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| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2018-05-28 16:56:36 +0200 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2018-05-28 18:49:32 +0200 |
| commit | 2824f5033248600673e3e126a4d135363cbfd9ac (patch) | |
| tree | 17fe738bb43eccf32b2827f5abd814a3b91e1b29 /kernel/trace/trace.h | |
| parent | tracing: Fix crash when freeing instances with event triggers (diff) | |
| download | linux-2824f5033248600673e3e126a4d135363cbfd9ac.tar.xz linux-2824f5033248600673e3e126a4d135363cbfd9ac.zip | |
tracing: Make the snapshot trigger work with instances
The snapshot trigger currently only affects the main ring buffer, even when
it is used by the instances. This can be confusing as the snapshot trigger
is listed in the instance.
> # cd /sys/kernel/tracing
> # mkdir instances/foo
> # echo snapshot > instances/foo/events/syscalls/sys_enter_fchownat/trigger
> # echo top buffer > trace_marker
> # echo foo buffer > instances/foo/trace_marker
> # touch /tmp/bar
> # chown rostedt /tmp/bar
> # cat instances/foo/snapshot
# tracer: nop
#
#
# * Snapshot is freed *
#
# Snapshot commands:
# echo 0 > snapshot : Clears and frees snapshot buffer
# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.
# Takes a snapshot of the main buffer.
# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)
# (Doesn't have to be '2' works with any number that
# is not a '0' or '1')
> # cat snapshot
# tracer: nop
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
bash-1189 [000] .... 111.488323: tracing_mark_write: top buffer
Not only did the snapshot occur in the top level buffer, but the instance
snapshot buffer should have been allocated, and it is still free.
Cc: stable@vger.kernel.org
Fixes: 85f2b08268c01 ("tracing: Add basic event trigger framework")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace.h')
| -rw-r--r-- | kernel/trace/trace.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 6fb46a06c9dc..507954b4e058 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1817,6 +1817,17 @@ static inline void __init trace_event_init(void) { } static inline void trace_event_eval_update(struct trace_eval_map **map, int len) { } #endif +#ifdef CONFIG_TRACER_SNAPSHOT +void tracing_snapshot_instance(struct trace_array *tr); +int tracing_alloc_snapshot_instance(struct trace_array *tr); +#else +static inline void tracing_snapshot_instance(struct trace_array *tr) { } +static inline int tracing_alloc_snapshot_instance(struct trace_array *tr) +{ + return 0; +} +#endif + extern struct trace_iterator *tracepoint_print_iter; #endif /* _LINUX_KERNEL_TRACE_H */ |