syzbot

loop1: detected capacity change from 0 to 2048
EXT4-fs (loop1): mounted filesystem without journal. Opts: delalloc,noload,acl,mb_optimize_scan=0x0000000000000001,,errors=continue. Quota mode: none.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.1.157/4908 is trying to acquire lock:
ffff888074553c98 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:158 [inline]
ffff888074553c98 (&ei->xattr_sem){++++}-{3:3}, at: ext4_destroy_inline_data+0x24/0xe0 fs/ext4/inline.c:1900

but task is already holding lock:
ffff888148018c58 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x20f/0x2df0 fs/ext4/inode.c:2691

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+0x46/0x1b0 include/linux/percpu-rwsem.h:51
       ext4_writepages+0x20f/0x2df0 fs/ext4/inode.c:2691
       do_writepages+0x476/0x6e0 mm/page-writeback.c:2386
       __writeback_single_inode+0x153/0xda0 fs/fs-writeback.c:1657
       writeback_single_inode+0x3cb/0x8e0 fs/fs-writeback.c:1770
       write_inode_now+0x23b/0x2c0 fs/fs-writeback.c:2817
       iput_final fs/inode.c:1756 [inline]
       iput+0x5ab/0x8a0 fs/inode.c:1795
       ext4_xattr_set_entry+0x34f4/0x3ea0 fs/ext4/xattr.c:1825
       ext4_xattr_block_set+0x4fd/0x2d20 fs/ext4/xattr.c:1924
       ext4_xattr_move_to_block fs/ext4/xattr.c:2618 [inline]
       ext4_xattr_make_inode_space fs/ext4/xattr.c:2693 [inline]
       ext4_expand_extra_isize_ea+0xf3f/0x19b0 fs/ext4/xattr.c:2781
       __ext4_expand_extra_isize+0x301/0x3e0 fs/ext4/inode.c:5924
       ext4_try_to_expand_extra_isize fs/ext4/inode.c:5967 [inline]
       __ext4_mark_inode_dirty+0x469/0x700 fs/ext4/inode.c:6045
       ext4_evict_inode+0xa8d/0x1090 fs/ext4/inode.c:284
       evict+0x4c9/0x8d0 fs/inode.c:647
       ext4_orphan_cleanup+0xad2/0x1320 fs/ext4/orphan.c:472
       ext4_fill_super+0x8d6e/0x94f0 fs/ext4/super.c:5006
       mount_bdev+0x287/0x3c0 fs/super.c:1400
       legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
       vfs_get_tree+0x88/0x270 fs/super.c:1530
       do_new_mount+0x24a/0xa40 fs/namespace.c:3034
       do_mount fs/namespace.c:3377 [inline]
       __do_sys_mount fs/namespace.c:3585 [inline]
       __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (&ei->xattr_sem){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
       lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       ext4_write_lock_xattr fs/ext4/xattr.h:158 [inline]
       ext4_destroy_inline_data+0x24/0xe0 fs/ext4/inline.c:1900
       ext4_writepages+0x670/0x2df0 fs/ext4/inode.c:2737
       do_writepages+0x476/0x6e0 mm/page-writeback.c:2386
       filemap_fdatawrite_wbc+0x1eb/0x240 mm/filemap.c:400
       __filemap_fdatawrite_range mm/filemap.c:433 [inline]
       __filemap_fdatawrite mm/filemap.c:439 [inline]
       filemap_flush+0xd4/0x130 mm/filemap.c:466
       ext4_convert_inline_data+0x18b/0x5f0 fs/ext4/inline.c:2076
       ext4_page_mkwrite+0x1df/0x1250 fs/ext4/inode.c:6199
       do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
       do_shared_fault mm/memory.c:4328 [inline]
       do_fault mm/memory.c:4396 [inline]
       handle_pte_fault mm/memory.c:4650 [inline]
       __handle_mm_fault mm/memory.c:4785 [inline]
       handle_mm_fault+0x1d87/0x4410 mm/memory.c:4883
       do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1355
       handle_page_fault arch/x86/mm/fault.c:1443 [inline]
       exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
       asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
       copy_user_enhanced_fast_string+0xe/0x40 arch/x86/lib/copy_user_64.S:205
       copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
       raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline]
       copyout lib/iov_iter.c:157 [inline]
       _copy_to_iter+0x318/0x1180 lib/iov_iter.c:669
       copy_to_iter include/linux/uio.h:155 [inline]
       get_random_bytes_user+0x1cc/0x3d0 drivers/char/random.c:474
       __do_sys_getrandom drivers/char/random.c:1242 [inline]
       __se_sys_getrandom drivers/char/random.c:1215 [inline]
       __x64_sys_getrandom+0x1c2/0x2a0 drivers/char/random.c:1215
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

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 ***

4 locks held by syz.1.157/4908:
 #0: ffff88807b884e28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock+0x1c/0x50 include/linux/mmap_lock.h:117
 #1: ffff88814801c558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
 #1: ffff88814801c558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
 #1: ffff88814801c558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
 #2: ffff888074554160 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:842 [inline]
 #2: ffff888074554160 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_page_mkwrite+0x1d2/0x1250 fs/ext4/inode.c:6197
 #3: ffff888148018c58 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x20f/0x2df0 fs/ext4/inode.c:2691

stack backtrace:
CPU: 1 PID: 4908 Comm: syz.1.157 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 down_write+0x38/0x60 kernel/locking/rwsem.c:1551
 ext4_write_lock_xattr fs/ext4/xattr.h:158 [inline]
 ext4_destroy_inline_data+0x24/0xe0 fs/ext4/inline.c:1900
 ext4_writepages+0x670/0x2df0 fs/ext4/inode.c:2737
 do_writepages+0x476/0x6e0 mm/page-writeback.c:2386
 filemap_fdatawrite_wbc+0x1eb/0x240 mm/filemap.c:400
 __filemap_fdatawrite_range mm/filemap.c:433 [inline]
 __filemap_fdatawrite mm/filemap.c:439 [inline]
 filemap_flush+0xd4/0x130 mm/filemap.c:466
 ext4_convert_inline_data+0x18b/0x5f0 fs/ext4/inline.c:2076
 ext4_page_mkwrite+0x1df/0x1250 fs/ext4/inode.c:6199
 do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
 do_shared_fault mm/memory.c:4328 [inline]
 do_fault mm/memory.c:4396 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x1d87/0x4410 mm/memory.c:4883
 do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1355
 handle_page_fault arch/x86/mm/fault.c:1443 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0010:copy_user_enhanced_fast_string+0xe/0x40 arch/x86/lib/copy_user_64.S:206
Code: 89 d1 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 31 c0 0f 01 ca c3 90 90 90 90 90 90 90 0f 01 cb 83 fa 40 0f 82 70 ff ff ff 89 d1 <f3> a4 31 c0 0f 01 ca c3 90 90 90 90 90 90 90 90 90 90 89 d1 83 f8
RSP: 0018:ffffc900034cfb38 EFLAGS: 00050246
RAX: ffffffff83e1c601 RBX: 0000000000000040 RCX: 0000000000000040
RDX: 0000000000000040 RSI: ffffc900034cfd40 RDI: 0000200000000240
RBP: ffffc900034cfc90 R08: ffffc900034cfd7f R09: 1ffff92000699faf
R10: dffffc0000000000 R11: fffff52000699fb0 R12: ffffc900034cfd40
R13: dffffc00000000ff R14: 0000200000000240 R15: 0000000000000000
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline]
 copyout lib/iov_iter.c:157 [inline]
 _copy_to_iter+0x318/0x1180 lib/iov_iter.c:669
 copy_to_iter include/linux/uio.h:155 [inline]
 get_random_bytes_user+0x1cc/0x3d0 drivers/char/random.c:474
 __do_sys_getrandom drivers/char/random.c:1242 [inline]
 __se_sys_getrandom drivers/char/random.c:1215 [inline]
 __x64_sys_getrandom+0x1c2/0x2a0 drivers/char/random.c:1215
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fd08ab07dd9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd088d61028 EFLAGS: 00000246 ORIG_RAX: 000000000000013e
RAX: ffffffffffffffda RBX: 00007fd08ad80fa0 RCX: 00007fd08ab07dd9
RDX: 0100000000000001 RSI: 000000000000011e RDI: 0000200000000240
RBP: 00007fd08ab9dd69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd08ad81038 R14: 00007fd08ad80fa0 R15: 00007fffd98d7f08
 </TASK>
EXT4-fs error (device loop1): ext4_mb_generate_buddy:1176: group 0, block bitmap and bg descriptor inconsistent: 0 vs 150994969 free clusters
EXT4-fs (loop1): Delayed block allocation failed for inode 18 at logical offset 0 with max blocks 1 with error 28
EXT4-fs (loop1): This should not happen!! Data will be lost

EXT4-fs (loop1): Total free blocks count 0
EXT4-fs (loop1): Free/Dirty block details
EXT4-fs (loop1): free_blocks=2415919504
EXT4-fs (loop1): dirty_blocks=16
EXT4-fs (loop1): Block reservation details
EXT4-fs (loop1): i_reserved_data_blocks=1
----------------
Code disassembly (best guess):
   0:	89 d1                	mov    %edx,%ecx
   2:	c1 e9 03             	shr    $0x3,%ecx
   5:	83 e2 07             	and    $0x7,%edx
   8:	f3 48 a5             	rep movsq %ds:(%rsi),%es:(%rdi)
   b:	89 d1                	mov    %edx,%ecx
   d:	f3 a4                	rep movsb %ds:(%rsi),%es:(%rdi)
   f:	31 c0                	xor    %eax,%eax
  11:	0f 01 ca             	clac
  14:	c3                   	ret
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	90                   	nop
  1c:	0f 01 cb             	stac
  1f:	83 fa 40             	cmp    $0x40,%edx
  22:	0f 82 70 ff ff ff    	jb     0xffffff98
  28:	89 d1                	mov    %edx,%ecx
* 2a:	f3 a4                	rep movsb %ds:(%rsi),%es:(%rdi) <-- trapping instruction
  2c:	31 c0                	xor    %eax,%eax
  2e:	0f 01 ca             	clac
  31:	c3                   	ret
  32:	90                   	nop
  33:	90                   	nop
  34:	90                   	nop
  35:	90                   	nop
  36:	90                   	nop
  37:	90                   	nop
  38:	90                   	nop
  39:	90                   	nop
  3a:	90                   	nop
  3b:	90                   	nop
  3c:	89 d1                	mov    %edx,%ecx
  3e:	83                   	.byte 0x83
  3f:	f8                   	clc