perf: fix perf_event_context->time
authorSong Liu <song@kernel.org>
Mon, 13 Mar 2023 17:16:08 +0000 (10:16 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 30 Mar 2023 10:48:59 +0000 (12:48 +0200)
commitd496185c25a600f4e6059fea105f5eca2ab79440
treea0ced1e3136147be83e604dce6675c00176cee7d
parentff8137727a2af4ad5f6e6c8b9f7ec5e8db9da86c
perf: fix perf_event_context->time

[ Upstream commit baf1b12a67f5b24f395baca03e442ce27cab0c18 ]

Time readers rely on perf_event_context->[time|timestamp|timeoffset] to get
accurate time_enabled and time_running for an event. The difference between
ctx->timestamp and ctx->time is the among of time when the context is not
enabled. __update_context_time(ctx, false) is used to increase timestamp,
but not time. Therefore, it should only be called in ctx_sched_in() when
EVENT_TIME was not enabled.

Fixes: 09f5e7dc7ad7 ("perf: Fix perf_event_read_local() time")
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/r/20230313171608.298734-1-song@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
kernel/events/core.c