Commit 07091aad authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

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: 1e0fb9ec ("perf: Add pmu callbacks to track event mapping and unmapping")
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarLorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: stable@vger.kernel.org
parent 5468c0fb

kernel/events/core.c

+4 −2
Original line number Diff line number Diff line
@@ -7138,6 +7138,9 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) 
		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.
@@ -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);

	vma->vm_ops = &perf_mmap_vmops;



	if (!ret)

	ret = map_range(rb, vma);



	mapped = get_mapped(event, event_mapped);