From: Ryusuke Konishi <konishi.ryusuke@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: syzbot <syzbot+cfed5b56649bddf80d6e@syzkaller.appspotmail.com>,
syzkaller-bugs@googlegroups.com, linux-nilfs@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] nilfs2: prevent kernel bug at submit_bh_wbc()
Date: Wed, 13 Mar 2024 19:58:27 +0900 [thread overview]
Message-ID: <20240313105827.5296-3-konishi.ryusuke@gmail.com> (raw)
In-Reply-To: <20240313105827.5296-1-konishi.ryusuke@gmail.com>
Fix a bug where nilfs_get_block() returns a successful status when
searching and inserting the specified block both fail inconsistently.
If this inconsistent behavior is not due to a previously fixed bug,
then an unexpected race is occurring, so return a temporary error
-EAGAIN instead.
This prevents callers such as __block_write_begin_int() from
requesting a read into a buffer that is not mapped, which would cause
the BUG_ON check for the BH_Mapped flag in submit_bh_wbc() to fail.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Fixes: 1f5abe7e7dbc ("nilfs2: replace BUG_ON and BUG calls triggerable from ioctl")
Cc: stable@vger.kernel.org
---
fs/nilfs2/inode.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index 9c334c722fc1..5a888b2c1803 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -112,7 +112,7 @@ int nilfs_get_block(struct inode *inode, sector_t blkoff,
"%s (ino=%lu): a race condition while inserting a data block at offset=%llu",
__func__, inode->i_ino,
(unsigned long long)blkoff);
- err = 0;
+ err = -EAGAIN;
}
nilfs_transaction_abort(inode->i_sb);
goto out;
--
2.34.1
prev parent reply other threads:[~2024-03-13 10:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <0000000000002df264056a35b16b@google.com>
2024-03-13 10:58 ` [PATCH 0/2] nilfs2: fix kernel bug at submit_bh_wbc() Ryusuke Konishi
2024-03-13 10:58 ` [PATCH 1/2] nilfs2: fix failure to detect DAT corruption in btree and direct mappings Ryusuke Konishi
2024-03-13 10:58 ` Ryusuke Konishi [this message]
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