syzbot

REISERFS (device loop0): checking transaction log (loop0)
REISERFS (device loop0): Using tea hash to sort names
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.219/4834 is trying to acquire lock:
ffff888026e6d090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27

but task is already holding lock:
ffff888078b6a558 (sb_pagefaults#2){.+.+}-{0:0}, at: do_page_mkwrite+0x16b/0x5c0 mm/memory.c:3009

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:1891 [inline]
       sb_start_pagefault include/linux/fs.h:1995 [inline]
       filemap_page_mkwrite+0x167/0x630 mm/filemap.c:3545
       do_page_mkwrite+0x16b/0x5c0 mm/memory.c:3009
       do_shared_fault mm/memory.c:4694 [inline]
       do_fault mm/memory.c:4762 [inline]
       handle_pte_fault mm/memory.c:5029 [inline]
       __handle_mm_fault mm/memory.c:5171 [inline]
       handle_mm_fault+0x1b10/0x3e60 mm/memory.c:5292
       do_user_addr_fault+0x51f/0xb10 arch/x86/mm/fault.c:1340
       handle_page_fault arch/x86/mm/fault.c:1431 [inline]
       exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1487
       asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608

-> #1 (&mm->mmap_lock){++++}-{3:3}:
       __might_fault+0xc2/0x120 mm/memory.c:5850
       reiserfs_ioctl+0x13b/0x330 fs/reiserfs/ioctl.c:96
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&sbi->lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
       lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
       reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
       reiserfs_dirty_inode+0xf0/0x240 fs/reiserfs/super.c:704
       __mark_inode_dirty+0x2eb/0xe90 fs/fs-writeback.c:2443
       generic_update_time fs/inode.c:1946 [inline]
       inode_update_time fs/inode.c:1959 [inline]
       __file_update_time+0x21d/0x240 fs/inode.c:2147
       file_update_time+0x2d3/0x340 fs/inode.c:2178
       filemap_page_mkwrite+0x271/0x630 mm/filemap.c:3546
       do_page_mkwrite+0x16b/0x5c0 mm/memory.c:3009
       do_shared_fault mm/memory.c:4694 [inline]
       do_fault mm/memory.c:4762 [inline]
       handle_pte_fault mm/memory.c:5029 [inline]
       __handle_mm_fault mm/memory.c:5171 [inline]
       handle_mm_fault+0x1b10/0x3e60 mm/memory.c:5292
       do_user_addr_fault+0x51f/0xb10 arch/x86/mm/fault.c:1340
       handle_page_fault arch/x86/mm/fault.c:1431 [inline]
       exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1487
       asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608

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.0.219/4834:
 #0: ffff888027e99058 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
 #0: ffff888027e99058 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline]
 #0: ffff888027e99058 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382
 #1: ffff888078b6a558 (sb_pagefaults#2){.+.+}-{0:0}, at: do_page_mkwrite+0x16b/0x5c0 mm/memory.c:3009

stack backtrace:
CPU: 1 PID: 4834 Comm: syz.0.219 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
 reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
 reiserfs_dirty_inode+0xf0/0x240 fs/reiserfs/super.c:704
 __mark_inode_dirty+0x2eb/0xe90 fs/fs-writeback.c:2443
 generic_update_time fs/inode.c:1946 [inline]
 inode_update_time fs/inode.c:1959 [inline]
 __file_update_time+0x21d/0x240 fs/inode.c:2147
 file_update_time+0x2d3/0x340 fs/inode.c:2178
 filemap_page_mkwrite+0x271/0x630 mm/filemap.c:3546
 do_page_mkwrite+0x16b/0x5c0 mm/memory.c:3009
 do_shared_fault mm/memory.c:4694 [inline]
 do_fault mm/memory.c:4762 [inline]
 handle_pte_fault mm/memory.c:5029 [inline]
 __handle_mm_fault mm/memory.c:5171 [inline]
 handle_mm_fault+0x1b10/0x3e60 mm/memory.c:5292
 do_user_addr_fault+0x51f/0xb10 arch/x86/mm/fault.c:1340
 handle_page_fault arch/x86/mm/fault.c:1431 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1487
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7f9f0775736b
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:00007ffc06249b58 EFLAGS: 00010202
RAX: 0000200000000400 RBX: 0000000000000004 RCX: 0000000000737562
RDX: 0000000000000006 RSI: 0000000075622f2e RDI: 0000200000000400
RBP: 0000000000000000 R08: 0000001b2e120000 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000009 R12: 00007f9f079e5fac
R13: 00007f9f079e5fa0 R14: fffffffffffffffe R15: 0000000000000006
 </TASK>