====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kworker/u4:4/526 is trying to acquire lock: ffff0000e21332f0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:158 [inline] ffff0000e21332f0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_destroy_inline_data+0x30/0x114 fs/ext4/inline.c:1922 but task is already holding lock: ffff0000fa1c8b98 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x1b8/0x28b4 fs/ext4/inode.c:2715 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+0x70/0x2a8 include/linux/percpu-rwsem.h:51 ext4_writepages+0x1b8/0x28b4 fs/ext4/inode.c:2715 do_writepages+0x2b0/0x504 mm/page-writeback.c:2491 __writeback_single_inode+0x164/0x1554 fs/fs-writeback.c:1622 writeback_single_inode+0x1cc/0x740 fs/fs-writeback.c:1743 write_inode_now+0x150/0x1cc fs/fs-writeback.c:2780 iput_final fs/inode.c:1821 [inline] iput+0x5bc/0x7e4 fs/inode.c:1860 ext4_xattr_block_set+0x1454/0x2880 fs/ext4/xattr.c:2145 ext4_xattr_move_to_block fs/ext4/xattr.c:2610 [inline] ext4_xattr_make_inode_space fs/ext4/xattr.c:2685 [inline] ext4_expand_extra_isize_ea+0xe5c/0x17ac fs/ext4/xattr.c:2773 __ext4_expand_extra_isize+0x298/0x358 fs/ext4/inode.c:5984 ext4_try_to_expand_extra_isize fs/ext4/inode.c:6027 [inline] __ext4_mark_inode_dirty+0x3e4/0x784 fs/ext4/inode.c:6105 ext4_evict_inode+0xb64/0x1278 fs/ext4/inode.c:279 evict+0x3e0/0x828 fs/inode.c:705 iput_final fs/inode.c:1834 [inline] iput+0x754/0x7e4 fs/inode.c:1860 ext4_process_orphan+0x240/0x2b4 fs/ext4/orphan.c:358 ext4_orphan_cleanup+0x920/0x1060 fs/ext4/orphan.c:472 __ext4_fill_super fs/ext4/super.c:5556 [inline] ext4_fill_super+0x6188/0x660c fs/ext4/super.c:5687 get_tree_bdev+0x358/0x544 fs/super.c:1366 ext4_get_tree+0x28/0x38 fs/ext4/super.c:5717 vfs_get_tree+0x90/0x274 fs/super.c:1573 do_new_mount+0x228/0x810 fs/namespace.c:3078 path_mount+0x5bc/0xe80 fs/namespace.c:3408 do_mount fs/namespace.c:3421 [inline] __do_sys_mount fs/namespace.c:3629 [inline] __se_sys_mount fs/namespace.c:3606 [inline] __arm64_sys_mount+0x49c/0x59c fs/namespace.c:3606 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 -> #0 (&ei->xattr_sem){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2880/0x6800 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662 down_write+0x5c/0x88 kernel/locking/rwsem.c:1573 ext4_write_lock_xattr fs/ext4/xattr.h:158 [inline] ext4_destroy_inline_data+0x30/0x114 fs/ext4/inline.c:1922 ext4_writepages+0x430/0x28b4 fs/ext4/inode.c:2761 do_writepages+0x2b0/0x504 mm/page-writeback.c:2491 __writeback_single_inode+0x164/0x1554 fs/fs-writeback.c:1622 writeback_sb_inodes+0x858/0x143c fs/fs-writeback.c:1913 wb_writeback+0x414/0xfcc fs/fs-writeback.c:2087 wb_do_writeback fs/fs-writeback.c:2230 [inline] wb_workfn+0x360/0xe18 fs/fs-writeback.c:2270 process_one_work+0x7f8/0x13a4 kernel/workqueue.c:2292 worker_thread+0x8c4/0xfec kernel/workqueue.c:2439 kthread+0x250/0x2d8 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 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/u4:4/526: #0: ffff0000c2c10938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x6b8/0x13a4 kernel/workqueue.c:2265 #1: ffff8000211b7c20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x6fc/0x13a4 kernel/workqueue.c:2267 #2: ffff0000fa1c8b98 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x1b8/0x28b4 fs/ext4/inode.c:2715 stack backtrace: CPU: 1 PID: 526 Comm: kworker/u4:4 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025 Workqueue: writeback wb_workfn (flush-7:0) Call trace: dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 print_circular_bug+0x148/0x1b0 kernel/locking/lockdep.c:2048 check_noncircular+0x264/0x2f8 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2880/0x6800 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662 down_write+0x5c/0x88 kernel/locking/rwsem.c:1573 ext4_write_lock_xattr fs/ext4/xattr.h:158 [inline] ext4_destroy_inline_data+0x30/0x114 fs/ext4/inline.c:1922 ext4_writepages+0x430/0x28b4 fs/ext4/inode.c:2761 do_writepages+0x2b0/0x504 mm/page-writeback.c:2491 __writeback_single_inode+0x164/0x1554 fs/fs-writeback.c:1622 writeback_sb_inodes+0x858/0x143c fs/fs-writeback.c:1913 wb_writeback+0x414/0xfcc fs/fs-writeback.c:2087 wb_do_writeback fs/fs-writeback.c:2230 [inline] wb_workfn+0x360/0xe18 fs/fs-writeback.c:2270 process_one_work+0x7f8/0x13a4 kernel/workqueue.c:2292 worker_thread+0x8c4/0xfec kernel/workqueue.c:2439 kthread+0x250/0x2d8 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 EXT4-fs error (device loop0): ext4_mb_generate_buddy:1113: group 0, block bitmap and bg descriptor inconsistent: 0 vs 150994969 free clusters EXT4-fs (loop0): Delayed block allocation failed for inode 15 at logical offset 0 with max blocks 16 with error 28 EXT4-fs (loop0): This should not happen!! Data will be lost EXT4-fs (loop0): Total free blocks count 0 EXT4-fs (loop0): Free/Dirty block details EXT4-fs (loop0): free_blocks=2415919504 EXT4-fs (loop0): dirty_blocks=16 EXT4-fs (loop0): Block reservation details EXT4-fs (loop0): i_reserved_data_blocks=1