From: Dongliang Mu mudongliangabcd@gmail.com
[ Upstream commit a942da24abc5839c11a8fc2a4b7cb268ea94ba54 ]
Syzkaller hit 'WARNING: kobject bug in erofs_unregister_sysfs'. This bug is triggered by injecting fault in kobject_init_and_add of erofs_unregister_sysfs.
Fix this by adding sanity check for kobject in erofs_unregister_sysfs
Note that I've tested the patch and the crash does not occur any more.
Link: https://lore.kernel.org/r/20220315132814.12332-1-dzm91@hust.edu.cn Signed-off-by: Dongliang Mu mudongliangabcd@gmail.com Fixes: 168e9a76200c ("erofs: add sysfs interface") Reviewed-by: Gao Xiang hsiangkao@linux.alibaba.com Reviewed-by: Chao Yu chao@kernel.org Signed-off-by: Gao Xiang hsiangkao@linux.alibaba.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/erofs/sysfs.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/erofs/sysfs.c b/fs/erofs/sysfs.c index dac252bc9228..f3babf1e6608 100644 --- a/fs/erofs/sysfs.c +++ b/fs/erofs/sysfs.c @@ -221,9 +221,11 @@ void erofs_unregister_sysfs(struct super_block *sb) { struct erofs_sb_info *sbi = EROFS_SB(sb);
- kobject_del(&sbi->s_kobj); - kobject_put(&sbi->s_kobj); - wait_for_completion(&sbi->s_kobj_unregister); + if (sbi->s_kobj.state_in_sysfs) { + kobject_del(&sbi->s_kobj); + kobject_put(&sbi->s_kobj); + wait_for_completion(&sbi->s_kobj_unregister); + } }
int __init erofs_init_sysfs(void)