syzbot


possible deadlock in ntfs_unlink_inode

Status: upstream: reported on 2024/08/23 03:34
Subsystems: ntfs3
[Documentation on labels]
Reported-by: syzbot+cccc70d683efa1c3f6a3@syzkaller.appspotmail.com
First crash: 94d, last: 1d23h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [ntfs3?] possible deadlock in ntfs_unlink_inode 0 (1) 2024/08/23 03:34

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.12.0-syzkaller-00171-g23acd177540d #0 Not tainted
------------------------------------------------------
syz-executor/9221 is trying to acquire lock:
ffff88805ab66078 (&ni->ni_lock#2/5){+.+.}-{3:3}, at: ni_lock fs/ntfs3/ntfs_fs.h:1109 [inline]
ffff88805ab66078 (&ni->ni_lock#2/5){+.+.}-{3:3}, at: ntfs_unlink_inode+0x324/0x7c0 fs/ntfs3/inode.c:1765

but task is already holding lock:
ffff88805ab61708 (&ni->ni_lock/6){+.+.}-{3:3}, at: ni_lock_dir fs/ntfs3/ntfs_fs.h:1114 [inline]
ffff88805ab61708 (&ni->ni_lock/6){+.+.}-{3:3}, at: ntfs_rmdir+0xb1/0xf0 fs/ntfs3/namei.c:222

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&ni->ni_lock/6){+.+.}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
       ni_lock_dir fs/ntfs3/ntfs_fs.h:1114 [inline]
       ntfs_unlink+0xb1/0xf0 fs/ntfs3/namei.c:177
       vfs_unlink+0x365/0x650 fs/namei.c:4510
       do_unlinkat+0x4ae/0x830 fs/namei.c:4574
       __do_sys_unlink fs/namei.c:4622 [inline]
       __se_sys_unlink fs/namei.c:4620 [inline]
       __x64_sys_unlink+0x47/0x50 fs/namei.c:4620
       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

-> #2 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
       down_write+0x99/0x220 kernel/locking/rwsem.c:1577
       inode_lock include/linux/fs.h:818 [inline]
       ntfs_file_mmap+0x5bc/0x850 fs/ntfs3/file.c:377
       call_mmap include/linux/fs.h:2183 [inline]
       mmap_file mm/internal.h:123 [inline]
       __mmap_region mm/mmap.c:1453 [inline]
       mmap_region+0x1a2a/0x23f0 mm/mmap.c:1603
       do_mmap+0x8f0/0x1000 mm/mmap.c:496
       vm_mmap_pgoff+0x1dd/0x3d0 mm/util.c:588
       ksys_mmap_pgoff+0x4eb/0x720 mm/mmap.c:542
       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

-> #1 (&mm->mmap_lock){++++}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
       __might_fault+0xc6/0x120 mm/memory.c:6716
       _inline_copy_to_user include/linux/uaccess.h:192 [inline]
       _copy_to_user+0x2c/0xb0 lib/usercopy.c:26
       copy_to_user include/linux/uaccess.h:225 [inline]
       ni_fiemap+0x57c/0x18c0 fs/ntfs3/frecord.c:2139
       ntfs_fiemap+0x132/0x180 fs/ntfs3/file.c:1352
       ioctl_fiemap fs/ioctl.c:220 [inline]
       do_vfs_ioctl+0x1bf8/0x2e40 fs/ioctl.c:841
       __do_sys_ioctl fs/ioctl.c:905 [inline]
       __se_sys_ioctl+0x81/0x170 fs/ioctl.c:893
       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 (&ni->ni_lock#2/5){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3161 [inline]
       check_prevs_add kernel/locking/lockdep.c:3280 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
       __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
       ni_lock fs/ntfs3/ntfs_fs.h:1109 [inline]
       ntfs_unlink_inode+0x324/0x7c0 fs/ntfs3/inode.c:1765
       ntfs_rmdir+0xbc/0xf0 fs/ntfs3/namei.c:224
       vfs_rmdir+0x3a3/0x510 fs/namei.c:4381
       do_rmdir+0x3b5/0x580 fs/namei.c:4440
       __do_sys_unlinkat fs/namei.c:4616 [inline]
       __se_sys_unlinkat fs/namei.c:4610 [inline]
       __x64_sys_unlinkat+0xde/0xf0 fs/namei.c:4610
       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:

Chain exists of:
  &ni->ni_lock#2/5 --> &sb->s_type->i_mutex_key#21 --> &ni->ni_lock/6

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ni->ni_lock/6);
                               lock(&sb->s_type->i_mutex_key#21);
                               lock(&ni->ni_lock/6);
  lock(&ni->ni_lock#2/5);

 *** DEADLOCK ***

4 locks held by syz-executor/9221:
 #0: ffff888071816420 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
 #1: ffff88805ab619a0 (&type->i_mutex_dir_key#8/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:853 [inline]
 #1: ffff88805ab619a0 (&type->i_mutex_dir_key#8/1){+.+.}-{3:3}, at: do_rmdir+0x263/0x580 fs/namei.c:4428
 #2: ffff88805ab66310 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:818 [inline]
 #2: ffff88805ab66310 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: vfs_rmdir+0x101/0x510 fs/namei.c:4370
 #3: ffff88805ab61708 (&ni->ni_lock/6){+.+.}-{3:3}, at: ni_lock_dir fs/ntfs3/ntfs_fs.h:1114 [inline]
 #3: ffff88805ab61708 (&ni->ni_lock/6){+.+.}-{3:3}, at: ntfs_rmdir+0xb1/0xf0 fs/ntfs3/namei.c:222

stack backtrace:
CPU: 1 UID: 0 PID: 9221 Comm: syz-executor Not tainted 6.12.0-syzkaller-00171-g23acd177540d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
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:2206
 check_prev_add kernel/locking/lockdep.c:3161 [inline]
 check_prevs_add kernel/locking/lockdep.c:3280 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
 ni_lock fs/ntfs3/ntfs_fs.h:1109 [inline]
 ntfs_unlink_inode+0x324/0x7c0 fs/ntfs3/inode.c:1765
 ntfs_rmdir+0xbc/0xf0 fs/ntfs3/namei.c:224
 vfs_rmdir+0x3a3/0x510 fs/namei.c:4381
 do_rmdir+0x3b5/0x580 fs/namei.c:4440
 __do_sys_unlinkat fs/namei.c:4616 [inline]
 __se_sys_unlinkat fs/namei.c:4610 [inline]
 __x64_sys_unlinkat+0xde/0xf0 fs/namei.c:4610
 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: 0033:0x7fbbad77dd37
Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 07 01 00 00 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:00007ffd1d1e55c8 EFLAGS: 00000207 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 00007fbbad77dd37
RDX: 0000000000000200 RSI: 00007ffd1d1e6770 RDI: 00000000ffffff9c
RBP: 00007fbbad7f15fc R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000207 R12: 00007ffd1d1e6770
R13: 00007fbbad7f15fc R14: 000000000006bef9 R15: 00007ffd1d1e8920
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/19 06:59 upstream 23acd177540d 571351cb .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in ntfs_unlink_inode
2024/08/19 03:23 upstream 47ac09b91bef dbc93b08 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in ntfs_unlink_inode
* Struck through repros no longer work on HEAD.