syzbot

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.1.1013/10309 is trying to acquire lock:
ffff888026a15090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x79/0xd0 fs/reiserfs/lock.c:27

but task is already holding lock:
ffff88806576e510 (sb_pagefaults#4){.+.+}-{0:0}, at: do_page_mkwrite+0x153/0x3e0 mm/memory.c:2951

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (sb_pagefaults#4){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1633 [inline]
       sb_start_pagefault include/linux/fs.h:1737 [inline]
       filemap_page_mkwrite+0x161/0x650 mm/filemap.c:3690
       do_page_mkwrite+0x153/0x3e0 mm/memory.c:2951
       wp_page_shared mm/memory.c:3311 [inline]
       do_wp_page+0xdff/0x35f0 mm/memory.c:3396
       handle_pte_fault mm/memory.c:5063 [inline]
       __handle_mm_fault mm/memory.c:5188 [inline]
       handle_mm_fault+0x135d/0x4c00 mm/memory.c:5353
       do_user_addr_fault+0x730/0x12c0 arch/x86/mm/fault.c:1371
       handle_page_fault arch/x86/mm/fault.c:1463 [inline]
       exc_page_fault+0x64/0x100 arch/x86/mm/fault.c:1516
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608

-> #1 (&mm->mmap_lock){++++}-{3:3}:
       __might_fault+0xc6/0x120 mm/memory.c:5968
       reiserfs_ioctl+0x143/0x2d0 fs/reiserfs/ioctl.c:96
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:871 [inline]
       __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x55/0xa0 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:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x2df1/0x7d40 kernel/locking/lockdep.c:5137
       lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x136/0xcc0 kernel/locking/mutex.c:747
       reiserfs_write_lock+0x79/0xd0 fs/reiserfs/lock.c:27
       reiserfs_dirty_inode+0x111/0x270 fs/reiserfs/super.c:704
       __mark_inode_dirty+0x2cc/0xc90 fs/fs-writeback.c:2471
       generic_update_time fs/inode.c:1981 [inline]
       inode_update_time fs/inode.c:1994 [inline]
       __file_update_time fs/inode.c:2180 [inline]
       file_update_time+0x187/0x1a0 fs/inode.c:2210
       filemap_page_mkwrite+0x28b/0x650 mm/filemap.c:3691
       do_page_mkwrite+0x153/0x3e0 mm/memory.c:2951
       wp_page_shared mm/memory.c:3311 [inline]
       do_wp_page+0xdff/0x35f0 mm/memory.c:3396
       handle_pte_fault mm/memory.c:5063 [inline]
       __handle_mm_fault mm/memory.c:5188 [inline]
       handle_mm_fault+0x135d/0x4c00 mm/memory.c:5353
       do_user_addr_fault+0x730/0x12c0 arch/x86/mm/fault.c:1371
       handle_page_fault arch/x86/mm/fault.c:1463 [inline]
       exc_page_fault+0x64/0x100 arch/x86/mm/fault.c:1516
       asm_exc_page_fault+0x26/0x30 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#4

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(sb_pagefaults#4);
                               lock(&mm->mmap_lock);
                               lock(sb_pagefaults#4);
  lock(&sbi->lock);

 *** DEADLOCK ***

2 locks held by syz.1.1013/10309:
 #0: ffff88802ea49e20 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline]
 #0: ffff88802ea49e20 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline]
 #0: ffff88802ea49e20 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440
 #1: ffff88806576e510 (sb_pagefaults#4){.+.+}-{0:0}, at: do_page_mkwrite+0x153/0x3e0 mm/memory.c:2951

stack backtrace:
CPU: 0 PID: 10309 Comm: syz.1.1013 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 check_noncircular+0x2fc/0x400 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3869 [inline]
 __lock_acquire+0x2df1/0x7d40 kernel/locking/lockdep.c:5137
 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x136/0xcc0 kernel/locking/mutex.c:747
 reiserfs_write_lock+0x79/0xd0 fs/reiserfs/lock.c:27
 reiserfs_dirty_inode+0x111/0x270 fs/reiserfs/super.c:704
 __mark_inode_dirty+0x2cc/0xc90 fs/fs-writeback.c:2471
 generic_update_time fs/inode.c:1981 [inline]
 inode_update_time fs/inode.c:1994 [inline]
 __file_update_time fs/inode.c:2180 [inline]
 file_update_time+0x187/0x1a0 fs/inode.c:2210
 filemap_page_mkwrite+0x28b/0x650 mm/filemap.c:3691
 do_page_mkwrite+0x153/0x3e0 mm/memory.c:2951
 wp_page_shared mm/memory.c:3311 [inline]
 do_wp_page+0xdff/0x35f0 mm/memory.c:3396
 handle_pte_fault mm/memory.c:5063 [inline]
 __handle_mm_fault mm/memory.c:5188 [inline]
 handle_mm_fault+0x135d/0x4c00 mm/memory.c:5353
 do_user_addr_fault+0x730/0x12c0 arch/x86/mm/fault.c:1371
 handle_page_fault arch/x86/mm/fault.c:1463 [inline]
 exc_page_fault+0x64/0x100 arch/x86/mm/fault.c:1516
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7fe998b6b6d8
Code: fc 89 37 c3 c5 fa 6f 06 c5 fa 6f 4c 16 f0 c5 fa 7f 07 c5 fa 7f 4c 17 f0 c3 66 0f 1f 84 00 00 00 00 00 48 8b 4c 16 f8 48 8b 36 <48> 89 37 48 89 4c 17 f8 c3 c5 fe 6f 54 16 e0 c5 fe 6f 5c 16 c0 c5
RSP: 002b:00007ffe2d8da978 EFLAGS: 00010246
RAX: 0000200000000040 RBX: 0000000000000004 RCX: 0031656c69662f2e
RDX: 0000000000000008 RSI: 0031656c69662f2e RDI: 0000200000000040
RBP: fffffffffffffffe R08: 0000001b2c420000 R09: 0000000000000001
R10: 7ffffffffffffff7 R11: 0000000000000009 R12: 00007ffe2d8daaa0
R13: 00007fe998e1609c R14: 00000000000699b5 R15: 00007fe998e16090
 </TASK>