====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kworker/u4:10/4432 is trying to acquire lock: ffff888048924700 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline] ffff888048924700 (&ei->xattr_sem){++++}-{3:3}, at: ext4_destroy_inline_data+0x24/0xe0 fs/ext4/inline.c:1912 but task is already holding lock: ffff88807bdaeb98 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x1c0/0x2e50 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+0x44/0x1a0 include/linux/percpu-rwsem.h:51 ext4_writepages+0x1c0/0x2e50 fs/ext4/inode.c:2715 do_writepages+0x3b7/0x610 mm/page-writeback.c:2491 __writeback_single_inode+0x156/0x1160 fs/fs-writeback.c:1622 writeback_single_inode+0x221/0x8b0 fs/fs-writeback.c:1743 write_inode_now+0x15d/0x1d0 fs/fs-writeback.c:2780 iput_final fs/inode.c:1821 [inline] iput+0x613/0x980 fs/inode.c:1860 ext4_xattr_block_set+0x2736/0x32a0 fs/ext4/xattr.c:2158 ext4_xattr_move_to_block fs/ext4/xattr.c:2626 [inline] ext4_xattr_make_inode_space fs/ext4/xattr.c:2701 [inline] ext4_expand_extra_isize_ea+0x109b/0x19b0 fs/ext4/xattr.c:2793 __ext4_expand_extra_isize+0x301/0x3e0 fs/ext4/inode.c:5980 ext4_try_to_expand_extra_isize fs/ext4/inode.c:6023 [inline] __ext4_mark_inode_dirty+0x47f/0x770 fs/ext4/inode.c:6101 ext4_evict_inode+0xa73/0x1100 fs/ext4/inode.c:279 evict+0x485/0x870 fs/inode.c:705 ext4_orphan_cleanup+0xbd3/0x1400 fs/ext4/orphan.c:470 __ext4_fill_super fs/ext4/super.c:5530 [inline] ext4_fill_super+0x7bdf/0x8150 fs/ext4/super.c:5661 get_tree_bdev+0x3f1/0x610 fs/super.c:1366 vfs_get_tree+0x88/0x270 fs/super.c:1573 do_new_mount+0x24a/0xa40 fs/namespace.c:3078 do_mount fs/namespace.c:3421 [inline] __do_sys_mount fs/namespace.c:3629 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3606 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #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+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 down_write+0x36/0x60 kernel/locking/rwsem.c:1573 ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline] ext4_destroy_inline_data+0x24/0xe0 fs/ext4/inline.c:1912 ext4_writepages+0x5df/0x2e50 fs/ext4/inode.c:2761 do_writepages+0x3b7/0x610 mm/page-writeback.c:2491 __writeback_single_inode+0x156/0x1160 fs/fs-writeback.c:1622 writeback_sb_inodes+0xad8/0x17d0 fs/fs-writeback.c:1913 wb_writeback+0x468/0xd00 fs/fs-writeback.c:2087 wb_do_writeback fs/fs-writeback.c:2230 [inline] wb_workfn+0x435/0xec0 fs/fs-writeback.c:2270 process_one_work+0x898/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1250 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/u4:10/4432: #0: ffff88801c65c938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90004c67d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #2: ffff88807bdaeb98 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x1c0/0x2e50 fs/ext4/inode.c:2715 stack backtrace: CPU: 1 PID: 4432 Comm: kworker/u4:10 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: writeback wb_workfn (flush-7:1) Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 check_noncircular+0x274/0x310 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+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 down_write+0x36/0x60 kernel/locking/rwsem.c:1573 ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline] ext4_destroy_inline_data+0x24/0xe0 fs/ext4/inline.c:1912 ext4_writepages+0x5df/0x2e50 fs/ext4/inode.c:2761 do_writepages+0x3b7/0x610 mm/page-writeback.c:2491 __writeback_single_inode+0x156/0x1160 fs/fs-writeback.c:1622 writeback_sb_inodes+0xad8/0x17d0 fs/fs-writeback.c:1913 wb_writeback+0x468/0xd00 fs/fs-writeback.c:2087 wb_do_writeback fs/fs-writeback.c:2230 [inline] wb_workfn+0x435/0xec0 fs/fs-writeback.c:2270 process_one_work+0x898/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1250 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 loop1): ext4_mb_generate_buddy:1097: group 0, block bitmap and bg descriptor inconsistent: 0 vs 150994969 free clusters EXT4-fs (loop1): Delayed block allocation failed for inode 15 at logical offset 0 with max blocks 1 with error 28 EXT4-fs (loop1): This should not happen!! Data will be lost EXT4-fs (loop1): Total free blocks count 0 EXT4-fs (loop1): Free/Dirty block details EXT4-fs (loop1): free_blocks=2415919504 EXT4-fs (loop1): dirty_blocks=32 EXT4-fs (loop1): Block reservation details EXT4-fs (loop1): i_reserved_data_blocks=2