From: Thomas Gleixner <tglx@linutronix.de>
Date: Sat, 2 Aug 2025 10:49:48 +0000 (+0200)
Subject: perf/core: Exit early on perf_mmap() fail
X-Git-Tag: v6.1.148~20
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=27d44145bd576bbef9bf6165bcd78128ec3e6cbd;p=thirdparty%2Fkernel%2Fstable.git

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 1c3a436988bc9..21b37c2147611 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6504,6 +6504,9 @@ 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.