====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ kworker/u8:4/30961 is trying to acquire lock: ffff8880384c80c8 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline] ffff8880384c80c8 (&ei->xattr_sem){++++}-{4:4}, at: ext4_destroy_inline_data+0x2d/0xe0 fs/ext4/inline.c:1797 but task is already holding lock: ffff88802884ab98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x278/0x600 mm/page-writeback.c:2554 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 include/linux/percpu-rwsem.h:53 [inline] percpu_down_read include/linux/percpu-rwsem.h:77 [inline] ext4_writepages_down_read fs/ext4/ext4.h:1813 [inline] ext4_writepages+0x21d/0x790 fs/ext4/inode.c:3018 do_writepages+0x278/0x600 mm/page-writeback.c:2554 __writeback_single_inode+0x164/0x13c0 fs/fs-writeback.c:1750 writeback_single_inode+0x4d3/0xf30 fs/fs-writeback.c:1869 write_inode_now+0x174/0x1f0 fs/fs-writeback.c:2954 iput_final fs/inode.c:1956 [inline] iput.part.0+0x7f3/0xf50 fs/inode.c:2015 iput+0x35/0x40 fs/inode.c:1981 ext4_xattr_block_set+0x6f7/0x3660 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+0x17c6/0x1d70 fs/ext4/xattr.c:2832 __ext4_expand_extra_isize+0x346/0x480 fs/ext4/inode.c:6297 ext4_try_to_expand_extra_isize fs/ext4/inode.c:6340 [inline] __ext4_mark_inode_dirty+0x693/0x8b0 fs/ext4/inode.c:6418 ext4_evict_inode+0x860/0x17c0 fs/ext4/inode.c:255 evict+0x3c2/0xad0 fs/inode.c:846 iput_final fs/inode.c:1966 [inline] iput.part.0+0x605/0xf50 fs/inode.c:2015 iput+0x35/0x40 fs/inode.c:1981 ext4_orphan_cleanup+0x71e/0x11e0 fs/ext4/orphan.c:472 __ext4_fill_super fs/ext4/super.c:5670 [inline] ext4_fill_super+0x9009/0xb470 fs/ext4/super.c:5793 get_tree_bdev_flags+0x38c/0x620 fs/super.c:1694 vfs_get_tree+0x92/0x320 fs/super.c:1754 fc_mount fs/namespace.c:1193 [inline] do_new_mount_fc fs/namespace.c:3760 [inline] do_new_mount fs/namespace.c:3836 [inline] path_mount+0x7d0/0x23d0 fs/namespace.c:4146 do_mount fs/namespace.c:4159 [inline] __do_sys_mount fs/namespace.c:4348 [inline] __se_sys_mount fs/namespace.c:4325 [inline] __x64_sys_mount+0x293/0x310 fs/namespace.c:4325 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 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+0x14b8/0x2630 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1cf/0x380 kernel/locking/lockdep.c:5825 down_write+0x8b/0x1f0 kernel/locking/rwsem.c:1590 ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline] ext4_destroy_inline_data+0x2d/0xe0 fs/ext4/inline.c:1797 ext4_do_writepages+0x1185/0x3f50 fs/ext4/inode.c:2804 ext4_writepages+0x347/0x790 fs/ext4/inode.c:3019 do_writepages+0x278/0x600 mm/page-writeback.c:2554 __writeback_single_inode+0x164/0x13c0 fs/fs-writeback.c:1750 writeback_sb_inodes+0x72e/0x1bf0 fs/fs-writeback.c:2041 wb_writeback+0x1c0/0xbe0 fs/fs-writeback.c:2227 wb_do_writeback fs/fs-writeback.c:2374 [inline] wb_workfn+0x142/0xc00 fs/fs-writeback.c:2414 process_one_work+0x9d7/0x1920 kernel/workqueue.c:3275 process_scheduled_works kernel/workqueue.c:3358 [inline] worker_thread+0x5da/0xe40 kernel/workqueue.c:3439 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x754/0xd80 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/u8:4/30961: #0: ffff888020ac8948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x1287/0x1920 kernel/workqueue.c:3250 #1: ffffc90005e37d08 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x93c/0x1920 kernel/workqueue.c:3251 #2: ffff88802884ab98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x278/0x600 mm/page-writeback.c:2554 stack backtrace: CPU: 0 UID: 0 PID: 30961 Comm: kworker/u8:4 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Workqueue: writeback wb_workfn (flush-7:5) Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043 check_noncircular+0x146/0x160 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+0x14b8/0x2630 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1cf/0x380 kernel/locking/lockdep.c:5825 down_write+0x8b/0x1f0 kernel/locking/rwsem.c:1590 ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline] ext4_destroy_inline_data+0x2d/0xe0 fs/ext4/inline.c:1797 ext4_do_writepages+0x1185/0x3f50 fs/ext4/inode.c:2804 ext4_writepages+0x347/0x790 fs/ext4/inode.c:3019 do_writepages+0x278/0x600 mm/page-writeback.c:2554 __writeback_single_inode+0x164/0x13c0 fs/fs-writeback.c:1750 writeback_sb_inodes+0x72e/0x1bf0 fs/fs-writeback.c:2041 wb_writeback+0x1c0/0xbe0 fs/fs-writeback.c:2227 wb_do_writeback fs/fs-writeback.c:2374 [inline] wb_workfn+0x142/0xc00 fs/fs-writeback.c:2414 process_one_work+0x9d7/0x1920 kernel/workqueue.c:3275 process_scheduled_works kernel/workqueue.c:3358 [inline] worker_thread+0x5da/0xe40 kernel/workqueue.c:3439 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x754/0xd80 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:1312: 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 200 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=208 EXT4-fs (loop5): Block reservation details EXT4-fs (loop5): i_reserved_data_blocks=13