syzbot


possible deadlock in ntfs_file_write_iter

Status: upstream: reported on 2024/06/15 08:45
Subsystems: ntfs3
[Documentation on labels]
Reported-by: syzbot+d7452fc408a961bcc6ec@syzkaller.appspotmail.com
First crash: 37d, last: 23d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [ntfs3?] possible deadlock in ntfs_file_write_iter 0 (1) 2024/06/15 08:45

Sample crash report:
ntfs3: loop1: Different NTFS sector size (4096) and media sector size (512).
ntfs3: loop1: Failed to initialize $Extend/$Reparse.
======================================================
WARNING: possible circular locking dependency detected
6.10.0-rc5-next-20240624-syzkaller #0 Not tainted
------------------------------------------------------
syz.1.2791/13697 is trying to acquire lock:
ffff88807d37c418 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:153

but task is already holding lock:
ffff888048a68398 (&sb->s_type->i_mutex_key#29){+.+.}-{3:3}, at: inode_trylock include/linux/fs.h:819 [inline]
ffff888048a68398 (&sb->s_type->i_mutex_key#29){+.+.}-{3:3}, at: ntfs_file_write_iter+0x25a/0x770 fs/ntfs3/file.c:1099

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&sb->s_type->i_mutex_key#29){+.+.}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5816
       down_write+0x3a/0x50 kernel/locking/rwsem.c:1579
       inode_lock include/linux/fs.h:799 [inline]
       ntfs_file_mmap+0x5d8/0x860 fs/ntfs3/file.c:302
       call_mmap include/linux/fs.h:2129 [inline]
       mmap_region+0xe8f/0x2090 mm/mmap.c:2927
       do_mmap+0x8ad/0xfa0 mm/mmap.c:1438
       vm_mmap_pgoff+0x1dd/0x3d0 mm/util.c:576
       ksys_mmap_pgoff+0x4f1/0x720 mm/mmap.c:1484
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&mm->mmap_lock){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3158 [inline]
       check_prevs_add kernel/locking/lockdep.c:3277 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
       __lock_acquire+0x1359/0x2000 kernel/locking/lockdep.c:5193
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5816
       down_read_killable+0xca/0xd30 kernel/locking/rwsem.c:1549
       mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:153
       get_mmap_lock_carefully mm/memory.c:5866 [inline]
       lock_mm_and_find_vma+0x29c/0x2f0 mm/memory.c:5917
       do_user_addr_fault arch/x86/mm/fault.c:1361 [inline]
       handle_page_fault arch/x86/mm/fault.c:1481 [inline]
       exc_page_fault+0x1bf/0x8c0 arch/x86/mm/fault.c:1539
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
       fault_in_readable+0x108/0x2b0 mm/gup.c:2333
       fault_in_iov_iter_readable+0x229/0x280 lib/iov_iter.c:94
       generic_perform_write+0x492/0x640 mm/filemap.c:4006
       ntfs_file_write_iter+0x68f/0x770 fs/ntfs3/file.c:1126
       new_sync_write fs/read_write.c:497 [inline]
       vfs_write+0xa72/0xc90 fs/read_write.c:590
       ksys_write+0x1a0/0x2c0 fs/read_write.c:643
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sb->s_type->i_mutex_key#29);
                               lock(&mm->mmap_lock);
                               lock(&sb->s_type->i_mutex_key#29);
  rlock(&mm->mmap_lock);

 *** DEADLOCK ***

3 locks held by syz.1.2791/13697:
 #0: ffff8880746099c8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x24e/0x310 fs/file.c:1191
 #1: ffff8880470a0420 (sb_writers#22){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2876 [inline]
 #1: ffff8880470a0420 (sb_writers#22){.+.+}-{0:0}, at: vfs_write+0x227/0xc90 fs/read_write.c:586
 #2: ffff888048a68398 (&sb->s_type->i_mutex_key#29){+.+.}-{3:3}, at: inode_trylock include/linux/fs.h:819 [inline]
 #2: ffff888048a68398 (&sb->s_type->i_mutex_key#29){+.+.}-{3:3}, at: ntfs_file_write_iter+0x25a/0x770 fs/ntfs3/file.c:1099

stack backtrace:
CPU: 0 UID: 0 PID: 13697 Comm: syz.1.2791 Not tainted 6.10.0-rc5-next-20240624-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2203
 check_prev_add kernel/locking/lockdep.c:3158 [inline]
 check_prevs_add kernel/locking/lockdep.c:3277 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
 __lock_acquire+0x1359/0x2000 kernel/locking/lockdep.c:5193
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5816
 down_read_killable+0xca/0xd30 kernel/locking/rwsem.c:1549
 mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:153
 get_mmap_lock_carefully mm/memory.c:5866 [inline]
 lock_mm_and_find_vma+0x29c/0x2f0 mm/memory.c:5917
 do_user_addr_fault arch/x86/mm/fault.c:1361 [inline]
 handle_page_fault arch/x86/mm/fault.c:1481 [inline]
 exc_page_fault+0x1bf/0x8c0 arch/x86/mm/fault.c:1539
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:fault_in_readable+0x108/0x2b0 mm/gup.c:2334
Code: 00 00 00 0f 01 cb 0f ae e8 48 89 de 48 81 e6 ff 0f 00 00 31 ff e8 78 b4 b4 ff 48 89 d8 48 25 ff 0f 00 00 4c 89 74 24 18 74 30 <8a> 1b e8 81 af b4 ff 43 0f b6 04 2f 84 c0 0f 85 4d 01 00 00 88 5c
RSP: 0018:ffffc9000446f9e0 EFLAGS: 00050206
RAX: 00000000000008c0 RBX: 00000000200008c0 RCX: ffff88806f785a00
RDX: ffffc900094e1000 RSI: 00000000000008c0 RDI: 0000000000000000
RBP: ffffc9000446fa98 R08: ffffffff81dec328 R09: ffffffff84acea89
R10: 0000000000000002 R11: ffff88806f785a00 R12: 0000000000001000
R13: dffffc0000000000 R14: 1ffff9200088df40 R15: 1ffff9200088df44
 fault_in_iov_iter_readable+0x229/0x280 lib/iov_iter.c:94
 generic_perform_write+0x492/0x640 mm/filemap.c:4006
 ntfs_file_write_iter+0x68f/0x770 fs/ntfs3/file.c:1126
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xa72/0xc90 fs/read_write.c:590
 ksys_write+0x1a0/0x2c0 fs/read_write.c:643
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3e02f75ae9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3e03dbe048 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f3e03103fa0 RCX: 00007f3e02f75ae9
RDX: 000000000000fecc RSI: 00000000200008c0 RDI: 0000000000000004
RBP: 00007f3e02ff6746 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f3e03103fa0 R15: 00007ffc8b434c08
 </TASK>
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	00 0f                	add    %cl,(%rdi)
   4:	01 cb                	add    %ecx,%ebx
   6:	0f ae e8             	lfence
   9:	48 89 de             	mov    %rbx,%rsi
   c:	48 81 e6 ff 0f 00 00 	and    $0xfff,%rsi
  13:	31 ff                	xor    %edi,%edi
  15:	e8 78 b4 b4 ff       	call   0xffb4b492
  1a:	48 89 d8             	mov    %rbx,%rax
  1d:	48 25 ff 0f 00 00    	and    $0xfff,%rax
  23:	4c 89 74 24 18       	mov    %r14,0x18(%rsp)
  28:	74 30                	je     0x5a
* 2a:	8a 1b                	mov    (%rbx),%bl <-- trapping instruction
  2c:	e8 81 af b4 ff       	call   0xffb4afb2
  31:	43 0f b6 04 2f       	movzbl (%r15,%r13,1),%eax
  36:	84 c0                	test   %al,%al
  38:	0f 85 4d 01 00 00    	jne    0x18b
  3e:	88                   	.byte 0x88
  3f:	5c                   	pop    %rsp

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/25 16:17 linux-next 62c97045b8f7 da0bd5ca .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root possible deadlock in ntfs_file_write_iter
2024/06/17 02:16 linux-next a957267fa7e9 f429ab00 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root possible deadlock in ntfs_file_write_iter
2024/06/11 08:43 linux-next a957267fa7e9 048c640a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root possible deadlock in ntfs_file_write_iter
* Struck through repros no longer work on HEAD.