====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ kworker/u8:11/9624 is trying to acquire lock: ffff888026f21408 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline] ffff888026f21408 (&ei->xattr_sem){++++}-{4:4}, at: ext4_destroy_inline_data+0x28/0xe0 fs/ext4/inline.c:1797 but task is already holding lock: ffff888053902b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: percpu_down_read include/linux/percpu-rwsem.h:77 [inline] ffff888053902b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1817 [inline] ffff888053902b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x205/0x3b0 fs/ext4/inode.c:3018 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_internal+0x48/0x1c0 include/linux/percpu-rwsem.h:53 percpu_down_read include/linux/percpu-rwsem.h:77 [inline] ext4_writepages_down_read fs/ext4/ext4.h:1817 [inline] ext4_writepages+0x205/0x3b0 fs/ext4/inode.c:3018 do_writepages+0x32e/0x550 mm/page-writeback.c:2554 __writeback_single_inode+0x133/0x1060 fs/fs-writeback.c:1750 writeback_single_inode+0x493/0xc70 fs/fs-writeback.c:1869 write_inode_now+0x1c2/0x290 fs/fs-writeback.c:2954 iput_final fs/inode.c:1947 [inline] iput+0x8c1/0xe80 fs/inode.c:2006 ext4_xattr_block_set+0x1fd4/0x2ad0 fs/ext4/xattr.c:2204 ext4_xattr_move_to_block fs/ext4/xattr.c:2669 [inline] ext4_xattr_make_inode_space fs/ext4/xattr.c:2744 [inline] ext4_expand_extra_isize_ea+0x12cf/0x1ea0 fs/ext4/xattr.c:2832 __ext4_expand_extra_isize+0x30d/0x400 fs/ext4/inode.c:6328 ext4_try_to_expand_extra_isize fs/ext4/inode.c:6371 [inline] __ext4_mark_inode_dirty+0x45c/0x6e0 fs/ext4/inode.c:6449 ext4_evict_inode+0x7a1/0xe60 fs/ext4/inode.c:255 evict+0x61e/0xb10 fs/inode.c:837 ext4_orphan_cleanup+0xc38/0x1470 fs/ext4/orphan.c:472 __ext4_fill_super fs/ext4/super.c:5674 [inline] ext4_fill_super+0x59ff/0x6320 fs/ext4/super.c:5797 get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694 vfs_get_tree+0x92/0x2a0 fs/super.c:1754 fc_mount fs/namespace.c:1193 [inline] do_new_mount_fc fs/namespace.c:3760 [inline] do_new_mount+0x341/0xd30 fs/namespace.c:3836 do_mount fs/namespace.c:4159 [inline] __do_sys_mount fs/namespace.c:4348 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4325 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&ei->xattr_sem){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868 down_write+0x96/0x200 kernel/locking/rwsem.c:1590 ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline] ext4_destroy_inline_data+0x28/0xe0 fs/ext4/inline.c:1797 ext4_do_writepages+0x51e/0x4600 fs/ext4/inode.c:2804 ext4_writepages+0x241/0x3b0 fs/ext4/inode.c:3019 do_writepages+0x32e/0x550 mm/page-writeback.c:2554 __writeback_single_inode+0x133/0x1060 fs/fs-writeback.c:1750 writeback_sb_inodes+0x92c/0x1820 fs/fs-writeback.c:2041 wb_writeback+0x445/0xad0 fs/fs-writeback.c:2227 wb_do_writeback fs/fs-writeback.c:2374 [inline] wb_workfn+0x3f8/0xef0 fs/fs-writeback.c:2414 process_one_work+0x949/0x15a0 kernel/workqueue.c:3279 process_scheduled_works kernel/workqueue.c:3362 [inline] worker_thread+0x9af/0xee0 kernel/workqueue.c:3443 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(&sbi->s_writepages_rwsem); lock(&ei->xattr_sem); lock(&sbi->s_writepages_rwsem); lock(&ei->xattr_sem); *** DEADLOCK *** 3 locks held by kworker/u8:11/9624: #0: ffff88801c6ad148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x855/0x15a0 kernel/workqueue.c:3254 #1: ffffc90010d8fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x87c/0x15a0 kernel/workqueue.c:3255 #2: ffff888053902b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: percpu_down_read include/linux/percpu-rwsem.h:77 [inline] #2: ffff888053902b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1817 [inline] #2: ffff888053902b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x205/0x3b0 fs/ext4/inode.c:3018 stack backtrace: CPU: 1 UID: 0 PID: 9624 Comm: kworker/u8:11 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 Workqueue: writeback wb_workfn (flush-7:5) Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868 down_write+0x96/0x200 kernel/locking/rwsem.c:1590 ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline] ext4_destroy_inline_data+0x28/0xe0 fs/ext4/inline.c:1797 ext4_do_writepages+0x51e/0x4600 fs/ext4/inode.c:2804 ext4_writepages+0x241/0x3b0 fs/ext4/inode.c:3019 do_writepages+0x32e/0x550 mm/page-writeback.c:2554 __writeback_single_inode+0x133/0x1060 fs/fs-writeback.c:1750 writeback_sb_inodes+0x92c/0x1820 fs/fs-writeback.c:2041 wb_writeback+0x445/0xad0 fs/fs-writeback.c:2227 wb_do_writeback fs/fs-writeback.c:2374 [inline] wb_workfn+0x3f8/0xef0 fs/fs-writeback.c:2414 process_one_work+0x949/0x15a0 kernel/workqueue.c:3279 process_scheduled_works kernel/workqueue.c:3362 [inline] worker_thread+0x9af/0xee0 kernel/workqueue.c:3443 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 EXT4-fs error (device loop5): ext4_mb_generate_buddy:1315: group 0, block bitmap and bg descriptor inconsistent: 25 vs 4128793 free clusters EXT4-fs (loop5): Delayed block allocation failed for inode 15 at logical offset 0 with max blocks 1 with error 28 EXT4-fs (loop5): This should not happen!! Data will be lost EXT4-fs (loop5): Total free blocks count 0 EXT4-fs (loop5): Free/Dirty block details EXT4-fs (loop5): free_blocks=66060288 EXT4-fs (loop5): dirty_blocks=3344 EXT4-fs (loop5): Block reservation details EXT4-fs (loop5): i_reserved_data_blocks=209