======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.3.2051/12921 is trying to acquire lock:
ffff8880614f8090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27

but task is already holding lock:
ffff888025a62b28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
ffff888025a62b28 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x16c/0x2d0 mm/util.c:549

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&mm->mmap_lock){++++}-{3:3}:
       __might_fault+0xb3/0x110 mm/memory.c:5357
       reiserfs_ioctl+0x13b/0x330 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

-> #0 (&sbi->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+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
       lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1e3/0x2400 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
       reiserfs_dirty_inode+0x10d/0x260 fs/reiserfs/super.c:704
       __mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2480
       generic_update_time fs/inode.c:1881 [inline]
       inode_update_time fs/inode.c:1894 [inline]
       touch_atime+0x3b6/0x640 fs/inode.c:1966
       file_accessed include/linux/fs.h:2522 [inline]
       generic_file_mmap+0xc1/0x120 mm/filemap.c:3401
       call_mmap include/linux/fs.h:2178 [inline]
       mmap_file+0x5d/0xb0 mm/util.c:1092
       __mmap_region mm/mmap.c:1796 [inline]
       mmap_region+0xf88/0x1650 mm/mmap.c:2933
       do_mmap+0x819/0xe90 mm/mmap.c:1586
       vm_mmap_pgoff+0x1c1/0x2d0 mm/util.c:551
       ksys_mmap_pgoff+0x54b/0x790 mm/mmap.c:1635
       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(&mm->mmap_lock);
                               lock(&sbi->lock);
                               lock(&mm->mmap_lock);
  lock(&sbi->lock);

 *** DEADLOCK ***

2 locks held by syz.3.2051/12921:
 #0: ffff888025a62b28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
 #0: ffff888025a62b28 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x16c/0x2d0 mm/util.c:549
 #1: ffff88806888c460 (sb_writers#28){.+.+}-{0:0}, at: file_accessed include/linux/fs.h:2522 [inline]
 #1: ffff88806888c460 (sb_writers#28){.+.+}-{0:0}, at: generic_file_mmap+0xc1/0x120 mm/filemap.c:3401

stack backtrace:
CPU: 0 PID: 12921 Comm: syz.3.2051 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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
 __mutex_lock_common+0x1e3/0x2400 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
 reiserfs_dirty_inode+0x10d/0x260 fs/reiserfs/super.c:704
 __mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2480
 generic_update_time fs/inode.c:1881 [inline]
 inode_update_time fs/inode.c:1894 [inline]
 touch_atime+0x3b6/0x640 fs/inode.c:1966
 file_accessed include/linux/fs.h:2522 [inline]
 generic_file_mmap+0xc1/0x120 mm/filemap.c:3401
 call_mmap include/linux/fs.h:2178 [inline]
 mmap_file+0x5d/0xb0 mm/util.c:1092
 __mmap_region mm/mmap.c:1796 [inline]
 mmap_region+0xf88/0x1650 mm/mmap.c:2933
 do_mmap+0x819/0xe90 mm/mmap.c:1586
 vm_mmap_pgoff+0x1c1/0x2d0 mm/util.c:551
 ksys_mmap_pgoff+0x54b/0x790 mm/mmap.c:1635
 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: 0033:0x7f9436a94f79
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:00007f9434cad028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f9436d0f180 RCX: 00007f9436a94f79
RDX: 0000000002000001 RSI: 0000000000003000 RDI: 0000200000000000
RBP: 00007f9436b2b7e0 R08: 000000000000000a R09: 0000000000000000
R10: 0000000000000012 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9436d0f218 R14: 00007f9436d0f180 R15: 00007ffde66b74d8
 </TASK>