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| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2016-05-25 14:03:50 +0200 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2017-11-23 00:49:47 -0500 |
| commit | 59f0482a8045c438eee8c1e42cea167164726a62 (patch) | |
| tree | a2e54c0b5efc1d703790f50570d524a0bb821bb7 | |
| parent | 7ab3b071b0f75ddd12af6b6e4d96d12e8ca3fd0d (diff) | |
| download | linux-rt-59f0482a8045c438eee8c1e42cea167164726a62.tar.gz | |
trace: correct off by one while recording the trace-event
Trace events like raw_syscalls show always a preempt code of one. The
reason is that on PREEMPT kernels rcu_read_lock_sched_notrace()
increases the preemption counter and the function recording the counter
is caller within the RCU section.
Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
[ Changed this to upstream version. See commit e947841c0dce ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| -rw-r--r-- | include/trace/ftrace.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 763bf05ccb27..73aab555b42d 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -530,6 +530,9 @@ ftrace_raw_event_##call(void *__data, proto) \ \ local_save_flags(irq_flags); \ pc = preempt_count(); \ + /* Account for tracepoint preempt disable */ \ + if (IS_ENABLED(CONFIG_PREEMPT)) \ + pc--; \ \ __data_size = ftrace_get_offsets_##call(&__data_offsets, args); \ \ |