From: Steven Rostedt (Google) <rostedt@goodmis.org>
Date: Sat, 30 Sep 2023 13:01:06 +0000 (-0400)
Subject: eventfs: Test for dentries array allocated in eventfs_release()
X-Git-Tag: v6.6.17~3828^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2598bd3ca8dcf5bbca1161ee5b271b432398da37;p=platform%2Fkernel%2Flinux-rpi.git

eventfs: Test for dentries array allocated in eventfs_release()

The dcache_dir_open_wrapper() could be called when a dynamic event is
being deleted leaving a dentry with no children. In this case the
dlist->dentries array will never be allocated. This needs to be checked
for in eventfs_release(), otherwise it will trigger a NULL pointer
dereference.

Link: https://lore.kernel.org/linux-trace-kernel/20230930090106.1c3164e9@rorschach.local.home

Cc: Mark Rutland <mark.rutland@arm.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Fixes: ef36b4f92868 ("eventfs: Remember what dentries were created on dir open")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 5f17140..8c8d64e 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -421,7 +421,7 @@ static int eventfs_release(struct inode *inode, struct file *file)
 	if (WARN_ON_ONCE(!dlist))
 		return -EINVAL;
 
-	for (i = 0; dlist->dentries[i]; i++) {
+	for (i = 0; dlist->dentries && dlist->dentries[i]; i++) {
 		dput(dlist->dentries[i]);
 	}