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perf/core: Exit early on perf_mmap() fail 

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: 1e0fb9ec67 ("perf: Add pmu callbacks to track event mapping and unmapping")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: stable@vger.kernel.org
This commit is contained in:
Thomas Gleixner 2025-08-02 12:49:48 +02:00
parent 5468c0fbcc
commit 07091aade3
1 changed files with 4 additions and 2 deletions
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4
kernel/events/core.c
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@ -7138,6 +7138,9 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
mutex_unlock(aux_mutex); mutex_unlock(aux_mutex);
mutex_unlock(&event->mmap_mutex); mutex_unlock(&event->mmap_mutex);
if (ret)
return ret;
/* /*
* Since pinned accounting is per vm we cannot allow fork() to copy our * Since pinned accounting is per vm we cannot allow fork() to copy our
* vma. * vma.
@ -7145,7 +7148,6 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
vm_flags_set(vma, VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP); vm_flags_set(vma, VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP);
vma->vm_ops = &perf_mmap_vmops; vma->vm_ops = &perf_mmap_vmops;
if (!ret)
ret = map_range(rb, vma); ret = map_range(rb, vma);
mapped = get_mapped(event, event_mapped); mapped = get_mapped(event, event_mapped);