The patch titled
Subject: nilfs2: prevent kernel bug at submit_bh_wbc()
has been added to the -mm mm-nonmm-unstable branch. Its filename is
nilfs2-prevent-kernel-bug-at-submit_bh_wbc.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/nilfs2-prevent-kernel-bug-at-submit_bh_wbc.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Subject: nilfs2: prevent kernel bug at submit_bh_wbc()
Date: Wed, 13 Mar 2024 19:58:27 +0900
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.
Link: https://lkml.kernel.org/r/20240313105827.5296-3-konishi.ryusuke@xxxxxxxxx
Fixes: 1f5abe7e7dbc ("nilfs2: replace BUG_ON and BUG calls triggerable from ioctl")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/nilfs2/inode.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/nilfs2/inode.c~nilfs2-prevent-kernel-bug-at-submit_bh_wbc
+++ a/fs/nilfs2/inode.c
@@ -112,7 +112,7 @@ int nilfs_get_block(struct inode *inode,
"%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;
_
Patches currently in -mm which might be from konishi.ryusuke@xxxxxxxxx are
nilfs2-fix-failure-to-detect-dat-corruption-in-btree-and-direct-mappings.patch
nilfs2-prevent-kernel-bug-at-submit_bh_wbc.patch
