From 8b6c58458ee3206dde345fce327a4cb83e69caf9 Mon Sep 17 00:00:00 2001 From: Ronnie Sahlberg Date: Wed, 13 Apr 2022 10:02:17 +1000 Subject: [PATCH] cifs: verify that tcon is valid before dereference in cifs_kill_sb On umount, cifs_sb->tlink_tree might contain entries that do not represent a valid tcon. Check the tcon for error before we dereference it. Signed-off-by: Ronnie Sahlberg Cc: stable@vger.kernel.org Reviewed-by: Shyam Prasad N Reported-by: Xiaoli Feng Signed-off-by: Steve French --- fs/cifs/cifsfs.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index aba0783..2b1a1c0 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -266,10 +266,11 @@ static void cifs_kill_sb(struct super_block *sb) * before we kill the sb. */ if (cifs_sb->root) { - node = rb_first(root); - while (node != NULL) { + for (node = rb_first(root); node; node = rb_next(node)) { tlink = rb_entry(node, struct tcon_link, tl_rbnode); tcon = tlink_tcon(tlink); + if (IS_ERR(tcon)) + continue; cfid = &tcon->crfid; mutex_lock(&cfid->fid_mutex); if (cfid->dentry) { @@ -277,7 +278,6 @@ static void cifs_kill_sb(struct super_block *sb) cfid->dentry = NULL; } mutex_unlock(&cfid->fid_mutex); - node = rb_next(node); } /* finally release root dentry */ -- 2.7.4