perf/core: Exit early on perf_mmap() fail

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.com>Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/events/core.c b/kernel/events/core.c
index b606680370caec1b905f1110e251fc868d3e311c..92ed4b5b0b8bab58dab401d8621526757fcaf8fe 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6836,6 +6836,9 @@ 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.