Re: [syzbot] general protection fault in bch2_fs_recovery

syzbot
2024-09-10T20:32:42Z

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: general protection fault in bch2_fs_recovery
Author: djahchankoike@gmail.com

#syz test

When a sb is marked clean but doesn't have a clean section
bch2_read_superblock_clean returns NULL which PTR_ERR_OR_ZERO
lets through (returns 0), eventually leading to a null ptr
dereference down the line. Adjust read sb clean to return an
ERR_PTR indicating the invalid clean section.

Signed-off-by: Diogo Jahchan Koike <djahchankoike@gmail.com>
---
fs/bcachefs/sb-clean.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/bcachefs/sb-clean.c b/fs/bcachefs/sb-clean.c
index c57d42bb8d1b..025848a9c4c0 100644
--- a/fs/bcachefs/sb-clean.c
+++ b/fs/bcachefs/sb-clean.c
@@ -155,7 +155,7 @@ struct bch_sb_field_clean *bch2_read_superblock_clean(struct bch_fs *c)
SET_BCH_SB_CLEAN(c->disk_sb.sb, false);
c->sb.clean = false;
mutex_unlock(&c->sb_lock);
- return NULL;
+ return ERR_PTR(-BCH_ERR_invalid_sb_clean);
}

clean = kmemdup(sb_clean, vstruct_bytes(&sb_clean->field),
--
2.43.0