kernel_optimize_test/kernel/events
Peter Zijlstra 94902ee299 perf: Rework perf_event_exit_event()
[ Upstream commit ef54c1a476aef7eef26fe13ea10dc090952c00f8 ]

Make perf_event_exit_event() more robust, such that we can use it from
other contexts. Specifically the up and coming remove_on_exec.

For this to work we need to address a few issues. Remove_on_exec will
not destroy the entire context, so we cannot rely on TASK_TOMBSTONE to
disable event_function_call() and we thus have to use
perf_remove_from_context().

When using perf_remove_from_context(), there's two races to consider.
The first is against close(), where we can have concurrent tear-down
of the event. The second is against child_list iteration, which should
not find a half baked event.

To address this, teach perf_remove_from_context() to special case
!ctx->is_active and about DETACH_CHILD.

[ elver@google.com: fix racing parent/child exit in sync_child_event(). ]
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210408103605.1676875-2-elver@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-11 14:47:31 +02:00
..
callchain.c uaccess: add force_uaccess_{begin,end} helpers 2020-08-12 10:57:59 -07:00
core.c perf: Rework perf_event_exit_event() 2021-05-11 14:47:31 +02:00
hw_breakpoint.c powerpc/watchpoint: Don't allow concurrent perf and ptrace events 2020-05-19 00:14:45 +10:00
internal.h perf: Optimize get_recursion_context() 2020-11-09 18:12:34 +01:00
Makefile
ring_buffer.c perf: Reduce stack usage of perf_output_begin() 2020-11-09 18:12:33 +01:00
uprobes.c task_work: cleanup notification modes 2020-10-17 15:05:30 -06:00