syzbot


possible deadlock in ntfs_unlink

Status: upstream: reported on 2024/08/21 06:45
Subsystems: ntfs3
[Documentation on labels]
Reported-by: syzbot+12f3574df80036f0f9ca@syzkaller.appspotmail.com
First crash: 96d, last: 20d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [ntfs3?] possible deadlock in ntfs_unlink 0 (1) 2024/08/21 06:45

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.12.0-rc5-syzkaller-00181-g6c52d4da1c74 #0 Not tainted
------------------------------------------------------
syz-executor/7142 is trying to acquire lock:
ffff88805b69e7d0 (&ni->ni_lock#3/6){+.+.}-{3:3}, at: ni_lock_dir fs/ntfs3/ntfs_fs.h:1114 [inline]
ffff88805b69e7d0 (&ni->ni_lock#3/6){+.+.}-{3:3}, at: ntfs_unlink+0xb1/0xf0 fs/ntfs3/namei.c:177

but task is already holding lock:
ffff88805b6fbe58 (&sb->s_type->i_mutex_key#32){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline]
ffff88805b6fbe58 (&sb->s_type->i_mutex_key#32){+.+.}-{3:3}, at: vfs_unlink+0xe4/0x650 fs/namei.c:4458

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&sb->s_type->i_mutex_key#32){+.+.}-{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:815 [inline]
       ntfs_file_mmap+0x5bc/0x850 fs/ntfs3/file.c:377
       call_mmap include/linux/fs.h:2172 [inline]
       mmap_region+0x1689/0x2940 mm/mmap.c:1449
       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

-> #2 (&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

-> #1 (&ni->ni_lock/5){+.+.}-{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 fs/ntfs3/ntfs_fs.h:1109 [inline]
       ntfs_rename+0x74a/0xd10 fs/ntfs3/namei.c:312
       vfs_rename+0xbdb/0xf00 fs/namei.c:5013
       do_renameat2+0xd94/0x13f0 fs/namei.c:5170
       __do_sys_renameat2 fs/namei.c:5204 [inline]
       __se_sys_renameat2 fs/namei.c:5201 [inline]
       __x64_sys_renameat2+0xce/0xe0 fs/namei.c:5201
       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#3/6){+.+.}-{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_dir fs/ntfs3/ntfs_fs.h:1114 [inline]
       ntfs_unlink+0xb1/0xf0 fs/ntfs3/namei.c:177
       vfs_unlink+0x365/0x650 fs/namei.c:4469
       do_unlinkat+0x4ae/0x830 fs/namei.c:4533
       __do_sys_unlink fs/namei.c:4581 [inline]
       __se_sys_unlink fs/namei.c:4579 [inline]
       __x64_sys_unlink+0x47/0x50 fs/namei.c:4579
       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#3/6 --> &mm->mmap_lock --> &sb->s_type->i_mutex_key#32

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sb->s_type->i_mutex_key#32);
                               lock(&mm->mmap_lock);
                               lock(&sb->s_type->i_mutex_key#32);
  lock(&ni->ni_lock#3/6);

 *** DEADLOCK ***

3 locks held by syz-executor/7142:
 #0: ffff8880122e6420 (sb_writers#20){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
 #1: ffff88805b69ea68 (&type->i_mutex_dir_key#15/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:850 [inline]
 #1: ffff88805b69ea68 (&type->i_mutex_dir_key#15/1){+.+.}-{3:3}, at: do_unlinkat+0x26a/0x830 fs/namei.c:4520
 #2: ffff88805b6fbe58 (&sb->s_type->i_mutex_key#32){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline]
 #2: ffff88805b6fbe58 (&sb->s_type->i_mutex_key#32){+.+.}-{3:3}, at: vfs_unlink+0xe4/0x650 fs/namei.c:4458

stack backtrace:
CPU: 0 UID: 0 PID: 7142 Comm: syz-executor Not tainted 6.12.0-rc5-syzkaller-00181-g6c52d4da1c74 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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_dir fs/ntfs3/ntfs_fs.h:1114 [inline]
 ntfs_unlink+0xb1/0xf0 fs/ntfs3/namei.c:177
 vfs_unlink+0x365/0x650 fs/namei.c:4469
 do_unlinkat+0x4ae/0x830 fs/namei.c:4533
 __do_sys_unlink fs/namei.c:4581 [inline]
 __se_sys_unlink fs/namei.c:4579 [inline]
 __x64_sys_unlink+0x47/0x50 fs/namei.c:4579
 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: 0033:0x7fb67557dcc7
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 57 00 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:00007ffc533d4498 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb67557dcc7
RDX: 00007ffc533d44c0 RSI: 00007ffc533d4550 RDI: 00007ffc533d4550
RBP: 00007ffc533d4550 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffc533d5640
R13: 00007fb6755f11cc R14: 000000000002d527 R15: 00007ffc533d6700
 </TASK>
ocfs2: Unmounting device (7,7) on (node local)

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/01 04:39 upstream 6c52d4da1c74 96eb609f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in ntfs_unlink
2024/08/17 06:39 upstream 85652baa895b dbc93b08 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in ntfs_unlink
* Struck through repros no longer work on HEAD.