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author | Takashi Iwai | 2010-12-13 09:29:52 +0100 |
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committer | Takashi Iwai | 2010-12-13 09:29:52 +0100 |
commit | 354d14b3f53cc749c5d26d4ba7280d1e931d6bc4 (patch) | |
tree | 59b597e44902d8db8bde7deac1e7e707327c6fe6 /kernel/trace/trace.c | |
parent | ALSA: aoa: Remove wrong i2c_set_clientdata in onyx_i2c_remove() (diff) | |
parent | sound: don't use flush_scheduled_work() (diff) | |
download | kernel-qcow2-linux-354d14b3f53cc749c5d26d4ba7280d1e931d6bc4.tar.gz kernel-qcow2-linux-354d14b3f53cc749c5d26d4ba7280d1e931d6bc4.tar.xz kernel-qcow2-linux-354d14b3f53cc749c5d26d4ba7280d1e931d6bc4.zip |
Merge branch 'topic/workq-update' into topic/misc
Diffstat (limited to 'kernel/trace/trace.c')
-rw-r--r-- | kernel/trace/trace.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 82d9b8106cd0..c380612273bf 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -17,7 +17,6 @@ #include <linux/writeback.h> #include <linux/kallsyms.h> #include <linux/seq_file.h> -#include <linux/smp_lock.h> #include <linux/notifier.h> #include <linux/irqflags.h> #include <linux/debugfs.h> @@ -1284,6 +1283,8 @@ void trace_dump_stack(void) __ftrace_trace_stack(global_trace.buffer, flags, 3, preempt_count()); } +static DEFINE_PER_CPU(int, user_stack_count); + void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) { @@ -1302,6 +1303,18 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) if (unlikely(in_nmi())) return; + /* + * prevent recursion, since the user stack tracing may + * trigger other kernel events. + */ + preempt_disable(); + if (__this_cpu_read(user_stack_count)) + goto out; + + __this_cpu_inc(user_stack_count); + + + event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK, sizeof(*entry), flags, pc); if (!event) @@ -1319,6 +1332,11 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) save_stack_trace_user(&trace); if (!filter_check_discard(call, entry, buffer, event)) ring_buffer_unlock_commit(buffer, event); + + __this_cpu_dec(user_stack_count); + + out: + preempt_enable(); } #ifdef UNUSED |