linux-kernel - [tip:perf/urgent] perf/core: Fix creating kernel counters for PMUs that override event->cpu

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Date:   Thu, 25 Jul 2019 09:07:52 -0700
From:   tip-bot for Leonard Crestez <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     tglx@...utronix.de, hpa@...or.com, jolsa@...hat.com,
        mingo@...nel.org, acme@...nel.org, linux-kernel@...r.kernel.org,
        Frank.li@....com, namhyung@...nel.org, peterz@...radead.org,
        leonard.crestez@....com, alexander.shishkin@...ux.intel.com,
        mark.rutland@....com, torvalds@...ux-foundation.org,
        will@...nel.org
Subject: [tip:perf/urgent] perf/core: Fix creating kernel counters for PMUs
 that override event->cpu

Commit-ID:  4ce54af8b33d3e21ca935fc1b89b58cbba956051
Gitweb:     https://git.kernel.org/tip/4ce54af8b33d3e21ca935fc1b89b58cbba956051
Author:     Leonard Crestez <leonard.crestez@....com>
AuthorDate: Wed, 24 Jul 2019 15:53:24 +0300
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Thu, 25 Jul 2019 15:41:31 +0200

perf/core: Fix creating kernel counters for PMUs that override event->cpu

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@....com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Mark Rutland <mark.rutland@....com>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Frank Li <Frank.li@....com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Will Deacon <will@...nel.org>
Link: https://lkml.kernel.org/r/c4ebe0503623066896d7046def4d6b1e06e0eb2e.1563972056.git.leonard.crestez@nxp.com
Signed-off-by: Ingo Molnar <mingo@...nel.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 026a14541a38..0463c1151bae 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11274,7 +11274,7 @@ 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);