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([2405:201:682f:383f:6622:5068:7fd9:7931]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2c7444a9c4fsm15219195ad.75.2026.06.20.01.08.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 20 Jun 2026 01:08:10 -0700 (PDT) From: Deepanshu Kartikey To: mark@fasheh.com, jlbec@evilplan.org, joseph.qi@linux.alibaba.com, bigeasy@linutronix.de, clrkwllms@kernel.org, rostedt@goodmis.org Cc: ocfs2-devel@lists.linux.dev, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, Deepanshu Kartikey , syzbot+ce129763ce7d7e914739@syzkaller.appspotmail.com Subject: [PATCH] ocfs2: fix deadlock in dio write orphan cleanup path Date: Sat, 20 Jun 2026 13:38:02 +0530 Message-ID: <20260620080802.35165-1-kartikey406@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit PREEMPT_RT's rtmutex PI chain walker detected a lock dependency cycle in a single thread: ocfs2_file_write_iter() inode_lock(file_inode) [Lock A] ocfs2_dio_end_io_write() ocfs2_inode_lock() [Lock B] ocfs2_del_inode_from_orphan() inode_lock(orphan_dir) [Lock D] <- cycle detected! The problem is lock ordering. Lock B is held when Lock D is acquired. Recovery paths acquire these locks in a different order creating a potential cycle in the lock dependency graph. Fix this by releasing Lock B (ocfs2_inode_unlock + brelse(di_bh)) BEFORE calling ocfs2_del_inode_from_orphan(). Pass NULL for di_bh to signal that ocfs2_del_inode_from_orphan() should acquire its own fresh cluster lock and di_bh internally. This ensures consistent lock ordering: Before: B held -> D acquired (inconsistent) After: B released -> B' fresh -> D (consistent) Reported-by: syzbot+ce129763ce7d7e914739@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=ce129763ce7d7e914739 Signed-off-by: Deepanshu Kartikey --- fs/ocfs2/aops.c | 21 +++++++++++++++------ fs/ocfs2/namei.c | 17 ++++++++++++++++- 2 files changed, 31 insertions(+), 7 deletions(-) diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index 6ec198bdab12..15b059a23ebc 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -2280,6 +2280,7 @@ static int ocfs2_dio_end_io_write(struct inode *inode, handle_t *handle = NULL; loff_t end = offset + bytes; int ret = 0, credits = 0, batch = 0; + bool orphaned = false; ocfs2_init_dealloc_ctxt(&dealloc); @@ -2371,17 +2372,25 @@ static int ocfs2_dio_end_io_write(struct inode *inode, ocfs2_commit_trans(osb, handle); unlock: up_write(&oi->ip_alloc_sem); + /* + * Release the cluster lock and di_bh BEFORE calling + * ocfs2_del_inode_from_orphan(). That function will acquire + * inode_lock(orphan_dir_inode) which would cause an AB-BA + * deadlock with recovery paths that hold orphan_dir lock + * before acquiring the file inode lock. + */ + orphaned = (!ret && dwc->dw_orphaned); + ocfs2_inode_unlock(inode, 1); + brelse(di_bh); + di_bh = NULL; - /* everything looks good, let's start the cleanup */ - if (!ret && dwc->dw_orphaned) { + /* everything looks good, let's start the orphan cleanup */ + if (orphaned) { BUG_ON(dwc->dw_writer_pid != task_pid_nr(current)); - - ret = ocfs2_del_inode_from_orphan(osb, inode, di_bh, 0, 0); + ret = ocfs2_del_inode_from_orphan(osb, inode, NULL, 0, 0); if (ret < 0) mlog_errno(ret); } - ocfs2_inode_unlock(inode, 1); - brelse(di_bh); out: if (data_ac) ocfs2_free_alloc_context(data_ac); diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c index 1277666c77cd..25bbe2a9776e 100644 --- a/fs/ocfs2/namei.c +++ b/fs/ocfs2/namei.c @@ -2712,10 +2712,21 @@ int ocfs2_del_inode_from_orphan(struct ocfs2_super *osb, { struct inode *orphan_dir_inode = NULL; struct buffer_head *orphan_dir_bh = NULL; - struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data; + struct ocfs2_dinode *di; handle_t *handle = NULL; int status = 0; + struct buffer_head *local_di_bh = NULL; + if (!di_bh) { + status = ocfs2_inode_lock(inode, &local_di_bh, 1); + if (status < 0) { + mlog_errno(status); + return status; + } + di_bh = local_di_bh; + } + + di = (struct ocfs2_dinode *)di_bh->b_data; orphan_dir_inode = ocfs2_get_system_file_inode(osb, ORPHAN_DIR_SYSTEM_INODE, le16_to_cpu(di->i_dio_orphaned_slot)); @@ -2779,6 +2790,10 @@ int ocfs2_del_inode_from_orphan(struct ocfs2_super *osb, iput(orphan_dir_inode); bail: + if (local_di_bh) { + ocfs2_inode_unlock(inode, 1); + brelse(local_di_bh); + } return status; } -- 2.43.0