loop4: detected capacity change from 0 to 128 EXT4-fs (loop4): mounted filesystem 76b65be2-f6da-4727-8c75-0525a5b65a09 r/w without journal. Quota mode: none. ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.4.236/6158 is trying to acquire lock: ffff0000dd755520 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline] ffff0000dd755520 (&ei->xattr_sem){++++}-{4:4}, at: ext4_xattr_set_handle+0x138/0xe00 fs/ext4/xattr.c:2374 but task is already holding lock: ffff0000d9b98c18 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_write fs/ext4/ext4.h:1823 [inline] ffff0000d9b98c18 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ext_migrate+0x280/0xc58 fs/ext4/migrate.c:438 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+0x5c/0x294 include/linux/percpu-rwsem.h:53 percpu_down_read include/linux/percpu-rwsem.h:77 [inline] ext4_writepages_down_read fs/ext4/ext4.h:1811 [inline] ext4_writepages+0x16c/0x2d8 fs/ext4/inode.c:3041 do_writepages+0x270/0x468 mm/page-writeback.c:2571 __writeback_single_inode+0x144/0x1808 fs/fs-writeback.c:1764 writeback_single_inode+0x3b8/0xaa0 fs/fs-writeback.c:1883 write_inode_now+0x170/0x208 fs/fs-writeback.c:2974 iput_final fs/inode.c:1950 [inline] iput+0x6bc/0xb90 fs/inode.c:2009 ext4_xattr_block_set+0x12dc/0x2188 fs/ext4/xattr.c:2206 ext4_xattr_move_to_block fs/ext4/xattr.c:2671 [inline] ext4_xattr_make_inode_space fs/ext4/xattr.c:2746 [inline] ext4_expand_extra_isize_ea+0xb18/0x13a0 fs/ext4/xattr.c:2834 __ext4_expand_extra_isize+0x29c/0x370 fs/ext4/inode.c:6434 ext4_try_to_expand_extra_isize fs/ext4/inode.c:6477 [inline] __ext4_mark_inode_dirty+0x3a4/0x810 fs/ext4/inode.c:6555 ext4_evict_inode+0x7a0/0xfc4 fs/ext4/inode.c:267 evict+0x4b8/0x740 fs/inode.c:841 iput_final fs/inode.c:1960 [inline] iput+0x858/0xb90 fs/inode.c:2009 ext4_process_orphan+0x240/0x2b4 fs/ext4/orphan.c:358 ext4_orphan_cleanup+0x7b8/0xd30 fs/ext4/orphan.c:472 __ext4_fill_super fs/ext4/super.c:5701 [inline] ext4_fill_super+0x45a4/0x4d60 fs/ext4/super.c:5824 get_tree_bdev_flags+0x380/0x434 fs/super.c:1694 get_tree_bdev+0x2c/0x3c fs/super.c:1717 ext4_get_tree+0x28/0x38 fs/ext4/super.c:5856 vfs_get_tree+0x90/0x28c fs/super.c:1754 fc_mount+0x24/0xac fs/namespace.c:1193 do_new_mount_fc fs/namespace.c:3758 [inline] do_new_mount+0x2a4/0x540 fs/namespace.c:3834 path_mount+0x5d0/0xa68 fs/namespace.c:4154 do_mount+0xe8/0x148 fs/namespace.c:4167 __do_sys_mount fs/namespace.c:4383 [inline] __se_sys_mount fs/namespace.c:4360 [inline] __arm64_sys_mount+0x334/0x380 fs/namespace.c:4360 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:740 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:759 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 -> #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+0x1780/0x2f44 kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x368 kernel/locking/lockdep.c:5868 down_write+0x50/0xc0 kernel/locking/rwsem.c:1625 ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline] ext4_xattr_set_handle+0x138/0xe00 fs/ext4/xattr.c:2374 ext4_initxattrs+0xa4/0x118 fs/ext4/xattr_security.c:44 security_inode_init_security+0x24c/0x378 security/security.c:1370 ext4_init_security+0x44/0x58 fs/ext4/xattr_security.c:58 __ext4_new_inode+0x28dc/0x3390 fs/ext4/ialloc.c:1330 ext4_ext_migrate+0x56c/0xc58 fs/ext4/migrate.c:462 __ext4_ioctl fs/ext4/ioctl.c:1693 [inline] ext4_ioctl+0x1cd4/0x4234 fs/ext4/ioctl.c:1922 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:740 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:759 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 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 syz.4.236/6158: #0: ffff0000db4f2410 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0xdc fs/namespace.c:537 #1: ffff0000dd751638 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline] #1: ffff0000dd751638 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: __ext4_ioctl fs/ext4/ioctl.c:1692 [inline] #1: ffff0000dd751638 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: ext4_ioctl+0x1ccc/0x4234 fs/ext4/ioctl.c:1922 #2: ffff0000d9b98c18 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_write fs/ext4/ext4.h:1823 [inline] #2: ffff0000d9b98c18 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ext_migrate+0x280/0xc58 fs/ext4/migrate.c:438 stack backtrace: CPU: 0 UID: 0 PID: 6158 Comm: syz.4.236 Not tainted syzkaller #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x328/0x330 kernel/locking/lockdep.c:2043 check_noncircular+0x158/0x174 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+0x1780/0x2f44 kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x368 kernel/locking/lockdep.c:5868 down_write+0x50/0xc0 kernel/locking/rwsem.c:1625 ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline] ext4_xattr_set_handle+0x138/0xe00 fs/ext4/xattr.c:2374 ext4_initxattrs+0xa4/0x118 fs/ext4/xattr_security.c:44 security_inode_init_security+0x24c/0x378 security/security.c:1370 ext4_init_security+0x44/0x58 fs/ext4/xattr_security.c:58 __ext4_new_inode+0x28dc/0x3390 fs/ext4/ialloc.c:1330 ext4_ext_migrate+0x56c/0xc58 fs/ext4/migrate.c:462 __ext4_ioctl fs/ext4/ioctl.c:1693 [inline] ext4_ioctl+0x1cd4/0x4234 fs/ext4/ioctl.c:1922 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:740 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:759 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594