syzbot

REISERFS (device loop7): Using tea hash to sort names
REISERFS (device loop7): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.7.4076/19672 is trying to acquire lock:
ffff8880239d6a28 (&mm->mmap_lock){++++}-{3:3}, at: __might_fault+0x90/0x110 mm/memory.c:5356

but task is already holding lock:
ffff888074a63090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&sbi->lock){+.+.}-{3:3}:
       __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
       map_block_for_writepage fs/reiserfs/inode.c:2396 [inline]
       reiserfs_write_full_page fs/reiserfs/inode.c:2593 [inline]
       reiserfs_writepage+0xa46/0x3030 fs/reiserfs/inode.c:2745
       writeout mm/migrate.c:837 [inline]
       fallback_migrate_page mm/migrate.c:861 [inline]
       move_to_new_page+0x85e/0xd80 mm/migrate.c:912
       __unmap_and_move mm/migrate.c:1077 [inline]
       unmap_and_move mm/migrate.c:1218 [inline]
       migrate_pages+0x1fa9/0x34a0 mm/migrate.c:1493
       do_mbind mm/mempolicy.c:1325 [inline]
       kernel_mbind mm/mempolicy.c:1472 [inline]
       __do_sys_mbind mm/mempolicy.c:1479 [inline]
       __se_sys_mbind+0x64c/0x770 mm/mempolicy.c:1475
       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 (&mm->mmap_lock){++++}-{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+0x2c66/0x7b50 kernel/locking/lockdep.c:5012
       lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
       __might_fault+0xb3/0x110 mm/memory.c:5357
       reiserfs_ioctl+0x13b/0x320 fs/reiserfs/ioctl.c:96
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
       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->lock);
                               lock(&mm->mmap_lock);
                               lock(&sbi->lock);
  lock(&mm->mmap_lock);

 *** DEADLOCK ***

1 lock held by syz.7.4076/19672:
 #0: ffff888074a63090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27

stack backtrace:
CPU: 0 PID: 19672 Comm: syz.7.4076 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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+0x2c66/0x7b50 kernel/locking/lockdep.c:5012
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 __might_fault+0xb3/0x110 mm/memory.c:5357
 reiserfs_ioctl+0x13b/0x320 fs/reiserfs/ioctl.c:96
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
 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: 0033:0x7f07017dee59
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:00007f06ffa38028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f0701a57fa0 RCX: 00007f07017dee59
RDX: 0000200000000080 RSI: 0000000080087601 RDI: 0000000000000009
RBP: 00007f0701874e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0701a58038 R14: 00007f0701a57fa0 R15: 00007fffc69c5368
 </TASK>