Commit-ID: 27ca9236c96f4a21b72a2b4f08260efeab951bd0
Gitweb: http://git.kernel.org/tip/27ca9236c96f4a21b72a2b4f08260efeab951bd0
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Tue, 9 Feb 2016 20:11:26 +0000
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 17 Feb 2016 10:37:29 +0100
perf/core: Remove the bogus and dangerous CPU_DOWN_FAILED hotplug state
If CPU_DOWN_PREPARE fails the perf hotplug notifier is called for
CPU_DOWN_FAILED and calls perf_event_init_cpu(), which checks whether the
swhash is referenced. If yes it allocates a new hash and stores the pointer in
the per cpu data structure.
But at this point the cpu is still online, so there must be a valid hash
already. By overwriting the pointer the existing hash is not longer
accessible.
Remove the CPU_DOWN_FAILED state, as there is nothing to (re)allocate.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
Link: http://lkml.kernel.org/r/20160209201007.763417379@xxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/events/core.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 474ffea..4aa64a8 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9282,7 +9282,6 @@ perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_UP_PREPARE:
- case CPU_DOWN_FAILED:
perf_event_init_cpu(cpu);
break;
--
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