====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.5.219/5557 is trying to acquire lock: ffff888027dc4650 (sb_internal){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1891 [inline] ffff888027dc4650 (sb_internal){.+.+}-{0:0}, at: sb_start_intwrite include/linux/fs.h:2013 [inline] ffff888027dc4650 (sb_internal){.+.+}-{0:0}, at: ext4_evict_inode+0x436/0x1100 fs/ext4/inode.c:240 but task is already holding lock: ffff888027dc6b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ext_migrate+0x2c4/0xe50 fs/ext4/migrate.c:437 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 (sb_internal){.+.+}-{0:0}: 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 percpu_down_read+0x44/0x1a0 include/linux/percpu-rwsem.h:51 __sb_start_write include/linux/fs.h:1891 [inline] sb_start_intwrite include/linux/fs.h:2013 [inline] ext4_evict_inode+0x436/0x1100 fs/ext4/inode.c:240 evict+0x485/0x870 fs/inode.c:705 ext4_ext_migrate+0xc0a/0xe50 fs/ext4/migrate.c:587 __ext4_ioctl fs/ext4/ioctl.c:1396 [inline] ext4_ioctl+0x1c1e/0x3dd0 fs/ext4/ioctl.c:1614 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856 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 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); lock(sb_internal); *** DEADLOCK *** 3 locks held by syz.5.219/5557: #0: ffff888027dc4460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write_file+0x5c/0x200 fs/namespace.c:446 #1: ffff8880543aa218 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #1: ffff8880543aa218 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: __ext4_ioctl fs/ext4/ioctl.c:1395 [inline] #1: ffff8880543aa218 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: ext4_ioctl+0x1c16/0x3dd0 fs/ext4/ioctl.c:1614 #2: ffff888027dc6b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ext_migrate+0x2c4/0xe50 fs/ext4/migrate.c:437 stack backtrace: CPU: 0 PID: 5557 Comm: syz.5.219 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 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 percpu_down_read+0x44/0x1a0 include/linux/percpu-rwsem.h:51 __sb_start_write include/linux/fs.h:1891 [inline] sb_start_intwrite include/linux/fs.h:2013 [inline] ext4_evict_inode+0x436/0x1100 fs/ext4/inode.c:240 evict+0x485/0x870 fs/inode.c:705 ext4_ext_migrate+0xc0a/0xe50 fs/ext4/migrate.c:587 __ext4_ioctl fs/ext4/ioctl.c:1396 [inline] ext4_ioctl+0x1c1e/0x3dd0 fs/ext4/ioctl.c:1614 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856 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 RIP: 0033:0x7f052a18f749 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:00007f052b083038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f052a3e6090 RCX: 00007f052a18f749 RDX: 0000000000000000 RSI: 0000000000006609 RDI: 0000000000000004 RBP: 00007f052a213f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f052a3e6128 R14: 00007f052a3e6090 R15: 00007ffc4b6249f8