From: Aleksandr Nogikh Date: Fri, 12 Jun 2026 11:50:20 +0000 (+0000) Subject: ocfs2: fix circular locking dependency in ocfs2_dio_end_io_write X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ff6f26c58421614b02694ac9d219ac61d924bc68;p=thirdparty%2Flinux.git ocfs2: fix circular locking dependency in ocfs2_dio_end_io_write A circular locking dependency involves INODE_ALLOC_SYSTEM_INODE, EXTENT_ALLOC_SYSTEM_INODE, and ORPHAN_DIR_SYSTEM_INODE. 1. ocfs2_mknod() acquires INODE_ALLOC then EXTENT_ALLOC. 2. ocfs2_dio_end_io_write() acquires EXTENT_ALLOC for unwritten extents, then ORPHAN_DIR via ocfs2_del_inode_from_orphan() while still holding EXTENT_ALLOC. 3. ocfs2_wipe_inode() acquires ORPHAN_DIR then INODE_ALLOC via ocfs2_remove_inode. Break the cycle in ocfs2_dio_end_io_write() by freeing the allocation contexts (releasing EXTENT_ALLOC) before acquiring ORPHAN_DIR. WARNING: possible circular locking dependency detected ------------------------------------------------------ is trying to acquire lock: ffff8881e78b33a0 (&ocfs2_sysfile_lock_key[INODE_ALLOC_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_evict_inode+0x1539/0x43b0 fs/ocfs2/inode.c:1299 but task is already holding lock: ffff8881e78b4fa0 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_evict_inode+0xe97/0x43b0 fs/ocfs2/inode.c:1299 the existing dependency chain (in reverse order) is: -> #2 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}: inode_lock include/linux/fs.h:1029 [inline] ocfs2_del_inode_from_orphan+0x12e/0x7a0 fs/ocfs2/namei.c:2728 ocfs2_dio_end_io+0xf9c/0x1370 fs/ocfs2/aops.c:2418 dio_complete+0x25b/0x790 fs/direct-io.c:281 -> #1 (&ocfs2_sysfile_lock_key[EXTENT_ALLOC_SYSTEM_INODE]){+.+.}-{4:4}: inode_lock include/linux/fs.h:1029 [inline] ocfs2_reserve_suballoc_bits+0x16d/0x4840 fs/ocfs2/suballoc.c:882 ocfs2_reserve_new_metadata_blocks+0x415/0x9a0 fs/ocfs2/suballoc.c:1078 ocfs2_mknod+0x10f3/0x2260 fs/ocfs2/namei.c:351 -> #0 (&ocfs2_sysfile_lock_key[INODE_ALLOC_SYSTEM_INODE]){+.+.}-{4:4}: __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 down_write+0x96/0x200 kernel/locking/rwsem.c:1625 inode_lock include/linux/fs.h:1029 [inline] ocfs2_remove_inode fs/ocfs2/inode.c:733 [inline] ocfs2_wipe_inode fs/ocfs2/inode.c:896 [inline] ocfs2_delete_inode fs/ocfs2/inode.c:1157 [inline] ocfs2_evict_inode+0x1539/0x43b0 fs/ocfs2/inode.c:1299 Chain exists of: &ocfs2_sysfile_lock_key[INODE_ALLOC_SYSTEM_INODE] --> &ocfs2_sysfile_lock_key[EXTENT_ALLOC_SYSTEM_INODE] --> &ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE] Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]); lock(&ocfs2_sysfile_lock_key[EXTENT_ALLOC_SYSTEM_INODE]); lock(&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]); lock(&ocfs2_sysfile_lock_key[INODE_ALLOC_SYSTEM_INODE]); *** DEADLOCK *** Link: https://lore.kernel.org/97c902a6-3bcf-43ea-9b70-f1f136a6c3f2@mail.kernel.org Fixes: d647c5b2fbf8 ("ocfs2: split transactions in dio completion to avoid credit exhaustion") Assisted-by: Gemini:gemini-3.1-pro-preview Gemini:gemini-3-flash-preview syzbot Reported-by: syzbot+b225d4dfce6219600c42@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=b225d4dfce6219600c42 Link: https://syzkaller.appspot.com/ai_job?id=0b53ce1e-2972-4192-aa85-8097a702762c Signed-off-by: Aleksandr Nogikh Reviewed-by: Heming Zhao Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Cc: Joseph Qi Cc: Changwei Ge Cc: Jun Piao Signed-off-by: Andrew Morton --- diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index 6ec198bdab121..4acdbb70882cd 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -2372,6 +2372,15 @@ commit: unlock: up_write(&oi->ip_alloc_sem); + if (data_ac) { + ocfs2_free_alloc_context(data_ac); + data_ac = NULL; + } + if (meta_ac) { + ocfs2_free_alloc_context(meta_ac); + meta_ac = NULL; + } + /* everything looks good, let's start the cleanup */ if (!ret && dwc->dw_orphaned) { BUG_ON(dwc->dw_writer_pid != task_pid_nr(current)); @@ -2383,10 +2392,6 @@ unlock: ocfs2_inode_unlock(inode, 1); brelse(di_bh); out: - if (data_ac) - ocfs2_free_alloc_context(data_ac); - if (meta_ac) - ocfs2_free_alloc_context(meta_ac); ocfs2_run_deallocs(osb, &dealloc); ocfs2_dio_free_write_ctx(inode, dwc);