====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kworker/u4:27/6397 is trying to acquire lock: ffff8880558680c8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:158 [inline] ffff8880558680c8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_destroy_inline_data+0x24/0xe0 fs/ext4/inline.c:1930 but task is already holding lock: ffff88801fa56c18 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x213/0x2e70 fs/ext4/inode.c:2717 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&sbi->s_writepages_rwsem){.+.+}-{0:0}: percpu_down_read+0x44/0x1a0 include/linux/percpu-rwsem.h:51 ext4_writepages+0x213/0x2e70 fs/ext4/inode.c:2717 do_writepages+0x3c6/0x640 mm/page-writeback.c:2491 __writeback_single_inode+0x153/0x1170 fs/fs-writeback.c:1622 writeback_single_inode+0x3d2/0x8e0 fs/fs-writeback.c:1743 write_inode_now+0x17f/0x210 fs/fs-writeback.c:2786 iput_final fs/inode.c:1821 [inline] iput+0x643/0x9c0 fs/inode.c:1860 ext4_xattr_block_set+0x2224/0x2fe0 fs/ext4/xattr.c:2095 ext4_xattr_move_to_block fs/ext4/xattr.c:2613 [inline] ext4_xattr_make_inode_space fs/ext4/xattr.c:2688 [inline] ext4_expand_extra_isize_ea+0xfca/0x1d40 fs/ext4/xattr.c:2776 __ext4_expand_extra_isize+0x301/0x3e0 fs/ext4/inode.c:6003 ext4_try_to_expand_extra_isize fs/ext4/inode.c:6046 [inline] __ext4_mark_inode_dirty+0x478/0x760 fs/ext4/inode.c:6124 ext4_evict_inode+0xa67/0x10e0 fs/ext4/inode.c:281 evict+0x4b6/0x8b0 fs/inode.c:705 ext4_orphan_cleanup+0xc32/0x1470 fs/ext4/orphan.c:472 __ext4_fill_super fs/ext4/super.c:5574 [inline] ext4_fill_super+0x6f0c/0x78f0 fs/ext4/super.c:5693 get_tree_bdev+0x3e6/0x610 fs/super.c:1366 vfs_get_tree+0x88/0x270 fs/super.c:1573 do_new_mount+0x247/0xa40 fs/namespace.c:3078 do_mount fs/namespace.c:3421 [inline] __do_sys_mount fs/namespace.c:3629 [inline] __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3606 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (&ei->xattr_sem){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3830 [inline] __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676 down_write+0x36/0x60 kernel/locking/rwsem.c:1573 ext4_write_lock_xattr fs/ext4/xattr.h:158 [inline] ext4_destroy_inline_data+0x24/0xe0 fs/ext4/inline.c:1930 ext4_writepages+0x599/0x2e70 fs/ext4/inode.c:2763 do_writepages+0x3c6/0x640 mm/page-writeback.c:2491 __writeback_single_inode+0x153/0x1170 fs/fs-writeback.c:1622 writeback_sb_inodes+0xad5/0x17f0 fs/fs-writeback.c:1913 wb_writeback+0x470/0xd40 fs/fs-writeback.c:2087 wb_do_writeback fs/fs-writeback.c:2230 [inline] wb_workfn+0x423/0xee0 fs/fs-writeback.c:2270 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sbi->s_writepages_rwsem); lock(&ei->xattr_sem); lock(&sbi->s_writepages_rwsem); lock(&ei->xattr_sem); *** DEADLOCK *** 3 locks held by kworker/u4:27/6397: #0: ffff88801ba6f938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #1: ffffc90004d9fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #2: ffff88801fa56c18 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x213/0x2e70 fs/ext4/inode.c:2717 stack backtrace: CPU: 1 PID: 6397 Comm: kworker/u4:27 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: writeback wb_workfn (flush-7:4) Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3830 [inline] __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676 down_write+0x36/0x60 kernel/locking/rwsem.c:1573 ext4_write_lock_xattr fs/ext4/xattr.h:158 [inline] ext4_destroy_inline_data+0x24/0xe0 fs/ext4/inline.c:1930 ext4_writepages+0x599/0x2e70 fs/ext4/inode.c:2763 do_writepages+0x3c6/0x640 mm/page-writeback.c:2491 __writeback_single_inode+0x153/0x1170 fs/fs-writeback.c:1622 writeback_sb_inodes+0xad5/0x17f0 fs/fs-writeback.c:1913 wb_writeback+0x470/0xd40 fs/fs-writeback.c:2087 wb_do_writeback fs/fs-writeback.c:2230 [inline] wb_workfn+0x423/0xee0 fs/fs-writeback.c:2270 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 EXT4-fs error (device loop4): ext4_mb_generate_buddy:1126: group 0, block bitmap and bg descriptor inconsistent: 25 vs 281 free clusters EXT4-fs (loop4): Delayed block allocation failed for inode 15 at logical offset 0 with max blocks 1 with error 28 EXT4-fs (loop4): This should not happen!! Data will be lost EXT4-fs (loop4): Total free blocks count 0 EXT4-fs (loop4): Free/Dirty block details EXT4-fs (loop4): free_blocks=4096 EXT4-fs (loop4): dirty_blocks=32 EXT4-fs (loop4): Block reservation details EXT4-fs (loop4): i_reserved_data_blocks=2 EXT4-fs (loop4): Delayed block allocation failed for inode 15 at logical offset 64 with max blocks 32 with error 28