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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2021-02-14 12:13:07 +0900
committerKees Cook <keescook@chromium.org>2021-02-23 09:27:20 -0800
commit9c7d83ae6ba67d6c6199cce24573983db3b56332 (patch)
tree5ab82c34cfd2fc3a9fba8d9aa9d3e33b26902e1a /fs/pstore
parent19d8e9149c27b689c6224f5c84b96a159342195a (diff)
downloadlinux-9c7d83ae6ba67d6c6199cce24573983db3b56332.tar.gz
pstore: Fix warning in pstore_kill_sb()
syzbot is hitting WARN_ON(pstore_sb != sb) at pstore_kill_sb() [1], for the
assumption that pstore_sb != NULL is wrong because pstore_fill_super() will
not assign pstore_sb = sb when new_inode() for d_make_root() returned NULL
(due to memory allocation fault injection).

Since mount_single() calls pstore_kill_sb() when pstore_fill_super()
failed, pstore_kill_sb() needs to be aware of such failure path.

[1] https://syzkaller.appspot.com/bug?id=6abacb8da5137cb47a416f2bef95719ed60508a0

Reported-by: syzbot <syzbot+d0cf0ad6513e9a1da5df@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210214031307.57903-1-penguin-kernel@I-love.SAKURA.ne.jp
Diffstat (limited to 'fs/pstore')
-rw-r--r--fs/pstore/inode.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 93a217e4f563..14658b009f1b 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -467,7 +467,7 @@ static struct dentry *pstore_mount(struct file_system_type *fs_type,
 static void pstore_kill_sb(struct super_block *sb)
 {
 	mutex_lock(&pstore_sb_lock);
-	WARN_ON(pstore_sb != sb);
+	WARN_ON(pstore_sb && pstore_sb != sb);
 
 	kill_litter_super(sb);
 	pstore_sb = NULL;