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| author | Peter Zijlstra <peterz@infradead.org> | 2024-11-04 14:39:11 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-03-13 12:58:29 +0100 |
| commit | 7c823e4c30d6fdc16089e13924260086eaea76be (patch) | |
| tree | 0ae5c3bf61a89b5ebf5658a976237fa02c9b91ae /kernel | |
| parent | 90d302619ee7ce5ed0c69c29c290bdccfde66418 (diff) | |
| download | linux-7c823e4c30d6fdc16089e13924260086eaea76be.tar.gz linux-7c823e4c30d6fdc16089e13924260086eaea76be.tar.bz2 linux-7c823e4c30d6fdc16089e13924260086eaea76be.zip | |
perf/core: Fix pmus_lock vs. pmus_srcu ordering
[ Upstream commit 2565e42539b120b81a68a58da961ce5d1e34eac8 ]
Commit a63fbed776c7 ("perf/tracing/cpuhotplug: Fix locking order")
placed pmus_lock inside pmus_srcu, this makes perf_pmu_unregister()
trip lockdep.
Move the locking about such that only pmu_idr and pmus (list) are
modified while holding pmus_lock. This avoids doing synchronize_srcu()
while holding pmus_lock and all is well again.
Fixes: a63fbed776c7 ("perf/tracing/cpuhotplug: Fix locking order")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20241104135517.679556858@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/core.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 4f6b18ecfdb2..4dd8936b5aa0 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11660,6 +11660,8 @@ void perf_pmu_unregister(struct pmu *pmu) { mutex_lock(&pmus_lock); list_del_rcu(&pmu->entry); + idr_remove(&pmu_idr, pmu->type); + mutex_unlock(&pmus_lock); /* * We dereference the pmu list under both SRCU and regular RCU, so @@ -11669,7 +11671,6 @@ void perf_pmu_unregister(struct pmu *pmu) synchronize_rcu(); free_percpu(pmu->pmu_disable_count); - idr_remove(&pmu_idr, pmu->type); if (pmu_bus_running && pmu->dev && pmu->dev != PMU_NULL_DEV) { if (pmu->nr_addr_filters) device_remove_file(pmu->dev, &dev_attr_nr_addr_filters); @@ -11677,7 +11678,6 @@ void perf_pmu_unregister(struct pmu *pmu) put_device(pmu->dev); } free_pmu_context(pmu); - mutex_unlock(&pmus_lock); } EXPORT_SYMBOL_GPL(perf_pmu_unregister); |