====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kworker/u4:8/2965 is trying to acquire lock: ffff888020972990 (jbd2_handle){++++}-{0:0}, at: wait_transaction_locked+0x1aa/0x270 fs/jbd2/transaction.c:155 but task is already holding lock: ffff888020970bd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1767 [inline] ffff888020970bd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1a4/0x350 fs/ext4/inode.c:2806 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&sbi->s_writepages_rwsem ){++++}-{0:0}: percpu_down_read+0x44/0x1a0 include/linux/percpu-rwsem.h:51 ext4_writepages_down_read fs/ext4/ext4.h:1767 [inline] ext4_writepages+0x1a4/0x350 fs/ext4/inode.c:2806 do_writepages+0x3b3/0x630 mm/page-writeback.c:2575 __writeback_single_inode+0x153/0xec0 fs/fs-writeback.c:1635 writeback_single_inode+0x21f/0x760 fs/fs-writeback.c:1756 write_inode_now+0x183/0x210 fs/fs-writeback.c:2802 iput_final fs/inode.c:1807 [inline] iput+0x5ae/0x920 fs/inode.c:1846 ext4_xattr_block_set+0x273f/0x32b0 fs/ext4/xattr.c:2198 ext4_xattr_move_to_block fs/ext4/xattr.c:2663 [inline] ext4_xattr_make_inode_space fs/ext4/xattr.c:2738 [inline] ext4_expand_extra_isize_ea+0x12c5/0x1e80 fs/ext4/xattr.c:2826 __ext4_expand_extra_isize+0x306/0x400 fs/ext4/inode.c:5971 ext4_try_to_expand_extra_isize fs/ext4/inode.c:6014 [inline] __ext4_mark_inode_dirty+0x45d/0x6e0 fs/ext4/inode.c:6092 ext4_evict_inode+0x7f3/0xea0 fs/ext4/inode.c:252 evict+0x4ca/0x8d0 fs/inode.c:705 ext4_orphan_cleanup+0xbec/0x1420 fs/ext4/orphan.c:472 __ext4_fill_super fs/ext4/super.c:5617 [inline] ext4_fill_super+0x5ed3/0x6790 fs/ext4/super.c:5740 get_tree_bdev+0x3f3/0x520 fs/super.c:1591 vfs_get_tree+0x8c/0x280 fs/super.c:1764 do_new_mount+0x24b/0xa40 fs/namespace.c:3386 do_mount fs/namespace.c:3726 [inline] __do_sys_mount fs/namespace.c:3935 [inline] __se_sys_mount+0x2e7/0x3d0 fs/namespace.c:3912 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #1 (&ei->xattr_sem){++++}-{3:3}: down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520 ext4_setattr+0x86b/0x1ca0 fs/ext4/inode.c:5494 notify_change+0xb0d/0xe10 fs/attr.c:499 chown_common+0x413/0x5d0 fs/open.c:783 do_fchownat+0x14b/0x240 fs/open.c:814 __do_sys_chown fs/open.c:834 [inline] __se_sys_chown fs/open.c:832 [inline] __x64_sys_chown+0x82/0x90 fs/open.c:832 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (jbd2_handle){++++}-{0:0}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2df1/0x7d40 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 wait_transaction_locked+0x1c3/0x270 fs/jbd2/transaction.c:155 add_transaction_credits fs/jbd2/transaction.c:226 [inline] start_this_handle+0x7e8/0x21c0 fs/jbd2/transaction.c:407 jbd2__journal_start+0x2bb/0x5b0 fs/jbd2/transaction.c:505 __ext4_journal_start_sb+0x203/0x560 fs/ext4/ext4_jbd2.c:112 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline] ext4_do_writepages+0xfb7/0x3990 fs/ext4/inode.c:2701 ext4_writepages+0x1dd/0x350 fs/ext4/inode.c:2807 do_writepages+0x3b3/0x630 mm/page-writeback.c:2575 __writeback_single_inode+0x153/0xec0 fs/fs-writeback.c:1635 writeback_sb_inodes+0x7cd/0xf50 fs/fs-writeback.c:1926 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:1997 wb_writeback+0x47e/0xbf0 fs/fs-writeback.c:2107 wb_check_old_data_flush fs/fs-writeback.c:2211 [inline] wb_do_writeback fs/fs-writeback.c:2264 [inline] wb_workfn+0xad7/0xe60 fs/fs-writeback.c:2292 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 other info that might help us debug this: Chain exists of: jbd2_handle --> &ei->xattr_sem --> &sbi->s_writepages_rwsem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(&sbi->s_writepages_rwsem); lock(&ei->xattr_sem); lock(&sbi->s_writepages_rwsem); lock(jbd2_handle); *** DEADLOCK *** 4 locks held by kworker/u4:8/2965: #0: ffff888142a40538 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff888142a40538 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711 #1: ffffc9000c24fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc9000c24fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711 #2: ffff8880208be0e0 (&type->s_umount_key#32){++++}-{3:3}, at: super_trylock_shared+0x20/0xf0 fs/super.c:607 #3: ffff888020970bd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1767 [inline] #3: ffff888020970bd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1a4/0x350 fs/ext4/inode.c:2806 stack backtrace: CPU: 1 PID: 2965 Comm: kworker/u4:8 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: writeback wb_workfn (flush-8:0) Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 check_noncircular+0x2fc/0x400 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2df1/0x7d40 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 wait_transaction_locked+0x1c3/0x270 fs/jbd2/transaction.c:155 add_transaction_credits fs/jbd2/transaction.c:226 [inline] start_this_handle+0x7e8/0x21c0 fs/jbd2/transaction.c:407 jbd2__journal_start+0x2bb/0x5b0 fs/jbd2/transaction.c:505 __ext4_journal_start_sb+0x203/0x560 fs/ext4/ext4_jbd2.c:112 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline] ext4_do_writepages+0xfb7/0x3990 fs/ext4/inode.c:2701 ext4_writepages+0x1dd/0x350 fs/ext4/inode.c:2807 do_writepages+0x3b3/0x630 mm/page-writeback.c:2575 __writeback_single_inode+0x153/0xec0 fs/fs-writeback.c:1635 writeback_sb_inodes+0x7cd/0xf50 fs/fs-writeback.c:1926 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:1997 wb_writeback+0x47e/0xbf0 fs/fs-writeback.c:2107 wb_check_old_data_flush fs/fs-writeback.c:2211 [inline] wb_do_writeback fs/fs-writeback.c:2264 [inline] wb_workfn+0xad7/0xe60 fs/fs-writeback.c:2292 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293