syzbot

REISERFS (device loop2): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
5.15.189-syzkaller #0 Not tainted
------------------------------------------------------
syz.2.19/4417 is trying to acquire lock:
ffff88805d5bd090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27

but task is already holding lock:
ffff888025482558 (sb_pagefaults#2){.+.+}-{0:0}, at: do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (sb_pagefaults#2){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1811 [inline]
       sb_start_pagefault include/linux/fs.h:1910 [inline]
       filemap_page_mkwrite+0x120/0x660 mm/filemap.c:3367
       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+0x1d4b/0x43c0 mm/memory.c:4883
       do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1357
       handle_page_fault arch/x86/mm/fault.c:1445 [inline]
       exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501
       asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606

-> #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+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
       lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1eb/0x2390 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+0xf0/0x240 fs/reiserfs/super.c:704
       __mark_inode_dirty+0x2b0/0xc60 fs/fs-writeback.c:2464
       generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
       inode_update_time fs/inode.c:1894 [inline]
       file_update_time+0x38b/0x400 fs/inode.c:2083
       filemap_page_mkwrite+0x242/0x660 mm/filemap.c:3368
       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+0x1d4b/0x43c0 mm/memory.c:4883
       do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1357
       handle_page_fault arch/x86/mm/fault.c:1445 [inline]
       exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501
       asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606

other info that might help us debug this:

Chain exists of:
  &sbi->lock --> &mm->mmap_lock --> sb_pagefaults#2

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_pagefaults#2);
                               lock(&mm->mmap_lock);
                               lock(sb_pagefaults#2);
  lock(&sbi->lock);

 *** DEADLOCK ***

2 locks held by syz.2.19/4417:
 #0: ffff88807b712428
 (&mm->mmap_lock
){++++}-{3:3}, at: mmap_read_lock+0x1c/0x50 include/linux/mmap_lock.h:117
 #1: ffff888025482558 (sb_pagefaults#2){.+.+}-{0:0}
, at: do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922

stack backtrace:
CPU: 1 PID: 4417 Comm: syz.2.19 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 check_noncircular+0x274/0x310 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+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 __mutex_lock_common+0x1eb/0x2390 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+0xf0/0x240 fs/reiserfs/super.c:704
 __mark_inode_dirty+0x2b0/0xc60 fs/fs-writeback.c:2464
 generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
 inode_update_time fs/inode.c:1894 [inline]
 file_update_time+0x38b/0x400 fs/inode.c:2083
 filemap_page_mkwrite+0x242/0x660 mm/filemap.c:3368
 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+0x1d4b/0x43c0 mm/memory.c:4883
 do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1357
 handle_page_fault arch/x86/mm/fault.c:1445 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7fb6e42b292b
Code: fa 10 73 2d 83 fa 08 73 46 83 fa 04 73 16 83 fa 01 7c 10 8a 0e 74 0a 0f b7 74 16 fe 66 89 74 17 fe 88 0f c3 8b 4c 16 fc 8b 36 <89> 4c 17 fc 89 37 c3 c5 fa 6f 06 c5 fa 6f 4c 16 f0 c5 fa 7f 07 c5
RSP: 002b:00007ffc5b6cbe58 EFLAGS: 00010202
RAX: 0000200000000400 RBX: 0000000000000004 RCX: 0000000000737562
RDX: 0000000000000006 RSI: 0000000075622f2e RDI: 0000200000000400
RBP: 0000000000000000 R08: 0000001b31720000 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000009 R12: 00007fb6e4511fac
R13: 00007fb6e4511fa0 R14: fffffffffffffffe R15: 0000000000000006
 </TASK>