From 2824f5033248600673e3e126a4d135363cbfd9ac Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Mon, 28 May 2018 10:56:36 -0400 Subject: 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) --- kernel/trace/trace.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'kernel/trace/trace.h') 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 */ -- cgit v1.2.3