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Subject[PATCH AUTOSEL 4.9 22/22] perf/core: Fix creating kernel counters for PMUs that override event->cpu
Date
From: Leonard Crestez <leonard.crestez@nxp.com>

[ Upstream commit 4ce54af8b33d3e21ca935fc1b89b58cbba956051 ]

Some hardware PMU drivers will override perf_event.cpu inside their
event_init callback. This causes a lockdep splat when initialized through
the kernel API:

WARNING: CPU: 0 PID: 250 at kernel/events/core.c:2917 ctx_sched_out+0x78/0x208
pc : ctx_sched_out+0x78/0x208
Call trace:
ctx_sched_out+0x78/0x208
__perf_install_in_context+0x160/0x248
remote_function+0x58/0x68
generic_exec_single+0x100/0x180
smp_call_function_single+0x174/0x1b8
perf_install_in_context+0x178/0x188
perf_event_create_kernel_counter+0x118/0x160

Fix this by calling perf_install_in_context with event->cpu, just like
perf_event_open

Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Frank Li <Frank.li@nxp.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Link: https://lkml.kernel.org/r/c4ebe0503623066896d7046def4d6b1e06e0eb2e.1563972056.git.leonard.crestez@nxp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/events/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 93d7333c64d89..5bbf7537a6121 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10130,7 +10130,7 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
goto err_unlock;
}

- perf_install_in_context(ctx, event, cpu);
+ perf_install_in_context(ctx, event, event->cpu);
perf_unpin_context(ctx);
mutex_unlock(&ctx->mutex);

--
2.20.1
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