====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.4.2754/15839 is trying to acquire lock: ffff888073ae32f0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline] ffff888073ae32f0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_destroy_inline_data+0x24/0xe0 fs/ext4/inline.c:1912 but task is already holding lock: ffff888028256b98 (&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 filemap_fdatawrite_wbc+0x11e/0x180 mm/filemap.c:388 __filemap_fdatawrite_range mm/filemap.c:421 [inline] __filemap_fdatawrite mm/filemap.c:427 [inline] filemap_flush+0xc1/0x110 mm/filemap.c:454 ext4_release_file+0x7e/0x300 fs/ext4/file.c:158 __fput+0x22c/0x920 fs/file_table.c:320 task_work_run+0x1ca/0x250 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 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 *** 1 lock held by syz.4.2754/15839: #0: ffff888028256b98 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x1c0/0x2e50 fs/ext4/inode.c:2715 stack backtrace: CPU: 0 PID: 15839 Comm: syz.4.2754 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 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 filemap_fdatawrite_wbc+0x11e/0x180 mm/filemap.c:388 __filemap_fdatawrite_range mm/filemap.c:421 [inline] __filemap_fdatawrite mm/filemap.c:427 [inline] filemap_flush+0xc1/0x110 mm/filemap.c:454 ext4_release_file+0x7e/0x300 fs/ext4/file.c:158 __fput+0x22c/0x920 fs/file_table.c:320 task_work_run+0x1ca/0x250 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fa9ce38f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc7f35d658 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007fa9ce5e7da0 RCX: 00007fa9ce38f749 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007fa9ce5e7da0 R08: 0000000000000030 R09: 000000037f35d94f R10: 00000000003ffdac R11: 0000000000000246 R12: 00000000000be4cb R13: 00007ffc7f35d750 R14: ffffffffffffffff R15: 00007ffc7f35d770 EXT4-fs error (device loop4): ext4_mb_generate_buddy:1097: 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 690 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=704 EXT4-fs (loop4): Block reservation details EXT4-fs (loop4): i_reserved_data_blocks=44