From: Tetsuo Handa
stable inclusion
from stable-5.10
category: feature
commit:a7acb614287b7de8bf86d6758dac43bbd1d29534
issue: #I4919J
--------------------------------
commit 9c7d83ae6ba67d6c6199cce24573983db3b56332 upstream.
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=6abacb8da5137cb47a416f2bef95719ed60508a...
Reported-by: syzbot
Signed-off-by: Tetsuo Handa
Signed-off-by: Kees Cook
Link: https://lore.kernel.org/r/20210214031307.57903-1-penguin-kernel@I-love.SAKUR...
Signed-off-by: Greg Kroah-Hartman
(cherry picked from commit a7acb614287b7de8bf86d6758dac43bbd1d29534)
Signed-off-by: roger
---
fs/pstore/inode.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index b4836705d220..7e45ff1f8a39 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -448,7 +448,7 @@ 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;
--
2.17.1
