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| author | Ivan Pravdin <ipravdin.official@gmail.com> | 2025-07-07 22:06:40 -0400 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-07-19 19:08:27 -0700 |
| commit | 08eabe4b9e98d940d2dd6cdb70c7a9187ca54aca (patch) | |
| tree | 56c37e4d7efdcf219a8629a6652eca27ff906744 /fs/ocfs2 | |
| parent | squashfs: fix incorrect argument to sizeof in kmalloc_array call (diff) | |
| download | linux-08eabe4b9e98d940d2dd6cdb70c7a9187ca54aca.tar.gz linux-08eabe4b9e98d940d2dd6cdb70c7a9187ca54aca.zip | |
ocfs2: avoid potential ABBA deadlock by reordering tl_inode lock
In ocfs2_move_extent(), tl_inode is currently locked after the global
bitmap inode. However, in ocfs2_flush_truncate_log(), the lock order is
reversed: tl_inode is locked first, followed by the global bitmap inode.
This creates a classic ABBA deadlock scenario if two threads attempt these
operations concurrently and acquire the locks in different orders.
To prevent this, move the tl_inode locking earlier in ocfs2_move_extent(),
so that it always precedes the global bitmap inode lock.
No functional changes beyond lock ordering.
Link: https://lkml.kernel.org/r/20250708020640.387741-1-ipravdin.official@gmail.com
Reported-by: syzbot+6bf948e47f9bac7aacfa@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67d5645c.050a0220.1dc86f.0004.GAE@google.com/
Signed-off-by: Ivan Pravdin <ipravdin.official@gmail.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/ocfs2')
| -rw-r--r-- | fs/ocfs2/move_extents.c | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/fs/ocfs2/move_extents.c b/fs/ocfs2/move_extents.c index 369c7d27befd..cbe2f8ed8897 100644 --- a/fs/ocfs2/move_extents.c +++ b/fs/ocfs2/move_extents.c @@ -617,6 +617,8 @@ static int ocfs2_move_extent(struct ocfs2_move_extents_context *context, */ credits += OCFS2_INODE_UPDATE_CREDITS + 1; + inode_lock(tl_inode); + /* * ocfs2_move_extent() didn't reserve any clusters in lock_allocators() * logic, while we still need to lock the global_bitmap. @@ -626,7 +628,7 @@ static int ocfs2_move_extent(struct ocfs2_move_extents_context *context, if (!gb_inode) { mlog(ML_ERROR, "unable to get global_bitmap inode\n"); ret = -EIO; - goto out; + goto out_unlock_tl_inode; } inode_lock(gb_inode); @@ -634,16 +636,14 @@ static int ocfs2_move_extent(struct ocfs2_move_extents_context *context, ret = ocfs2_inode_lock(gb_inode, &gb_bh, 1); if (ret) { mlog_errno(ret); - goto out_unlock_gb_mutex; + goto out_unlock_gb_inode; } - inode_lock(tl_inode); - handle = ocfs2_start_trans(osb, credits); if (IS_ERR(handle)) { ret = PTR_ERR(handle); mlog_errno(ret); - goto out_unlock_tl_inode; + goto out_unlock; } new_phys_blkno = ocfs2_clusters_to_blocks(inode->i_sb, *new_phys_cpos); @@ -703,15 +703,14 @@ static int ocfs2_move_extent(struct ocfs2_move_extents_context *context, out_commit: ocfs2_commit_trans(osb, handle); brelse(gd_bh); - -out_unlock_tl_inode: - inode_unlock(tl_inode); - +out_unlock: ocfs2_inode_unlock(gb_inode, 1); -out_unlock_gb_mutex: +out_unlock_gb_inode: inode_unlock(gb_inode); brelse(gb_bh); iput(gb_inode); +out_unlock_tl_inode: + inode_unlock(tl_inode); out: if (context->meta_ac) { |