Messages in this thread | | | From | James Clark <> | Subject | [PATCH 0/1] perf: Fix warning from concurrent read/write of perf_event_pmu_context | Date | Fri, 27 Jan 2023 14:31:40 +0000 |
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Hi Peter and Ravi,
I came across this issue, and I also found there was a syzbot report for it and linked it on the commit. I have one question about the fix, where I had to remove the if (epc->ctx) from put_pmu_ctx(). I assume this was added for a reason, but I can't see where it's not ever set? Unless it's removed, the function got a lot more complicated to take the lock before the reference decrement.
Also now I think the atomic type for epc->refcount is redundant, because everything is always done with the lock held. Except for get_pmu_ctx(), but that is just a read for a warning. So unless you think the scope of my extra locking can be reduced, I would probably also send a commit to remove that as well.
Thanks James
James Clark (1): perf: Fix warning from concurrent read/write of perf_event_pmu_context
kernel/events/core.c | 42 ++++++++++++++++++++---------------------- 1 file changed, 20 insertions(+), 22 deletions(-)
base-commit: 5912e15f25d6d584f3b8449e0b6a244a0f4f0903 -- 2.39.1
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