6.15-stable review patch. If anyone has any objections, please let me know.
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From: Thomas Gleixner tglx@linutronix.de
commit 07091aade394f690e7b655578140ef84d0e8d7b0 upstream.
When perf_mmap() fails to allocate a buffer, it still invokes the event_mapped() callback of the related event. On X86 this might increase the perf_rdpmc_allowed reference counter. But nothing undoes this as perf_mmap_close() is never called in this case, which causes another reference count leak.
Return early on failure to prevent that.
Fixes: 1e0fb9ec679c ("perf/core: Add pmu callbacks to track event mapping and unmapping") Signed-off-by: Thomas Gleixner tglx@linutronix.de Reviewed-by: Lorenzo Stoakes lorenzo.stoakes@oracle.comCc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/events/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7075,6 +7075,9 @@ aux_unlock: mutex_unlock(aux_mutex); mutex_unlock(&event->mmap_mutex);
+ if (ret) + return ret; + /* * Since pinned accounting is per vm we cannot allow fork() to copy our * vma. @@ -7082,8 +7085,7 @@ aux_unlock: vm_flags_set(vma, VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP); vma->vm_ops = &perf_mmap_vmops;
- if (!ret) - ret = map_range(rb, vma); + ret = map_range(rb, vma);
if (!ret && event->pmu->event_mapped) event->pmu->event_mapped(event, vma->vm_mm);