syzbot

loop0: detected capacity change from 0 to 512
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.17/6063 is trying to acquire lock:
ffff888034078c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: percpu_down_read include/linux/percpu-rwsem.h:77 [inline]
ffff888034078c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1796 [inline]
ffff888034078c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1cc/0x350 fs/ext4/inode.c:3024

but task is already holding lock:
ffff8880574e0c90 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:164 [inline]
ffff8880574e0c90 (&ei->xattr_sem){++++}-{4:4}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:6404 [inline]
ffff8880574e0c90 (&ei->xattr_sem){++++}-{4:4}, at: __ext4_mark_inode_dirty+0x3eb/0x700 fs/ext4/inode.c:6485

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&ei->xattr_sem){++++}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       down_write+0x3a/0x50 kernel/locking/rwsem.c:1590
       ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline]
       ext4_xattr_set_handle+0x165/0x1590 fs/ext4/xattr.c:2367
       ext4_initxattrs+0x9f/0x110 fs/ext4/xattr_security.c:44
       security_inode_init_security+0x2a0/0x3f0 security/security.c:1891
       __ext4_new_inode+0x3314/0x3cb0 fs/ext4/ialloc.c:1325
       ext4_create+0x22d/0x460 fs/ext4/namei.c:2822
       lookup_open fs/namei.c:3796 [inline]
       open_last_lookups fs/namei.c:3895 [inline]
       path_openat+0x1500/0x3840 fs/namei.c:4131
       do_filp_open+0x1fa/0x410 fs/namei.c:4161
       do_sys_openat2+0x121/0x1c0 fs/open.c:1437
       do_sys_open fs/open.c:1452 [inline]
       __do_sys_openat fs/open.c:1468 [inline]
       __se_sys_openat fs/open.c:1463 [inline]
       __x64_sys_openat+0x138/0x170 fs/open.c:1463
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (jbd2_handle){++++}-{0:0}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       start_this_handle+0x1fa7/0x21c0 fs/jbd2/transaction.c:444
       jbd2__journal_start+0x2c1/0x5b0 fs/jbd2/transaction.c:501
       __ext4_journal_start_sb+0x227/0x5c0 fs/ext4/ext4_jbd2.c:115
       __ext4_journal_start fs/ext4/ext4_jbd2.h:242 [inline]
       ext4_do_writepages+0xf6f/0x4600 fs/ext4/inode.c:2913
       ext4_writepages+0x205/0x350 fs/ext4/inode.c:3025
       do_writepages+0x32e/0x550 mm/page-writeback.c:2604
       filemap_fdatawrite_wbc mm/filemap.c:389 [inline]
       __filemap_fdatawrite_range mm/filemap.c:422 [inline]
       file_write_and_wait_range+0x244/0x340 mm/filemap.c:797
       ext4_sync_file+0x2b4/0xb20 fs/ext4/fsync.c:154
       vfs_fsync_range fs/sync.c:187 [inline]
       vfs_fsync fs/sync.c:201 [inline]
       do_fsync fs/sync.c:212 [inline]
       __do_sys_fsync fs/sync.c:217 [inline]
       __se_sys_fsync fs/sync.c:215 [inline]
       __x64_sys_fsync+0x194/0x1f0 fs/sync.c:215
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&sbi->s_writepages_rwsem){++++}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
       __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       percpu_down_read_internal+0x48/0x1d0 include/linux/percpu-rwsem.h:53
       percpu_down_read include/linux/percpu-rwsem.h:77 [inline]
       ext4_writepages_down_read fs/ext4/ext4.h:1796 [inline]
       ext4_writepages+0x1cc/0x350 fs/ext4/inode.c:3024
       do_writepages+0x32e/0x550 mm/page-writeback.c:2604
       __writeback_single_inode+0x145/0x1000 fs/fs-writeback.c:1719
       writeback_single_inode+0x1db/0x640 fs/fs-writeback.c:1840
       write_inode_now+0x160/0x1d0 fs/fs-writeback.c:2903
       iput_final fs/inode.c:1901 [inline]
       iput+0x830/0xc50 fs/inode.c:1966
       ext4_xattr_block_set+0x1fce/0x2ac0 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+0x12da/0x1ea0 fs/ext4/xattr.c:2827
       __ext4_expand_extra_isize+0x30d/0x400 fs/ext4/inode.c:6364
       ext4_try_to_expand_extra_isize fs/ext4/inode.c:6407 [inline]
       __ext4_mark_inode_dirty+0x46c/0x700 fs/ext4/inode.c:6485
       ext4_evict_inode+0x80d/0xee0 fs/ext4/inode.c:254
       evict+0x504/0x9c0 fs/inode.c:810
       ext4_orphan_cleanup+0xc20/0x1460 fs/ext4/orphan.c:470
       __ext4_fill_super fs/ext4/super.c:5617 [inline]
       ext4_fill_super+0x593b/0x61f0 fs/ext4/super.c:5736
       get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1698
       vfs_get_tree+0x92/0x2b0 fs/super.c:1758
       fc_mount fs/namespace.c:1199 [inline]
       do_new_mount_fc fs/namespace.c:3642 [inline]
       do_new_mount+0x302/0xa10 fs/namespace.c:3718
       do_mount fs/namespace.c:4041 [inline]
       __do_sys_mount fs/namespace.c:4229 [inline]
       __se_sys_mount+0x313/0x410 fs/namespace.c:4206
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  &sbi->s_writepages_rwsem --> jbd2_handle --> &ei->xattr_sem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ei->xattr_sem);
                               lock(jbd2_handle);
                               lock(&ei->xattr_sem);
  rlock(&sbi->s_writepages_rwsem);

 *** DEADLOCK ***

3 locks held by syz.0.17/6063:
 #0: ffff8880345460d0 (&type->s_umount_key#26/1){+.+.}-{4:4}, at: alloc_super+0x1ba/0x9a0 fs/super.c:344
 #1: ffff888034546770 (sb_internal){.+.+}-{0:0}, at: percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
 #1: ffff888034546770 (sb_internal){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1916 [inline]
 #1: ffff888034546770 (sb_internal){.+.+}-{0:0}, at: sb_start_intwrite include/linux/fs.h:2099 [inline]
 #1: ffff888034546770 (sb_internal){.+.+}-{0:0}, at: ext4_evict_inode+0x2d6/0xee0 fs/ext4/inode.c:215
 #2: ffff8880574e0c90 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:164 [inline]
 #2: ffff8880574e0c90 (&ei->xattr_sem){++++}-{4:4}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:6404 [inline]
 #2: ffff8880574e0c90 (&ei->xattr_sem){++++}-{4:4}, at: __ext4_mark_inode_dirty+0x3eb/0x700 fs/ext4/inode.c:6485

stack backtrace:
CPU: 0 UID: 0 PID: 6063 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043
 check_noncircular+0x134/0x160 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+0xb9b/0x2140 kernel/locking/lockdep.c:3908
 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
 percpu_down_read_internal+0x48/0x1d0 include/linux/percpu-rwsem.h:53
 percpu_down_read include/linux/percpu-rwsem.h:77 [inline]
 ext4_writepages_down_read fs/ext4/ext4.h:1796 [inline]
 ext4_writepages+0x1cc/0x350 fs/ext4/inode.c:3024
 do_writepages+0x32e/0x550 mm/page-writeback.c:2604
 __writeback_single_inode+0x145/0x1000 fs/fs-writeback.c:1719
 writeback_single_inode+0x1db/0x640 fs/fs-writeback.c:1840
 write_inode_now+0x160/0x1d0 fs/fs-writeback.c:2903
 iput_final fs/inode.c:1901 [inline]
 iput+0x830/0xc50 fs/inode.c:1966
 ext4_xattr_block_set+0x1fce/0x2ac0 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+0x12da/0x1ea0 fs/ext4/xattr.c:2827
 __ext4_expand_extra_isize+0x30d/0x400 fs/ext4/inode.c:6364
 ext4_try_to_expand_extra_isize fs/ext4/inode.c:6407 [inline]
 __ext4_mark_inode_dirty+0x46c/0x700 fs/ext4/inode.c:6485
 ext4_evict_inode+0x80d/0xee0 fs/ext4/inode.c:254
 evict+0x504/0x9c0 fs/inode.c:810
 ext4_orphan_cleanup+0xc20/0x1460 fs/ext4/orphan.c:470
 __ext4_fill_super fs/ext4/super.c:5617 [inline]
 ext4_fill_super+0x593b/0x61f0 fs/ext4/super.c:5736
 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1698
 vfs_get_tree+0x92/0x2b0 fs/super.c:1758
 fc_mount fs/namespace.c:1199 [inline]
 do_new_mount_fc fs/namespace.c:3642 [inline]
 do_new_mount+0x302/0xa10 fs/namespace.c:3718
 do_mount fs/namespace.c:4041 [inline]
 __do_sys_mount fs/namespace.c:4229 [inline]
 __se_sys_mount+0x313/0x410 fs/namespace.c:4206
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f82f99f0e6a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007ffc4fb98f38 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffc4fb98fc0 RCX: 00007f82f99f0e6a
RDX: 0000200000000180 RSI: 00002000000001c0 RDI: 00007ffc4fb98f80
RBP: 0000200000000180 R08: 00007ffc4fb98fc0 R09: 0000000000800700
R10: 0000000000800700 R11: 0000000000000246 R12: 00002000000001c0
R13: 00007ffc4fb98f80 R14: 000000000000046f R15: 000000000000002c
 </TASK>
------------[ cut here ]------------
EA inode 11 i_nlink=2
WARNING: CPU: 1 PID: 6063 at fs/ext4/xattr.c:1058 ext4_xattr_inode_update_ref+0x51a/0x5b0 fs/ext4/xattr.c:1056
Modules linked in:
CPU: 1 UID: 0 PID: 6063 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:ext4_xattr_inode_update_ref+0x51a/0x5b0 fs/ext4/xattr.c:1056
Code: 48 b8 00 00 00 00 00 fc ff df 41 0f b6 04 06 84 c0 0f 85 80 00 00 00 41 8b 17 48 c7 c7 40 9b ff 8a 4c 89 e6 e8 07 92 03 ff 90 <0f> 0b 90 90 4c 8b 6c 24 28 e9 59 fe ff ff e8 83 2e 41 08 44 89 f9
RSP: 0018:ffffc90003cbf100 EFLAGS: 00010246
RAX: 7eeb07df16040e00 RBX: 0000000000000001 RCX: ffff888025403c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003cbf1f8 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed101712487b R12: 000000000000000b
R13: ffff888041316ee8 R14: 1ffff11008262dc3 R15: ffff888041316e18
FS:  0000555561e31500(0000) GS:ffff888126ef7000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc4455f17e8 CR3: 0000000033a46000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 ext4_xattr_inode_dec_ref fs/ext4/xattr.c:1081 [inline]
 ext4_xattr_set_entry+0xabb/0x1e20 fs/ext4/xattr.c:1719
 ext4_xattr_ibody_set+0x254/0x6a0 fs/ext4/xattr.c:2268
 ext4_xattr_move_to_block fs/ext4/xattr.c:2671 [inline]
 ext4_xattr_make_inode_space fs/ext4/xattr.c:2739 [inline]
 ext4_expand_extra_isize_ea+0x13ad/0x1ea0 fs/ext4/xattr.c:2827
 __ext4_expand_extra_isize+0x30d/0x400 fs/ext4/inode.c:6364
 ext4_try_to_expand_extra_isize fs/ext4/inode.c:6407 [inline]
 __ext4_mark_inode_dirty+0x46c/0x700 fs/ext4/inode.c:6485
 ext4_evict_inode+0x80d/0xee0 fs/ext4/inode.c:254
 evict+0x504/0x9c0 fs/inode.c:810
 ext4_orphan_cleanup+0xc20/0x1460 fs/ext4/orphan.c:470
 __ext4_fill_super fs/ext4/super.c:5617 [inline]
 ext4_fill_super+0x593b/0x61f0 fs/ext4/super.c:5736
 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1698
 vfs_get_tree+0x92/0x2b0 fs/super.c:1758
 fc_mount fs/namespace.c:1199 [inline]
 do_new_mount_fc fs/namespace.c:3642 [inline]
 do_new_mount+0x302/0xa10 fs/namespace.c:3718
 do_mount fs/namespace.c:4041 [inline]
 __do_sys_mount fs/namespace.c:4229 [inline]
 __se_sys_mount+0x313/0x410 fs/namespace.c:4206
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f82f99f0e6a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007ffc4fb98f38 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffc4fb98fc0 RCX: 00007f82f99f0e6a
RDX: 0000200000000180 RSI: 00002000000001c0 RDI: 00007ffc4fb98f80
RBP: 0000200000000180 R08: 00007ffc4fb98fc0 R09: 0000000000800700
R10: 0000000000800700 R11: 0000000000000246 R12: 00002000000001c0
R13: 00007ffc4fb98f80 R14: 000000000000046f R15: 000000000000002c
 </TASK>