +1645,13 @@ static void __trace_remove_event_call(struct ftrace_event_call *call) /* Remove an event_call */ void trace_remove_event_call(struct ftrace_event_call *call) { + mutex_lock(&trace_types_lock); mutex_lock(&event_mutex); down_write(&trace_event_sem); __trace_remove_event_call(call); up_write(&trace_event_sem); mutex_unlock(&event_mutex); + mutex_unlock(&trace_types_lock); } #define for_each_event(event, start, end) \ @@ -1788,6 +1795,7 @@ static int trace_module_notify(struct notifier_block *self, { struct module *mod = data; + mutex_lock(&trace_types_lock); mutex_lock(&event_mutex); switch (val) { case MODULE_STATE_COMING: @@ -1798,6 +1806,7 @@ static int trace_module_notify(struct notifier_block *self, break; } mutex_unlock(&event_mutex); + mutex_unlock(&trace_types_lock); return 0; } -- cgit v1.2.3-70-g09d2 From ff451961a8b2a17667a7bfa39c86fb9b351445db Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Mon, 1 Jul 2013 22:50:29 -0400 Subject: tracing: Add trace_array_get/put() to handle instance refs better Commit a695cb58162 "tracing: Prevent deleting instances when they are being read" tried to fix a race between deleting a trace instance and reading contents of a trace file. But it wasn't good enough. The following could crash the kernel: # cd /sys/kernel/debug/tracing/instances # ( while :; do mkdir foo; rmdir foo; done ) & # ( while :; do cat foo/trace &> /dev/null; done ) & Luckily this can only be done by root user, but it should be fixed regardless. The problem is that a delete of the file can happen after the reader starts to open the file but before it grabs the trace_types_mutex. The solution is to validate the trace array before using it. If the trace array does not exist in the list of trace arrays, then it returns -ENODEV. There's a possibility that a trace_array could be deleted and a new one created and the open would open its file instead. But that is very minor as it will just return the data of the new trace array, it may confuse the user but it will not crash the system. As this can only be done by root anyway, the race will only occur if root is deleting what its trying to read at the same time. Cc: stable@vger.kernel.org # 3.10 Reported-by: Alexander Lam Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 83 ++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 65 insertions(+), 18 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index e36da7ff59b..6be9df1aa51 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -204,6 +204,37 @@ static struct trace_array global_trace; LIST_HEAD(ftrace_trace_arrays); +int trace_array_get(struct trace_array *this_tr) +{ + struct trace_array *tr; + int ret = -ENODEV; + + mutex_lock(&trace_types_lock); + list_for_each_entry(tr, &ftrace_trace_arrays, list) { + if (tr == this_tr) { + tr->ref++; + ret = 0; + break; + } + } + mutex_unlock(&trace_types_lock); + + return ret; +} + +static void __trace_array_put(struct trace_array *this_tr) +{ + WARN_ON(!this_tr->ref); + this_tr->ref--; +} + +void trace_array_put(struct trace_array *this_tr) +{ + mutex_lock(&trace_types_lock); + __trace_array_put(this_tr); + mutex_unlock(&trace_types_lock); +} + int filter_current_check_discard(struct ring_buffer *buffer, struct ftrace_event_call *call, void *rec, struct ring_buffer_event *event) @@ -2831,10 +2862,9 @@ static const struct seq_operations tracer_seq_ops = { }; static struct trace_iterator * -__tracing_open(struct inode *inode, struct file *file, bool snapshot) +__tracing_open(struct trace_array *tr, struct trace_cpu *tc, + struct inode *inode, struct file *file, bool snapshot) { - struct trace_cpu *tc = inode->i_private; - struct trace_array *tr = tc->tr; struct trace_iterator *iter; int cpu; @@ -2913,8 +2943,6 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot) tracing_iter_reset(iter, cpu); } - tr->ref++; - mutex_unlock(&trace_types_lock); return iter; @@ -2944,17 +2972,20 @@ static int tracing_release(struct inode *inode, struct file *file) struct trace_array *tr; int cpu; - if (!(file->f_mode & FMODE_READ)) + /* Writes do not use seq_file, need to grab tr from inode */ + if (!(file->f_mode & FMODE_READ)) { + struct trace_cpu *tc = inode->i_private; + + trace_array_put(tc->tr); return 0; + } iter = m->private; tr = iter->tr; + trace_array_put(tr); mutex_lock(&trace_types_lock); - WARN_ON(!tr->ref); - tr->ref--; - for_each_tracing_cpu(cpu) { if (iter->buffer_iter[cpu]) ring_buffer_read_finish(iter->buffer_iter[cpu]); @@ -2973,20 +3004,23 @@ static int tracing_release(struct inode *inode, struct file *file) kfree(iter->trace); kfree(iter->buffer_iter); seq_release_private(inode, file); + return 0; } static int tracing_open(struct inode *inode, struct file *file) { + struct trace_cpu *tc = inode->i_private; + struct trace_array *tr = tc->tr; struct trace_iterator *iter; int ret = 0; + if (trace_array_get(tr) < 0) + return -ENODEV; + /* If this file was open for write, then erase contents */ if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { - struct trace_cpu *tc = inode->i_private; - struct trace_array *tr = tc->tr; - if (tc->cpu == RING_BUFFER_ALL_CPUS) tracing_reset_online_cpus(&tr->trace_buffer); else @@ -2994,12 +3028,16 @@ static int tracing_open(struct inode *inode, struct file *file) } if (file->f_mode & FMODE_READ) { - iter = __tracing_open(inode, file, false); + iter = __tracing_open(tr, tc, inode, file, false); if (IS_ERR(iter)) ret = PTR_ERR(iter); else if (trace_flags & TRACE_ITER_LATENCY_FMT) iter->iter_flags |= TRACE_FILE_LAT_FMT; } + + if (ret < 0) + trace_array_put(tr); + return ret; } @@ -4575,12 +4613,16 @@ struct ftrace_buffer_info { static int tracing_snapshot_open(struct inode *inode, struct file *file) { struct trace_cpu *tc = inode->i_private; + struct trace_array *tr = tc->tr; struct trace_iterator *iter; struct seq_file *m; int ret = 0; + if (trace_array_get(tr) < 0) + return -ENODEV; + if (file->f_mode & FMODE_READ) { - iter = __tracing_open(inode, file, true); + iter = __tracing_open(tr, tc, inode, file, true); if (IS_ERR(iter)) ret = PTR_ERR(iter); } else { @@ -4593,13 +4635,16 @@ static int tracing_snapshot_open(struct inode *inode, struct file *file) kfree(m); return -ENOMEM; } - iter->tr = tc->tr; + iter->tr = tr; iter->trace_buffer = &tc->tr->max_buffer; iter->cpu_file = tc->cpu; m->private = iter; file->private_data = m; } + if (ret < 0) + trace_array_put(tr); + return ret; } @@ -4680,9 +4725,12 @@ out: static int tracing_snapshot_release(struct inode *inode, struct file *file) { struct seq_file *m = file->private_data; + int ret; + + ret = tracing_release(inode, file); if (file->f_mode & FMODE_READ) - return tracing_release(inode, file); + return ret; /* If write only, the seq_file is just a stub */ if (m) @@ -4927,8 +4975,7 @@ static int tracing_buffers_release(struct inode *inode, struct file *file) mutex_lock(&trace_types_lock); - WARN_ON(!iter->tr->ref); - iter->tr->ref--; + __trace_array_put(iter->tr); if (info->spare) ring_buffer_free_read_page(iter->trace_buffer->buffer, info->spare); -- cgit v1.2.3-70-g09d2 From 7b85af63034818e43aee6c1d7bf1c7c6796a9073 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Mon, 1 Jul 2013 23:34:22 -0400 Subject: tracing: Get trace_array ref counts when accessing trace files When a trace file is opened that may access a trace array, it must increment its ref count to prevent it from being deleted. Cc: stable@vger.kernel.org # 3.10 Reported-by: Alexander Lam Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 121 +++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 112 insertions(+), 9 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 6be9df1aa51..6d9bd9b43e4 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2965,6 +2965,43 @@ int tracing_open_generic(struct inode *inode, struct file *filp) return 0; } +/* + * Open and update trace_array ref count. + * Must have the current trace_array passed to it. + */ +int tracing_open_generic_tr(struct inode *inode, struct file *filp) +{ + struct trace_array *tr = inode->i_private; + + if (tracing_disabled) + return -ENODEV; + + if (trace_array_get(tr) < 0) + return -ENODEV; + + filp->private_data = inode->i_private; + + return 0; + +} + +int tracing_open_generic_tc(struct inode *inode, struct file *filp) +{ + struct trace_cpu *tc = inode->i_private; + struct trace_array *tr = tc->tr; + + if (tracing_disabled) + return -ENODEV; + + if (trace_array_get(tr) < 0) + return -ENODEV; + + filp->private_data = inode->i_private; + + return 0; + +} + static int tracing_release(struct inode *inode, struct file *file) { struct seq_file *m = file->private_data; @@ -3008,6 +3045,32 @@ static int tracing_release(struct inode *inode, struct file *file) return 0; } +static int tracing_release_generic_tr(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + + trace_array_put(tr); + return 0; +} + +static int tracing_release_generic_tc(struct inode *inode, struct file *file) +{ + struct trace_cpu *tc = inode->i_private; + struct trace_array *tr = tc->tr; + + trace_array_put(tr); + return 0; +} + +static int tracing_single_release_tr(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + + trace_array_put(tr); + + return single_release(inode, file); +} + static int tracing_open(struct inode *inode, struct file *file) { struct trace_cpu *tc = inode->i_private; @@ -3394,9 +3457,14 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf, static int tracing_trace_options_open(struct inode *inode, struct file *file) { + struct trace_array *tr = inode->i_private; + if (tracing_disabled) return -ENODEV; + if (trace_array_get(tr) < 0) + return -ENODEV; + return single_open(file, tracing_trace_options_show, inode->i_private); } @@ -3404,7 +3472,7 @@ static const struct file_operations tracing_iter_fops = { .open = tracing_trace_options_open, .read = seq_read, .llseek = seq_lseek, - .release = single_release, + .release = tracing_single_release_tr, .write = tracing_trace_options_write, }; @@ -3892,6 +3960,9 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp) if (tracing_disabled) return -ENODEV; + if (trace_array_get(tr) < 0) + return -ENODEV; + mutex_lock(&trace_types_lock); /* create a buffer to store the information to pass to userspace */ @@ -3944,6 +4015,7 @@ out: fail: kfree(iter->trace); kfree(iter); + __trace_array_put(tr); mutex_unlock(&trace_types_lock); return ret; } @@ -3951,6 +4023,8 @@ fail: static int tracing_release_pipe(struct inode *inode, struct file *file) { struct trace_iterator *iter = file->private_data; + struct trace_cpu *tc = inode->i_private; + struct trace_array *tr = tc->tr; mutex_lock(&trace_types_lock); @@ -3964,6 +4038,8 @@ static int tracing_release_pipe(struct inode *inode, struct file *file) kfree(iter->trace); kfree(iter); + trace_array_put(tr); + return 0; } @@ -4421,6 +4497,8 @@ tracing_free_buffer_release(struct inode *inode, struct file *filp) /* resize the ring buffer to 0 */ tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS); + trace_array_put(tr); + return 0; } @@ -4597,10 +4675,20 @@ static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf, static int tracing_clock_open(struct inode *inode, struct file *file) { + struct trace_array *tr = inode->i_private; + int ret; + if (tracing_disabled) return -ENODEV; - return single_open(file, tracing_clock_show, inode->i_private); + if (trace_array_get(tr)) + return -ENODEV; + + ret = single_open(file, tracing_clock_show, inode->i_private); + if (ret < 0) + trace_array_put(tr); + + return ret; } struct ftrace_buffer_info { @@ -4796,34 +4884,38 @@ static const struct file_operations tracing_pipe_fops = { }; static const struct file_operations tracing_entries_fops = { - .open = tracing_open_generic, + .open = tracing_open_generic_tc, .read = tracing_entries_read, .write = tracing_entries_write, .llseek = generic_file_llseek, + .release = tracing_release_generic_tc, }; static const struct file_operations tracing_total_entries_fops = { - .open = tracing_open_generic, + .open = tracing_open_generic_tr, .read = tracing_total_entries_read, .llseek = generic_file_llseek, + .release = tracing_release_generic_tr, }; static const struct file_operations tracing_free_buffer_fops = { + .open = tracing_open_generic_tr, .write = tracing_free_buffer_write, .release = tracing_free_buffer_release, }; static const struct file_operations tracing_mark_fops = { - .open = tracing_open_generic, + .open = tracing_open_generic_tr, .write = tracing_mark_write, .llseek = generic_file_llseek, + .release = tracing_release_generic_tr, }; static const struct file_operations trace_clock_fops = { .open = tracing_clock_open, .read = seq_read, .llseek = seq_lseek, - .release = single_release, + .release = tracing_single_release_tr, .write = tracing_clock_write, }; @@ -4851,13 +4943,19 @@ static int tracing_buffers_open(struct inode *inode, struct file *filp) struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; struct ftrace_buffer_info *info; + int ret; if (tracing_disabled) return -ENODEV; + if (trace_array_get(tr) < 0) + return -ENODEV; + info = kzalloc(sizeof(*info), GFP_KERNEL); - if (!info) + if (!info) { + trace_array_put(tr); return -ENOMEM; + } mutex_lock(&trace_types_lock); @@ -4875,7 +4973,11 @@ static int tracing_buffers_open(struct inode *inode, struct file *filp) mutex_unlock(&trace_types_lock); - return nonseekable_open(inode, filp); + ret = nonseekable_open(inode, filp); + if (ret < 0) + trace_array_put(tr); + + return ret; } static unsigned int @@ -5765,9 +5867,10 @@ rb_simple_write(struct file *filp, const char __user *ubuf, } static const struct file_operations rb_simple_fops = { - .open = tracing_open_generic, + .open = tracing_open_generic_tr, .read = rb_simple_read, .write = rb_simple_write, + .release = tracing_release_generic_tr, .llseek = default_llseek, }; -- cgit v1.2.3-70-g09d2 From 5280bcef91e706770cc1706eb97353e3513322b9 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Tue, 2 Jul 2013 19:59:57 -0400 Subject: tracing: Make tracer_tracing_{off,on,is_on}() static I have patches that will use tracer_tracing_on/off/is_on() in other files, but as they are not ready to be merged yet, and Fengguang Wu's sparse scripts pointed out that these functions were not declared anywhere, I'll make them static for now. When these functions are required to be used elsewhere, I'll remove the static then. Reported-by: kbuild test robot Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 6d9bd9b43e4..48aceb8a032 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -387,7 +387,7 @@ unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | TRACE_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS | TRACE_ITER_FUNCTION; -void tracer_tracing_on(struct trace_array *tr) +static void tracer_tracing_on(struct trace_array *tr) { if (tr->trace_buffer.buffer) ring_buffer_record_on(tr->trace_buffer.buffer); @@ -606,7 +606,7 @@ void tracing_snapshot_alloc(void) EXPORT_SYMBOL_GPL(tracing_snapshot_alloc); #endif /* CONFIG_TRACER_SNAPSHOT */ -void tracer_tracing_off(struct trace_array *tr) +static void tracer_tracing_off(struct trace_array *tr) { if (tr->trace_buffer.buffer) ring_buffer_record_off(tr->trace_buffer.buffer); @@ -649,7 +649,7 @@ void disable_trace_on_warning(void) * * Shows real state of the ring buffer if it is enabled or not. */ -int tracer_tracing_is_on(struct trace_array *tr) +static int tracer_tracing_is_on(struct trace_array *tr) { if (tr->trace_buffer.buffer) return ring_buffer_record_is_on(tr->trace_buffer.buffer); -- cgit v1.2.3-70-g09d2 From 8de1eb02778b64f8b292db531cf39a429f84315f Mon Sep 17 00:00:00 2001 From: "zhangwei(Jovi)" Date: Wed, 10 Apr 2013 11:26:30 +0800 Subject: tracing: Remove ftrace() function The only caller of function ftrace(...) was removed a long time ago, so remove the function body as well. Link: http://lkml.kernel.org/r/1365564393-10972-10-git-send-email-jovi.zhangwei@huawei.com Signed-off-by: zhangwei(Jovi) Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 9 --------- kernel/trace/trace.h | 5 ----- 2 files changed, 14 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 48aceb8a032..f6fed9e51c6 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1637,15 +1637,6 @@ trace_function(struct trace_array *tr, __buffer_unlock_commit(buffer, event); } -void -ftrace(struct trace_array *tr, struct trace_array_cpu *data, - unsigned long ip, unsigned long parent_ip, unsigned long flags, - int pc) -{ - if (likely(!atomic_read(&data->disabled))) - trace_function(tr, ip, parent_ip, flags, pc); -} - #ifdef CONFIG_STACKTRACE #define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long)) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 1cbba04976b..a4ed382dea2 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -559,11 +559,6 @@ void tracing_iter_reset(struct trace_iterator *iter, int cpu); void poll_wait_pipe(struct trace_iterator *iter); -void ftrace(struct trace_array *tr, - struct trace_array_cpu *data, - unsigned long ip, - unsigned long parent_ip, - unsigned long flags, int pc); void tracing_sched_switch_trace(struct trace_array *tr, struct task_struct *prev, struct task_struct *next, -- cgit v1.2.3-70-g09d2 From dcc302232c1f9b3ca16f6b8ee190eb0b1a8a0da3 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Tue, 2 Jul 2013 20:30:52 -0400 Subject: tracing: Make tracing_open_generic_{tr,tc}() static I have patches that will use tracing_open_generic_tr/tc() in other files, but as they are not ready to be merged yet, and Fengguang Wu's sparse scripts pointed out that these functions were not declared anywhere, I'll make them static for now. When these functions are required to be used elsewhere, I'll remove the static then. Reported-by: kbuild test robot Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index f6fed9e51c6..dc473b51415 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2960,7 +2960,7 @@ int tracing_open_generic(struct inode *inode, struct file *filp) * Open and update trace_array ref count. * Must have the current trace_array passed to it. */ -int tracing_open_generic_tr(struct inode *inode, struct file *filp) +static int tracing_open_generic_tr(struct inode *inode, struct file *filp) { struct trace_array *tr = inode->i_private; @@ -2976,7 +2976,7 @@ int tracing_open_generic_tr(struct inode *inode, struct file *filp) } -int tracing_open_generic_tc(struct inode *inode, struct file *filp) +static int tracing_open_generic_tc(struct inode *inode, struct file *filp) { struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; -- cgit v1.2.3-70-g09d2 From 991821c86c2fb6cc4104ce679247864dbc070a83 Mon Sep 17 00:00:00 2001 From: "zhangwei(Jovi)" Date: Mon, 15 Jul 2013 16:32:34 +0800 Subject: tracing: Use correct config guard CONFIG_STACK_TRACER We should use CONFIG_STACK_TRACER to guard readme text of stack tracer related file, not CONFIG_STACKTRACE. Link: http://lkml.kernel.org/r/51E3B3A2.8080609@huawei.com Signed-off-by: zhangwei(Jovi) Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 0cd500bffd9..25b91afc29e 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3537,14 +3537,14 @@ static const char readme_msg[] = "\n snapshot\t\t- Like 'trace' but shows the content of the static snapshot buffer\n" "\t\t\t Read the contents for more information\n" #endif -#ifdef CONFIG_STACKTRACE +#ifdef CONFIG_STACK_TRACER " stack_trace\t\t- Shows the max stack trace when active\n" " stack_max_size\t- Shows current max stack size that was traced\n" "\t\t\t Write into this file to reset the max size (trigger a new trace)\n" #ifdef CONFIG_DYNAMIC_FTRACE " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace traces\n" #endif -#endif /* CONFIG_STACKTRACE */ +#endif /* CONFIG_STACK_TRACER */ ; static ssize_t -- cgit v1.2.3-70-g09d2 From 609e85a70bcd0eedf4ec60639dbcfb1ab011e054 Mon Sep 17 00:00:00 2001 From: Alexander Z Lam Date: Wed, 10 Jul 2013 17:34:34 -0700 Subject: tracing: Fix error handling to ensure instances can always be removed Remove debugfs directories for tracing instances during creation if an error occurs causing the trace_array for that instance to not be added to ftrace_trace_arrays. If the directory continues to exist after the error, it cannot be removed because the respective trace_array is not in ftrace_trace_arrays. Link: http://lkml.kernel.org/r/1373502874-1706-2-git-send-email-azl@google.com Cc: stable@vger.kernel.org # 3.10 Cc: Vaibhav Nagarnaik Cc: David Sharp Cc: Alexander Z Lam Signed-off-by: Alexander Z Lam Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 25b91afc29e..7c3da7bca05 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5973,8 +5973,10 @@ static int new_instance_create(const char *name) goto out_free_tr; ret = event_trace_add_tracer(tr->dir, tr); - if (ret) + if (ret) { + debugfs_remove_recursive(tr->dir); goto out_free_tr; + } init_tracer_debugfs(tr, tr->dir); -- cgit v1.2.3-70-g09d2 From f77d09a384676bde6445413949d9d2c508ff3e62 Mon Sep 17 00:00:00 2001 From: Alexander Z Lam Date: Thu, 18 Jul 2013 11:18:44 -0700 Subject: tracing: Miscellaneous fixes for trace_array ref counting Some error paths did not handle ref counting properly, and some trace files need ref counting. Link: http://lkml.kernel.org/r/1374171524-11948-1-git-send-email-azl@google.com Cc: stable@vger.kernel.org # 3.10 Cc: Vaibhav Nagarnaik Cc: David Sharp Cc: Alexander Z Lam Signed-off-by: Alexander Z Lam Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 24 ++++++++++++++++++------ kernel/trace/trace_events.c | 21 +++++++++++++++++++-- 2 files changed, 37 insertions(+), 8 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 7c3da7bca05..7d9ceab4256 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3008,7 +3008,6 @@ static int tracing_release(struct inode *inode, struct file *file) iter = m->private; tr = iter->tr; - trace_array_put(tr); mutex_lock(&trace_types_lock); @@ -3023,6 +3022,9 @@ static int tracing_release(struct inode *inode, struct file *file) if (!iter->snapshot) /* reenable tracing if it was previously enabled */ tracing_start_tr(tr); + + __trace_array_put(tr); + mutex_unlock(&trace_types_lock); mutex_destroy(&iter->mutex); @@ -3447,6 +3449,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf, static int tracing_trace_options_open(struct inode *inode, struct file *file) { struct trace_array *tr = inode->i_private; + int ret; if (tracing_disabled) return -ENODEV; @@ -3454,7 +3457,11 @@ static int tracing_trace_options_open(struct inode *inode, struct file *file) if (trace_array_get(tr) < 0) return -ENODEV; - return single_open(file, tracing_trace_options_show, inode->i_private); + ret = single_open(file, tracing_trace_options_show, inode->i_private); + if (ret < 0) + trace_array_put(tr); + + return ret; } static const struct file_operations tracing_iter_fops = { @@ -3958,6 +3965,7 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp) iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) { ret = -ENOMEM; + __trace_array_put(tr); goto out; } @@ -4704,21 +4712,24 @@ static int tracing_snapshot_open(struct inode *inode, struct file *file) ret = PTR_ERR(iter); } else { /* Writes still need the seq_file to hold the private data */ + ret = -ENOMEM; m = kzalloc(sizeof(*m), GFP_KERNEL); if (!m) - return -ENOMEM; + goto out; iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) { kfree(m); - return -ENOMEM; + goto out; } + ret = 0; + iter->tr = tr; iter->trace_buffer = &tc->tr->max_buffer; iter->cpu_file = tc->cpu; m->private = iter; file->private_data = m; } - +out: if (ret < 0) trace_array_put(tr); @@ -5328,9 +5339,10 @@ tracing_stats_read(struct file *filp, char __user *ubuf, } static const struct file_operations tracing_stats_fops = { - .open = tracing_open_generic, + .open = tracing_open_generic_tc, .read = tracing_stats_read, .llseek = generic_file_llseek, + .release = tracing_release_generic_tc, }; #ifdef CONFIG_DYNAMIC_FTRACE diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 7d854290bf8..7a75cb22eab 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1218,6 +1218,7 @@ show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) static int ftrace_event_avail_open(struct inode *inode, struct file *file); static int ftrace_event_set_open(struct inode *inode, struct file *file); +static int ftrace_event_release(struct inode *inode, struct file *file); static const struct seq_operations show_event_seq_ops = { .start = t_start, @@ -1245,7 +1246,7 @@ static const struct file_operations ftrace_set_event_fops = { .read = seq_read, .write = ftrace_event_write, .llseek = seq_lseek, - .release = seq_release, + .release = ftrace_event_release, }; static const struct file_operations ftrace_enable_fops = { @@ -1323,6 +1324,15 @@ ftrace_event_open(struct inode *inode, struct file *file, return ret; } +static int ftrace_event_release(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + + trace_array_put(tr); + + return seq_release(inode, file); +} + static int ftrace_event_avail_open(struct inode *inode, struct file *file) { @@ -1336,12 +1346,19 @@ ftrace_event_set_open(struct inode *inode, struct file *file) { const struct seq_operations *seq_ops = &show_set_event_seq_ops; struct trace_array *tr = inode->i_private; + int ret; + + if (trace_array_get(tr) < 0) + return -ENODEV; if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) ftrace_clear_events(tr); - return ftrace_event_open(inode, file, seq_ops); + ret = ftrace_event_open(inode, file, seq_ops); + if (ret < 0) + trace_array_put(tr); + return ret; } static struct event_subsystem * -- cgit v1.2.3-70-g09d2 From e70e78e3c83b536730e31231dd9b979768d8df3c Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 19 Jul 2013 17:36:44 +0200 Subject: tracing: Kill the unbalanced tr->ref++ in tracing_buffers_open() tracing_buffers_open() does trace_array_get() and then it wrongly inrcements tr->ref again under trace_types_lock. This means that every caller leaks trace_array: # cd /sys/kernel/debug/tracing/ # mkdir instances/X # true < instances/X/per_cpu/cpu0/trace_pipe_raw # rmdir instances/X rmdir: failed to remove `instances/X': Device or resource busy Link: http://lkml.kernel.org/r/20130719153644.GA18899@redhat.com Cc: Ingo Molnar Cc: Frederic Weisbecker Cc: Masami Hiramatsu Cc: stable@vger.kernel.org # 3.10 Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 7d9ceab4256..3f2477713ac 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4959,8 +4959,6 @@ static int tracing_buffers_open(struct inode *inode, struct file *filp) mutex_lock(&trace_types_lock); - tr->ref++; - info->iter.tr = tr; info->iter.cpu_file = tc->cpu; info->iter.trace = tr->current_trace; -- cgit v1.2.3-70-g09d2 From 649e9c70da6bfbeb563193a35d3424a5aa7c0d38 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 23 Jul 2013 17:25:54 +0200 Subject: tracing: Introduce trace_create_cpu_file() and tracing_get_cpu() Every "file_operations" used by tracing_init_debugfs_percpu is buggy. f_op->open/etc does: 1. struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; 2. trace_array_get(tr) or fail; 3. do_something(tc); But tc (and tr) can be already freed before trace_array_get() is called. And it doesn't matter whether this file is per-cpu or it was created by init_tracer_debugfs(), free_percpu() or kfree() are equally bad. Note that even 1. is not safe, the freed memory can be unmapped. But even if it was safe trace_array_get() can wrongly succeed if we also race with the next new_instance_create() which can re-allocate the same tr, or tc was overwritten and ->tr points to the valid tr. In this case 3. uses the freed/reused memory. Add the new trivial helper, trace_create_cpu_file() which simply calls trace_create_file() and encodes "cpu" in "struct inode". Another helper, tracing_get_cpu() will be used to read cpu_nr-or-RING_BUFFER_ALL_CPUS. The patch abuses ->i_cdev to encode the number, it is never used unless the file is S_ISCHR(). But we could use something else, say, i_bytes or even ->d_fsdata. In any case this hack is hidden inside these 2 helpers, it would be trivial to change them if needed. This patch only changes tracing_init_debugfs_percpu() to use the new trace_create_cpu_file(), the next patches will change file_operations. Note: tracing_get_cpu(inode) is always safe but you can't trust the result unless trace_array_get() was called, without trace_types_lock which acts as a barrier it can wrongly return RING_BUFFER_ALL_CPUS. Link: http://lkml.kernel.org/r/20130723152554.GA23710@redhat.com Cc: Al Viro Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 50 ++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 36 insertions(+), 14 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 3f2477713ac..cfff63c2148 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2843,6 +2843,17 @@ static int s_show(struct seq_file *m, void *v) return 0; } +/* + * Should be used after trace_array_get(), trace_types_lock + * ensures that i_cdev was already initialized. + */ +static inline int tracing_get_cpu(struct inode *inode) +{ + if (inode->i_cdev) /* See trace_create_cpu_file() */ + return (long)inode->i_cdev - 1; + return RING_BUFFER_ALL_CPUS; +} + static const struct seq_operations tracer_seq_ops = { .start = s_start, .next = s_next, @@ -5529,6 +5540,17 @@ static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu) return tr->percpu_dir; } +static struct dentry * +trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent, + void *data, long cpu, const struct file_operations *fops) +{ + struct dentry *ret = trace_create_file(name, mode, parent, data, fops); + + if (ret) /* See tracing_get_cpu() */ + ret->d_inode->i_cdev = (void *)(cpu + 1); + return ret; +} + static void tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) { @@ -5548,28 +5570,28 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) } /* per cpu trace_pipe */ - trace_create_file("trace_pipe", 0444, d_cpu, - (void *)&data->trace_cpu, &tracing_pipe_fops); + trace_create_cpu_file("trace_pipe", 0444, d_cpu, + &data->trace_cpu, cpu, &tracing_pipe_fops); /* per cpu trace */ - trace_create_file("trace", 0644, d_cpu, - (void *)&data->trace_cpu, &tracing_fops); + trace_create_cpu_file("trace", 0644, d_cpu, + &data->trace_cpu, cpu, &tracing_fops); - trace_create_file("trace_pipe_raw", 0444, d_cpu, - (void *)&data->trace_cpu, &tracing_buffers_fops); + trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu, + &data->trace_cpu, cpu, &tracing_buffers_fops); - trace_create_file("stats", 0444, d_cpu, - (void *)&data->trace_cpu, &tracing_stats_fops); + trace_create_cpu_file("stats", 0444, d_cpu, + &data->trace_cpu, cpu, &tracing_stats_fops); - trace_create_file("buffer_size_kb", 0444, d_cpu, - (void *)&data->trace_cpu, &tracing_entries_fops); + trace_create_cpu_file("buffer_size_kb", 0444, d_cpu, + &data->trace_cpu, cpu, &tracing_entries_fops); #ifdef CONFIG_TRACER_SNAPSHOT - trace_create_file("snapshot", 0644, d_cpu, - (void *)&data->trace_cpu, &snapshot_fops); + trace_create_cpu_file("snapshot", 0644, d_cpu, + &data->trace_cpu, cpu, &snapshot_fops); - trace_create_file("snapshot_raw", 0444, d_cpu, - (void *)&data->trace_cpu, &snapshot_raw_fops); + trace_create_cpu_file("snapshot_raw", 0444, d_cpu, + &data->trace_cpu, cpu, &snapshot_raw_fops); #endif } -- cgit v1.2.3-70-g09d2 From 15544209cb0b5312e5220a9337a1fe61d1a1f2d9 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 23 Jul 2013 17:25:57 +0200 Subject: tracing: Change tracing_pipe_fops() to rely on tracing_get_cpu() tracing_open_pipe() is racy, the memory inode->i_private points to can be already freed. Change debugfs_create_file("trace_pipe", data) callers to to pass "data = tr", tracing_open_pipe() can use tracing_get_cpu(). Link: http://lkml.kernel.org/r/20130723152557.GA23717@redhat.com Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index cfff63c2148..51a99ef2a6e 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3959,8 +3959,7 @@ tracing_max_lat_write(struct file *filp, const char __user *ubuf, static int tracing_open_pipe(struct inode *inode, struct file *filp) { - struct trace_cpu *tc = inode->i_private; - struct trace_array *tr = tc->tr; + struct trace_array *tr = inode->i_private; struct trace_iterator *iter; int ret = 0; @@ -4006,9 +4005,9 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp) if (trace_clocks[tr->clock_id].in_ns) iter->iter_flags |= TRACE_FILE_TIME_IN_NS; - iter->cpu_file = tc->cpu; - iter->tr = tc->tr; - iter->trace_buffer = &tc->tr->trace_buffer; + iter->tr = tr; + iter->trace_buffer = &tr->trace_buffer; + iter->cpu_file = tracing_get_cpu(inode); mutex_init(&iter->mutex); filp->private_data = iter; @@ -4031,8 +4030,7 @@ fail: static int tracing_release_pipe(struct inode *inode, struct file *file) { struct trace_iterator *iter = file->private_data; - struct trace_cpu *tc = inode->i_private; - struct trace_array *tr = tc->tr; + struct trace_array *tr = inode->i_private; mutex_lock(&trace_types_lock); @@ -5571,7 +5569,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) /* per cpu trace_pipe */ trace_create_cpu_file("trace_pipe", 0444, d_cpu, - &data->trace_cpu, cpu, &tracing_pipe_fops); + tr, cpu, &tracing_pipe_fops); /* per cpu trace */ trace_create_cpu_file("trace", 0644, d_cpu, @@ -6157,7 +6155,7 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer) (void *)&tr->trace_cpu, &tracing_fops); trace_create_file("trace_pipe", 0444, d_tracer, - (void *)&tr->trace_cpu, &tracing_pipe_fops); + tr, &tracing_pipe_fops); trace_create_file("buffer_size_kb", 0644, d_tracer, (void *)&tr->trace_cpu, &tracing_entries_fops); -- cgit v1.2.3-70-g09d2 From 46ef2be0d1d5ccea0c41bb606143586daadd537c Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 23 Jul 2013 17:26:00 +0200 Subject: tracing: Change tracing_buffers_fops to rely on tracing_get_cpu() tracing_buffers_open() is racy, the memory inode->i_private points to can be already freed. Change debugfs_create_file("trace_pipe_raw", data) caller to pass "data = tr", tracing_buffers_open() can use tracing_get_cpu(). Change debugfs_create_file("snapshot_raw_fops", data) caller too, this file uses tracing_buffers_open/release. Link: http://lkml.kernel.org/r/20130723152600.GA23720@redhat.com Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 51a99ef2a6e..30c058a56ff 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4949,8 +4949,7 @@ static const struct file_operations snapshot_raw_fops = { static int tracing_buffers_open(struct inode *inode, struct file *filp) { - struct trace_cpu *tc = inode->i_private; - struct trace_array *tr = tc->tr; + struct trace_array *tr = inode->i_private; struct ftrace_buffer_info *info; int ret; @@ -4969,7 +4968,7 @@ static int tracing_buffers_open(struct inode *inode, struct file *filp) mutex_lock(&trace_types_lock); info->iter.tr = tr; - info->iter.cpu_file = tc->cpu; + info->iter.cpu_file = tracing_get_cpu(inode); info->iter.trace = tr->current_trace; info->iter.trace_buffer = &tr->trace_buffer; info->spare = NULL; @@ -5576,7 +5575,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) &data->trace_cpu, cpu, &tracing_fops); trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu, - &data->trace_cpu, cpu, &tracing_buffers_fops); + tr, cpu, &tracing_buffers_fops); trace_create_cpu_file("stats", 0444, d_cpu, &data->trace_cpu, cpu, &tracing_stats_fops); @@ -5589,7 +5588,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) &data->trace_cpu, cpu, &snapshot_fops); trace_create_cpu_file("snapshot_raw", 0444, d_cpu, - &data->trace_cpu, cpu, &snapshot_raw_fops); + tr, cpu, &snapshot_raw_fops); #endif } -- cgit v1.2.3-70-g09d2 From 4d3435b8a4c3357695e09c5e7a3bf73a19fca5b0 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 23 Jul 2013 17:26:03 +0200 Subject: tracing: Change tracing_stats_fops to rely on tracing_get_cpu() tracing_open_generic_tc() is racy, the memory inode->i_private points to can be already freed. 1. Change one of its users, tracing_stats_fops, to use tracing_*_generic_tr() instead. 2. Change trace_create_cpu_file("stats", data) to pass "data = tr". 3. Change tracing_stats_read() to use tracing_get_cpu(). Link: http://lkml.kernel.org/r/20130723152603.GA23727@redhat.com Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 30c058a56ff..e29dc8f69aa 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2982,7 +2982,6 @@ static int tracing_open_generic_tr(struct inode *inode, struct file *filp) filp->private_data = inode->i_private; return 0; - } static int tracing_open_generic_tc(struct inode *inode, struct file *filp) @@ -5285,14 +5284,14 @@ static ssize_t tracing_stats_read(struct file *filp, char __user *ubuf, size_t count, loff_t *ppos) { - struct trace_cpu *tc = filp->private_data; - struct trace_array *tr = tc->tr; + struct inode *inode = file_inode(filp); + struct trace_array *tr = inode->i_private; struct trace_buffer *trace_buf = &tr->trace_buffer; + int cpu = tracing_get_cpu(inode); struct trace_seq *s; unsigned long cnt; unsigned long long t; unsigned long usec_rem; - int cpu = tc->cpu; s = kmalloc(sizeof(*s), GFP_KERNEL); if (!s) @@ -5345,10 +5344,10 @@ tracing_stats_read(struct file *filp, char __user *ubuf, } static const struct file_operations tracing_stats_fops = { - .open = tracing_open_generic_tc, + .open = tracing_open_generic_tr, .read = tracing_stats_read, .llseek = generic_file_llseek, - .release = tracing_release_generic_tc, + .release = tracing_release_generic_tr, }; #ifdef CONFIG_DYNAMIC_FTRACE @@ -5578,7 +5577,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) tr, cpu, &tracing_buffers_fops); trace_create_cpu_file("stats", 0444, d_cpu, - &data->trace_cpu, cpu, &tracing_stats_fops); + tr, cpu, &tracing_stats_fops); trace_create_cpu_file("buffer_size_kb", 0444, d_cpu, &data->trace_cpu, cpu, &tracing_entries_fops); -- cgit v1.2.3-70-g09d2 From 0bc392ee46d0fd8e6b678457ef71f074f19a03c5 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 23 Jul 2013 17:26:06 +0200 Subject: tracing: Change tracing_entries_fops to rely on tracing_get_cpu() tracing_open_generic_tc() is racy, the memory inode->i_private points to can be already freed. 1. Change its last user, tracing_entries_fops, to use tracing_*_generic_tr() instead. 2. Change debugfs_create_file("buffer_size_kb", data) callers to pass "data = tr". 3. Change tracing_entries_read() and tracing_entries_write() to use tracing_get_cpu(). 4. Kill the no longer used tracing_open_generic_tc() and tracing_release_generic_tc(). Link: http://lkml.kernel.org/r/20130723152606.GA23730@redhat.com Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 49 ++++++++++++------------------------------------- 1 file changed, 12 insertions(+), 37 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index e29dc8f69aa..68b46851666 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2984,23 +2984,6 @@ static int tracing_open_generic_tr(struct inode *inode, struct file *filp) return 0; } -static int tracing_open_generic_tc(struct inode *inode, struct file *filp) -{ - struct trace_cpu *tc = inode->i_private; - struct trace_array *tr = tc->tr; - - if (tracing_disabled) - return -ENODEV; - - if (trace_array_get(tr) < 0) - return -ENODEV; - - filp->private_data = inode->i_private; - - return 0; - -} - static int tracing_release(struct inode *inode, struct file *file) { struct seq_file *m = file->private_data; @@ -3054,15 +3037,6 @@ static int tracing_release_generic_tr(struct inode *inode, struct file *file) return 0; } -static int tracing_release_generic_tc(struct inode *inode, struct file *file) -{ - struct trace_cpu *tc = inode->i_private; - struct trace_array *tr = tc->tr; - - trace_array_put(tr); - return 0; -} - static int tracing_single_release_tr(struct inode *inode, struct file *file) { struct trace_array *tr = inode->i_private; @@ -4382,15 +4356,16 @@ static ssize_t tracing_entries_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { - struct trace_cpu *tc = filp->private_data; - struct trace_array *tr = tc->tr; + struct inode *inode = file_inode(filp); + struct trace_array *tr = inode->i_private; + int cpu = tracing_get_cpu(inode); char buf[64]; int r = 0; ssize_t ret; mutex_lock(&trace_types_lock); - if (tc->cpu == RING_BUFFER_ALL_CPUS) { + if (cpu == RING_BUFFER_ALL_CPUS) { int cpu, buf_size_same; unsigned long size; @@ -4417,7 +4392,7 @@ tracing_entries_read(struct file *filp, char __user *ubuf, } else r = sprintf(buf, "X\n"); } else - r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, tc->cpu)->entries >> 10); + r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10); mutex_unlock(&trace_types_lock); @@ -4429,7 +4404,8 @@ static ssize_t tracing_entries_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { - struct trace_cpu *tc = filp->private_data; + struct inode *inode = file_inode(filp); + struct trace_array *tr = inode->i_private; unsigned long val; int ret; @@ -4443,8 +4419,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, /* value is in KB */ val <<= 10; - - ret = tracing_resize_ring_buffer(tc->tr, val, tc->cpu); + ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode)); if (ret < 0) return ret; @@ -4892,11 +4867,11 @@ static const struct file_operations tracing_pipe_fops = { }; static const struct file_operations tracing_entries_fops = { - .open = tracing_open_generic_tc, + .open = tracing_open_generic_tr, .read = tracing_entries_read, .write = tracing_entries_write, .llseek = generic_file_llseek, - .release = tracing_release_generic_tc, + .release = tracing_release_generic_tr, }; static const struct file_operations tracing_total_entries_fops = { @@ -5580,7 +5555,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) tr, cpu, &tracing_stats_fops); trace_create_cpu_file("buffer_size_kb", 0444, d_cpu, - &data->trace_cpu, cpu, &tracing_entries_fops); + tr, cpu, &tracing_entries_fops); #ifdef CONFIG_TRACER_SNAPSHOT trace_create_cpu_file("snapshot", 0644, d_cpu, @@ -6156,7 +6131,7 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer) tr, &tracing_pipe_fops); trace_create_file("buffer_size_kb", 0644, d_tracer, - (void *)&tr->trace_cpu, &tracing_entries_fops); + tr, &tracing_entries_fops); trace_create_file("buffer_total_size_kb", 0444, d_tracer, tr, &tracing_total_entries_fops); -- cgit v1.2.3-70-g09d2 From 6484c71cbc170634fa131b6d022d86d61686b88b Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 23 Jul 2013 17:26:10 +0200 Subject: tracing: Change tracing_fops/snapshot_fops to rely on tracing_get_cpu() tracing_open() and tracing_snapshot_open() are racy, the memory inode->i_private points to can be already freed. Convert these last users of "inode->i_private == trace_cpu" to use "i_private = trace_array" and rely on tracing_get_cpu(). v2: incorporate the fix from Steven, tracing_release() must not blindly dereference file->private_data unless we know that the file was opened for reading. Link: http://lkml.kernel.org/r/20130723152610.GA23737@redhat.com Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 50 ++++++++++++++++++++++---------------------------- 1 file changed, 22 insertions(+), 28 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 68b46851666..dd7780ddde0 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2862,9 +2862,9 @@ static const struct seq_operations tracer_seq_ops = { }; static struct trace_iterator * -__tracing_open(struct trace_array *tr, struct trace_cpu *tc, - struct inode *inode, struct file *file, bool snapshot) +__tracing_open(struct inode *inode, struct file *file, bool snapshot) { + struct trace_array *tr = inode->i_private; struct trace_iterator *iter; int cpu; @@ -2905,8 +2905,8 @@ __tracing_open(struct trace_array *tr, struct trace_cpu *tc, iter->trace_buffer = &tr->trace_buffer; iter->snapshot = snapshot; iter->pos = -1; + iter->cpu_file = tracing_get_cpu(inode); mutex_init(&iter->mutex); - iter->cpu_file = tc->cpu; /* Notify the tracer early; before we stop tracing. */ if (iter->trace && iter->trace->open) @@ -2986,22 +2986,18 @@ static int tracing_open_generic_tr(struct inode *inode, struct file *filp) static int tracing_release(struct inode *inode, struct file *file) { + struct trace_array *tr = inode->i_private; struct seq_file *m = file->private_data; struct trace_iterator *iter; - struct trace_array *tr; int cpu; - /* Writes do not use seq_file, need to grab tr from inode */ if (!(file->f_mode & FMODE_READ)) { - struct trace_cpu *tc = inode->i_private; - - trace_array_put(tc->tr); + trace_array_put(tr); return 0; } + /* Writes do not use seq_file */ iter = m->private; - tr = iter->tr; - mutex_lock(&trace_types_lock); for_each_tracing_cpu(cpu) { @@ -3048,8 +3044,7 @@ static int tracing_single_release_tr(struct inode *inode, struct file *file) static int tracing_open(struct inode *inode, struct file *file) { - struct trace_cpu *tc = inode->i_private; - struct trace_array *tr = tc->tr; + struct trace_array *tr = inode->i_private; struct trace_iterator *iter; int ret = 0; @@ -3057,16 +3052,17 @@ static int tracing_open(struct inode *inode, struct file *file) return -ENODEV; /* If this file was open for write, then erase contents */ - if ((file->f_mode & FMODE_WRITE) && - (file->f_flags & O_TRUNC)) { - if (tc->cpu == RING_BUFFER_ALL_CPUS) + if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { + int cpu = tracing_get_cpu(inode); + + if (cpu == RING_BUFFER_ALL_CPUS) tracing_reset_online_cpus(&tr->trace_buffer); else - tracing_reset(&tr->trace_buffer, tc->cpu); + tracing_reset(&tr->trace_buffer, cpu); } if (file->f_mode & FMODE_READ) { - iter = __tracing_open(tr, tc, inode, file, false); + iter = __tracing_open(inode, file, false); if (IS_ERR(iter)) ret = PTR_ERR(iter); else if (trace_flags & TRACE_ITER_LATENCY_FMT) @@ -4680,8 +4676,7 @@ struct ftrace_buffer_info { #ifdef CONFIG_TRACER_SNAPSHOT static int tracing_snapshot_open(struct inode *inode, struct file *file) { - struct trace_cpu *tc = inode->i_private; - struct trace_array *tr = tc->tr; + struct trace_array *tr = inode->i_private; struct trace_iterator *iter; struct seq_file *m; int ret = 0; @@ -4690,7 +4685,7 @@ static int tracing_snapshot_open(struct inode *inode, struct file *file) return -ENODEV; if (file->f_mode & FMODE_READ) { - iter = __tracing_open(tr, tc, inode, file, true); + iter = __tracing_open(inode, file, true); if (IS_ERR(iter)) ret = PTR_ERR(iter); } else { @@ -4707,8 +4702,8 @@ static int tracing_snapshot_open(struct inode *inode, struct file *file) ret = 0; iter->tr = tr; - iter->trace_buffer = &tc->tr->max_buffer; - iter->cpu_file = tc->cpu; + iter->trace_buffer = &tr->max_buffer; + iter->cpu_file = tracing_get_cpu(inode); m->private = iter; file->private_data = m; } @@ -5525,7 +5520,6 @@ trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent, static void tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) { - struct trace_array_cpu *data = per_cpu_ptr(tr->trace_buffer.data, cpu); struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu); struct dentry *d_cpu; char cpu_dir[30]; /* 30 characters should be more than enough */ @@ -5546,7 +5540,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) /* per cpu trace */ trace_create_cpu_file("trace", 0644, d_cpu, - &data->trace_cpu, cpu, &tracing_fops); + tr, cpu, &tracing_fops); trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu, tr, cpu, &tracing_buffers_fops); @@ -5559,7 +5553,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) #ifdef CONFIG_TRACER_SNAPSHOT trace_create_cpu_file("snapshot", 0644, d_cpu, - &data->trace_cpu, cpu, &snapshot_fops); + tr, cpu, &snapshot_fops); trace_create_cpu_file("snapshot_raw", 0444, d_cpu, tr, cpu, &snapshot_raw_fops); @@ -6125,7 +6119,7 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer) tr, &tracing_iter_fops); trace_create_file("trace", 0644, d_tracer, - (void *)&tr->trace_cpu, &tracing_fops); + tr, &tracing_fops); trace_create_file("trace_pipe", 0444, d_tracer, tr, &tracing_pipe_fops); @@ -6146,11 +6140,11 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer) &trace_clock_fops); trace_create_file("tracing_on", 0644, d_tracer, - tr, &rb_simple_fops); + tr, &rb_simple_fops); #ifdef CONFIG_TRACER_SNAPSHOT trace_create_file("snapshot", 0644, d_tracer, - (void *)&tr->trace_cpu, &snapshot_fops); + tr, &snapshot_fops); #endif for_each_tracing_cpu(cpu) -- cgit v1.2.3-70-g09d2 From 9c01fe4593db123c5a72dc36f0400f776e92c954 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 23 Jul 2013 17:26:13 +0200 Subject: tracing: Kill trace_cpu struct/members After the previous changes trace_array_cpu->trace_cpu and trace_array->trace_cpu becomes write-only. Remove these members and kill "struct trace_cpu" as well. As a side effect this also removes memset(per_cpu_memory, 0). It was not needed, alloc_percpu() returns zero-filled memory. Link: http://lkml.kernel.org/r/20130723152613.GA23741@redhat.com Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 21 --------------------- kernel/trace/trace.h | 8 -------- 2 files changed, 29 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index dd7780ddde0..69cba470ea9 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5865,17 +5865,6 @@ struct dentry *trace_instance_dir; static void init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer); -static void init_trace_buffers(struct trace_array *tr, struct trace_buffer *buf) -{ - int cpu; - - for_each_tracing_cpu(cpu) { - memset(per_cpu_ptr(buf->data, cpu), 0, sizeof(struct trace_array_cpu)); - per_cpu_ptr(buf->data, cpu)->trace_cpu.cpu = cpu; - per_cpu_ptr(buf->data, cpu)->trace_cpu.tr = tr; - } -} - static int allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size) { @@ -5893,8 +5882,6 @@ allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size return -ENOMEM; } - init_trace_buffers(tr, buf); - /* Allocate the first page for all buffers */ set_buffer_entries(&tr->trace_buffer, ring_buffer_size(tr->trace_buffer.buffer, 0)); @@ -5961,10 +5948,6 @@ static int new_instance_create(const char *name) if (allocate_trace_buffers(tr, trace_buf_size) < 0) goto out_free_tr; - /* Holder for file callbacks */ - tr->trace_cpu.cpu = RING_BUFFER_ALL_CPUS; - tr->trace_cpu.tr = tr; - tr->dir = debugfs_create_dir(name, trace_instance_dir); if (!tr->dir) goto out_free_tr; @@ -6438,10 +6421,6 @@ __init static int tracer_alloc_buffers(void) global_trace.flags = TRACE_ARRAY_FL_GLOBAL; - /* Holder for file callbacks */ - global_trace.trace_cpu.cpu = RING_BUFFER_ALL_CPUS; - global_trace.trace_cpu.tr = &global_trace; - INIT_LIST_HEAD(&global_trace.systems); INIT_LIST_HEAD(&global_trace.events); list_add(&global_trace.list, &ftrace_trace_arrays); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index e7d643b8a90..afaae41b0a0 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -130,19 +130,12 @@ enum trace_flag_type { struct trace_array; -struct trace_cpu { - struct trace_array *tr; - struct dentry *dir; - int cpu; -}; - /* * The CPU trace array - it consists of thousands of trace entries * plus some other descriptor data: (for example which task started * the trace, etc.) */ struct trace_array_cpu { - struct trace_cpu trace_cpu; atomic_t disabled; void *buffer_page; /* ring buffer spare */ @@ -196,7 +189,6 @@ struct trace_array { bool allocated_snapshot; #endif int buffer_disabled; - struct trace_cpu trace_cpu; /* place holder */ #ifdef CONFIG_FTRACE_SYSCALLS int sys_refcount_enter; int sys_refcount_exit; -- cgit v1.2.3-70-g09d2 From 09d8091c024ec88d1541d93eb8ddb2bd5cf10c39 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Tue, 23 Jul 2013 22:21:59 -0400 Subject: tracing: Remove locking trace_types_lock from tracing_reset_all_online_cpus() Commit a82274151af "tracing: Protect ftrace_trace_arrays list in trace_events.c" added taking the trace_types_lock mutex in trace_events.c as there were several locations that needed it for protection. Unfortunately, it also encapsulated a call to tracing_reset_all_online_cpus() which also takes the trace_types_lock, causing a deadlock. This happens when a module has tracepoints and has been traced. When the module is removed, the trace events module notifier will grab the trace_types_lock, do a bunch of clean ups, and also clears the buffer by calling tracing_reset_all_online_cpus. This doesn't happen often which explains why it wasn't caught right away. Commit a82274151af was marked for stable, which means this must be sent to stable too. Link: http://lkml.kernel.org/r/51EEC646.7070306@broadcom.com Reported-by: Arend van Spril Tested-by: Arend van Spriel Cc: Alexander Z Lam Cc: Vaibhav Nagarnaik Cc: David Sharp Cc: stable@vger.kernel.org # 3.10 Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 69cba470ea9..882ec1dd151 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1224,18 +1224,17 @@ void tracing_reset_current(int cpu) tracing_reset(&global_trace.trace_buffer, cpu); } +/* Must have trace_types_lock held */ void tracing_reset_all_online_cpus(void) { struct trace_array *tr; - mutex_lock(&trace_types_lock); list_for_each_entry(tr, &ftrace_trace_arrays, list) { tracing_reset_online_cpus(&tr->trace_buffer); #ifdef CONFIG_TRACER_MAX_TRACE tracing_reset_online_cpus(&tr->max_buffer); #endif } - mutex_unlock(&trace_types_lock); } #define SAVED_CMDLINES 128 -- cgit v1.2.3-70-g09d2 From ed5467da0e369e65b247b99eb6403cb79172bcda Mon Sep 17 00:00:00 2001 From: Andrew Vagin Date: Fri, 2 Aug 2013 21:16:43 +0400 Subject: tracing: Fix fields of struct trace_iterator that are zeroed by mistake tracing_read_pipe zeros all fields bellow "seq". The declaration contains a comment about that, but it doesn't help. The first field is "snapshot", it's true when current open file is snapshot. Looks obvious, that it should not be zeroed. The second field is "started". It was converted from cpumask_t to cpumask_var_t (v2.6.28-4983-g4462344), in other words it was converted from cpumask to pointer on cpumask. Currently the reference on "started" memory is lost after the first read from tracing_read_pipe and a proper object will never be freed. The "started" is never dereferenced for trace_pipe, because trace_pipe can't have the TRACE_FILE_ANNOTATE options. Link: http://lkml.kernel.org/r/1375463803-3085183-1-git-send-email-avagin@openvz.org Cc: stable@vger.kernel.org # 2.6.30 Signed-off-by: Andrew Vagin Signed-off-by: Steven Rostedt --- include/linux/ftrace_event.h | 10 ++++++---- kernel/trace/trace.c | 1 + 2 files changed, 7 insertions(+), 4 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index f98ab063e95..120d57a1c3a 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -78,6 +78,11 @@ struct trace_iterator { /* trace_seq for __print_flags() and __print_symbolic() etc. */ struct trace_seq tmp_seq; + cpumask_var_t started; + + /* it's true when current open file is snapshot */ + bool snapshot; + /* The below is zeroed out in pipe_read */ struct trace_seq seq; struct trace_entry *ent; @@ -90,10 +95,7 @@ struct trace_iterator { loff_t pos; long idx; - cpumask_var_t started; - - /* it's true when current open file is snapshot */ - bool snapshot; + /* All new field here will be zeroed out in pipe_read */ }; enum trace_iter_flags { diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 882ec1dd151..f5b35a5e852 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4151,6 +4151,7 @@ waitagain: memset(&iter->seq, 0, sizeof(struct trace_iterator) - offsetof(struct trace_iterator, seq)); + cpumask_clear(iter->started); iter->pos = -1; trace_event_read_lock(); -- cgit v1.2.3-70-g09d2 From 711e124379e0f889e40e2f01d7f5d61936d3cd23 Mon Sep 17 00:00:00 2001 From: Alexander Z Lam Date: Fri, 2 Aug 2013 18:36:15 -0700 Subject: tracing: Make TRACE_ITER_STOP_ON_FREE stop the correct buffer Releasing the free_buffer file in an instance causes the global buffer to be stopped when TRACE_ITER_STOP_ON_FREE is enabled. Operate on the correct buffer. Link: http://lkml.kernel.org/r/1375493777-17261-1-git-send-email-azl@google.com Cc: Vaibhav Nagarnaik Cc: David Sharp Cc: Alexander Z Lam Cc: stable@vger.kernel.org # 3.10 Signed-off-by: Alexander Z Lam Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index f5b35a5e852..531c9e69d0b 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4469,7 +4469,7 @@ tracing_free_buffer_release(struct inode *inode, struct file *filp) /* disable tracing ? */ if (trace_flags & TRACE_ITER_STOP_ON_FREE) - tracing_off(); + tracer_tracing_off(tr); /* resize the ring buffer to 0 */ tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS); -- cgit v1.2.3-70-g09d2 From 9457158bbc0ee04ecef76862d73eecd8076e9c7b Mon Sep 17 00:00:00 2001 From: Alexander Z Lam Date: Fri, 2 Aug 2013 18:36:16 -0700 Subject: tracing: Fix reset of time stamps during trace_clock changes Fixed two issues with changing the timestamp clock with trace_clock: - The global buffer was reset on instance clock changes. Change this to pass the correct per-instance buffer - ftrace_now() is used to set buf->time_start in tracing_reset_online_cpus(). This was incorrect because ftrace_now() used the global buffer's clock to return the current time. Change this to use buffer_ftrace_now() which returns the current time for the correct per-instance buffer. Also removed tracing_reset_current() because it is not used anywhere Link: http://lkml.kernel.org/r/1375493777-17261-2-git-send-email-azl@google.com Cc: Vaibhav Nagarnaik Cc: David Sharp Cc: Alexander Z Lam Cc: stable@vger.kernel.org # 3.10 Signed-off-by: Alexander Z Lam Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 531c9e69d0b..496f94d5769 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -243,20 +243,25 @@ int filter_current_check_discard(struct ring_buffer *buffer, } EXPORT_SYMBOL_GPL(filter_current_check_discard); -cycle_t ftrace_now(int cpu) +cycle_t buffer_ftrace_now(struct trace_buffer *buf, int cpu) { u64 ts; /* Early boot up does not have a buffer yet */ - if (!global_trace.trace_buffer.buffer) + if (!buf->buffer) return trace_clock_local(); - ts = ring_buffer_time_stamp(global_trace.trace_buffer.buffer, cpu); - ring_buffer_normalize_time_stamp(global_trace.trace_buffer.buffer, cpu, &ts); + ts = ring_buffer_time_stamp(buf->buffer, cpu); + ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts); return ts; } +cycle_t ftrace_now(int cpu) +{ + return buffer_ftrace_now(&global_trace.trace_buffer, cpu); +} + /** * tracing_is_enabled - Show if global_trace has been disabled * @@ -1211,7 +1216,7 @@ void tracing_reset_online_cpus(struct trace_buffer *buf) /* Make sure all commits have finished */ synchronize_sched(); - buf->time_start = ftrace_now(buf->cpu); + buf->time_start = buffer_ftrace_now(buf, buf->cpu); for_each_online_cpu(cpu) ring_buffer_reset_cpu(buffer, cpu); @@ -1219,11 +1224,6 @@ void tracing_reset_online_cpus(struct trace_buffer *buf) ring_buffer_record_enable(buffer); } -void tracing_reset_current(int cpu) -{ - tracing_reset(&global_trace.trace_buffer, cpu); -} - /* Must have trace_types_lock held */ void tracing_reset_all_online_cpus(void) { @@ -4634,12 +4634,12 @@ static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf, * New clock may not be consistent with the previous clock. * Reset the buffer so that it doesn't have incomparable timestamps. */ - tracing_reset_online_cpus(&global_trace.trace_buffer); + tracing_reset_online_cpus(&tr->trace_buffer); #ifdef CONFIG_TRACER_MAX_TRACE if (tr->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer) ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func); - tracing_reset_online_cpus(&global_trace.max_buffer); + tracing_reset_online_cpus(&tr->max_buffer); #endif mutex_unlock(&trace_types_lock); -- cgit v1.2.3-70-g09d2