From: Dongliang Mu <[email protected]> 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 remembering if kobject_init_and_add is successful. Note that I've tested the patch and the crash does not occur any more. Reported-by: syzkaller <[email protected]> Signed-off-by: Dongliang Mu <[email protected]> --- fs/erofs/internal.h | 1 + fs/erofs/sysfs.c | 9 ++++++--- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h index 5aa2cf2c2f80..9e20665e3f68 100644 --- a/fs/erofs/internal.h +++ b/fs/erofs/internal.h @@ -144,6 +144,7 @@ struct erofs_sb_info { u32 feature_incompat; /* sysfs support */ + bool s_sysfs_inited; struct kobject s_kobj; /* /sys/fs/erofs/<devname> */ struct completion s_kobj_unregister; }; diff --git a/fs/erofs/sysfs.c b/fs/erofs/sysfs.c index dac252bc9228..2b48a4df19b4 100644 --- a/fs/erofs/sysfs.c +++ b/fs/erofs/sysfs.c @@ -209,6 +209,7 @@ int erofs_register_sysfs(struct super_block *sb) "%s", sb->s_id); if (err) goto put_sb_kobj; + sbi->s_sysfs_inited = true; return 0; put_sb_kobj: @@ -221,9 +222,11 @@ 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_sysfs_inited) { + kobject_del(&sbi->s_kobj); + kobject_put(&sbi->s_kobj); + wait_for_completion(&sbi->s_kobj_unregister); + } } int __init erofs_init_sysfs(void) -- 2.25.1
