====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.1.1996/13384 is trying to acquire lock: ffff888029c38610 (sb_internal){++++}-{0:0}, at: evict+0x3c2/0xad0 fs/inode.c:837 but task is already holding lock: ffff888029c3ab98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_write fs/ext4/ext4.h:1808 [inline] ffff888029c3ab98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ext_migrate+0x39c/0x1ee0 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 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:1796 [inline] ext4_writepages+0x224/0x7d0 fs/ext4/inode.c:3020 do_writepages+0x27a/0x600 mm/page-writeback.c:2598 __writeback_single_inode+0x168/0x14a0 fs/fs-writeback.c:1737 writeback_single_inode+0x5ea/0x11f0 fs/fs-writeback.c:1858 write_inode_now+0x170/0x1e0 fs/fs-writeback.c:2924 iput_final fs/inode.c:1941 [inline] iput.part.0+0x815/0x1190 fs/inode.c:2003 iput+0x35/0x40 fs/inode.c:1966 ext4_xattr_block_set+0x67c/0x3640 fs/ext4/xattr.c:2199 ext4_xattr_move_to_block fs/ext4/xattr.c:2664 [inline] ext4_xattr_make_inode_space fs/ext4/xattr.c:2739 [inline] ext4_expand_extra_isize_ea+0x1442/0x1ab0 fs/ext4/xattr.c:2827 __ext4_expand_extra_isize+0x346/0x480 fs/ext4/inode.c:6360 ext4_try_to_expand_extra_isize fs/ext4/inode.c:6403 [inline] __ext4_mark_inode_dirty+0x544/0x840 fs/ext4/inode.c:6481 ext4_evict_inode+0x713/0x1730 fs/ext4/inode.c:253 evict+0x3c2/0xad0 fs/inode.c:837 iput_final fs/inode.c:1951 [inline] iput.part.0+0x621/0x1190 fs/inode.c:2003 iput+0x35/0x40 fs/inode.c:1966 ext4_orphan_cleanup+0x731/0x11e0 fs/ext4/orphan.c:470 __ext4_fill_super fs/ext4/super.c:5617 [inline] ext4_fill_super+0x91b3/0xb670 fs/ext4/super.c:5736 get_tree_bdev_flags+0x38c/0x620 fs/super.c:1699 vfs_get_tree+0x8e/0x330 fs/super.c:1759 fc_mount fs/namespace.c:1199 [inline] do_new_mount_fc fs/namespace.c:3636 [inline] do_new_mount fs/namespace.c:3712 [inline] path_mount+0x7bf/0x23a0 fs/namespace.c:4022 do_mount fs/namespace.c:4035 [inline] __do_sys_mount fs/namespace.c:4224 [inline] __se_sys_mount fs/namespace.c:4201 [inline] __x64_sys_mount+0x293/0x310 fs/namespace.c:4201 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (sb_internal){++++}-{0:0}: 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+0x1542/0x22f0 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] __sb_start_write include/linux/fs/super.h:19 [inline] sb_start_intwrite include/linux/fs/super.h:177 [inline] ext4_evict_inode+0xccd/0x1730 fs/ext4/inode.c:214 evict+0x3c2/0xad0 fs/inode.c:837 iput_final fs/inode.c:1951 [inline] iput.part.0+0x621/0x1190 fs/inode.c:2003 iput+0x35/0x40 fs/inode.c:1966 ext4_ext_migrate+0xc6f/0x1ee0 fs/ext4/migrate.c:588 __ext4_ioctl+0x3178/0x4410 fs/ext4/ioctl.c:1694 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sbi->s_writepages_rwsem); lock(sb_internal); lock(&sbi->s_writepages_rwsem); rlock(sb_internal); *** DEADLOCK *** 3 locks held by syz.1.1996/13384: #0: ffff888029c38420 (sb_writers#4){++++}-{0:0}, at: __ext4_ioctl+0x3146/0x4410 fs/ext4/ioctl.c:1684 #1: ffff888051121700 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #1: ffff888051121700 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: __ext4_ioctl+0x3170/0x4410 fs/ext4/ioctl.c:1693 #2: ffff888029c3ab98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_write fs/ext4/ext4.h:1808 [inline] #2: ffff888029c3ab98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ext_migrate+0x39c/0x1ee0 fs/ext4/migrate.c:438 stack backtrace: CPU: 1 UID: 0 PID: 13384 Comm: syz.1.1996 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x2db/0x410 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+0x1542/0x22f0 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] __sb_start_write include/linux/fs/super.h:19 [inline] sb_start_intwrite include/linux/fs/super.h:177 [inline] ext4_evict_inode+0xccd/0x1730 fs/ext4/inode.c:214 evict+0x3c2/0xad0 fs/inode.c:837 iput_final fs/inode.c:1951 [inline] iput.part.0+0x621/0x1190 fs/inode.c:2003 iput+0x35/0x40 fs/inode.c:1966 ext4_ext_migrate+0xc6f/0x1ee0 fs/ext4/migrate.c:588 __ext4_ioctl+0x3178/0x4410 fs/ext4/ioctl.c:1694 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f62f8d8f749 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:00007f62f9cad038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f62f8fe6090 RCX: 00007f62f8d8f749 RDX: 0000000000000000 RSI: 0000000000006609 RDI: 0000000000000005 RBP: 00007f62f8e13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f62f8fe6128 R14: 00007f62f8fe6090 R15: 00007ffd66a35e78