syzbot


possible deadlock in run_unpack_ex

Status: upstream: reported on 2025/06/30 17:57
Reported-by: syzbot+84f81a699ba821308b7f@syzkaller.appspotmail.com
First crash: 10d, last: 17h39m
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in run_unpack_ex ntfs3 4 C done 6121 1d06h 245d 0/29 upstream: reported C repro on 2024/11/08 07:38

Sample crash report:
ntfs3: loop8: Different NTFS sector size (1024) and media sector size (512).
ntfs3: loop8: Mark volume as dirty due to NTFS errors
ntfs3: loop8: Failed to load $Extend (-22).
ntfs3: loop8: Failed to initialize $Extend.
======================================================
WARNING: possible circular locking dependency detected
6.6.97-syzkaller #0 Not tainted
------------------------------------------------------
syz.8.649/8818 is trying to acquire lock:
ffff88805def4b70 (&ni->file.run_lock#2){++++}-{3:3}, at: run_unpack_ex+0x7e6/0xba0 fs/ntfs3/run.c:1117

but task is already holding lock:
ffff88801d744270 (&wnd->rw_lock){++++}-{3:3}, at: run_unpack_ex+0x702/0xba0 fs/ntfs3/run.c:1098

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&wnd->rw_lock){++++}-{3:3}:
       down_write_nested+0x9e/0x1f0 kernel/locking/rwsem.c:1689
       ntfs_look_for_free_space+0xd4/0x600 fs/ntfs3/fsntfs.c:362
       attr_allocate_clusters+0x1c2/0x6d0 fs/ntfs3/attrib.c:159
       attr_set_size+0x14a0/0x2c60 fs/ntfs3/attrib.c:575
       ntfs_set_size+0x164/0x200 fs/ntfs3/inode.c:849
       ntfs_extend+0x157/0x4d0 fs/ntfs3/file.c:332
       ntfs_file_write_iter+0x3a7/0x700 fs/ntfs3/file.c:1115
       do_iter_readv_writev fs/read_write.c:-1 [inline]
       do_iter_write+0x79a/0xc70 fs/read_write.c:860
       iter_file_splice_write+0x66f/0xc50 fs/splice.c:736
       do_splice_from fs/splice.c:933 [inline]
       direct_splice_actor+0xe8/0x130 fs/splice.c:1142
       splice_direct_to_actor+0x2f0/0x870 fs/splice.c:1088
       do_splice_direct+0x1b7/0x2c0 fs/splice.c:1194
       do_sendfile+0x5dc/0xf70 fs/read_write.c:1254
       __do_sys_sendfile64 fs/read_write.c:1322 [inline]
       __se_sys_sendfile64+0x13f/0x190 fs/read_write.c:1308
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&ni->file.run_lock#2){++++}-{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+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
       lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
       down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520
       run_unpack_ex+0x7e6/0xba0 fs/ntfs3/run.c:1117
       ntfs_read_mft fs/ntfs3/inode.c:401 [inline]
       ntfs_iget5+0x22e3/0x3750 fs/ntfs3/inode.c:533
       dir_search_u+0x1e0/0x2b0 fs/ntfs3/dir.c:264
       ntfs_atomic_open+0x23b/0x520 fs/ntfs3/namei.c:412
       atomic_open fs/namei.c:3351 [inline]
       lookup_open fs/namei.c:3459 [inline]
       open_last_lookups fs/namei.c:3556 [inline]
       path_openat+0xf27/0x3190 fs/namei.c:3786
       do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
       do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
       do_sys_open fs/open.c:1434 [inline]
       __do_sys_open fs/open.c:1442 [inline]
       __se_sys_open fs/open.c:1438 [inline]
       __x64_sys_open+0x11f/0x140 fs/open.c:1438
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&wnd->rw_lock);
                               lock(&ni->file.run_lock#2);
                               lock(&wnd->rw_lock);
  rlock(&ni->file.run_lock#2);

 *** DEADLOCK ***

4 locks held by syz.8.649/8818:
 #0: ffff88803113e418 (sb_writers#18){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:403
 #1: ffff88805def6390 (&type->i_mutex_dir_key#11){++++}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
 #1: ffff88805def6390 (&type->i_mutex_dir_key#11){++++}-{3:3}, at: open_last_lookups fs/namei.c:3553 [inline]
 #1: ffff88805def6390 (&type->i_mutex_dir_key#11){++++}-{3:3}, at: path_openat+0x7c6/0x3190 fs/namei.c:3786
 #2: ffff88805def60e0 (&ni->ni_lock/6){+.+.}-{3:3}, at: ni_lock_dir fs/ntfs3/ntfs_fs.h:1125 [inline]
 #2: ffff88805def60e0 (&ni->ni_lock/6){+.+.}-{3:3}, at: ntfs_atomic_open+0x1ec/0x520 fs/ntfs3/namei.c:404
 #3: ffff88801d744270 (&wnd->rw_lock){++++}-{3:3}, at: run_unpack_ex+0x702/0xba0 fs/ntfs3/run.c:1098

stack backtrace:
CPU: 1 PID: 8818 Comm: syz.8.649 Not tainted 6.6.97-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 check_noncircular+0x2bd/0x3c0 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+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
 down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520
 run_unpack_ex+0x7e6/0xba0 fs/ntfs3/run.c:1117
 ntfs_read_mft fs/ntfs3/inode.c:401 [inline]
 ntfs_iget5+0x22e3/0x3750 fs/ntfs3/inode.c:533
 dir_search_u+0x1e0/0x2b0 fs/ntfs3/dir.c:264
 ntfs_atomic_open+0x23b/0x520 fs/ntfs3/namei.c:412
 atomic_open fs/namei.c:3351 [inline]
 lookup_open fs/namei.c:3459 [inline]
 open_last_lookups fs/namei.c:3556 [inline]
 path_openat+0xf27/0x3190 fs/namei.c:3786
 do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
 do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
 do_sys_open fs/open.c:1434 [inline]
 __do_sys_open fs/open.c:1442 [inline]
 __se_sys_open fs/open.c:1438 [inline]
 __x64_sys_open+0x11f/0x140 fs/open.c:1438
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f1f8bd8e929
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:00007f1f8cca6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f1f8bfb5fa0 RCX: 00007f1f8bd8e929
RDX: 0000000000000022 RSI: 0000000000064842 RDI: 0000200000000080
RBP: 00007f1f8be10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f1f8bfb5fa0 R15: 00007ffc07aa1b18
 </TASK>

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/10 23:52 linux-6.6.y 59a2de10b81a 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan possible deadlock in run_unpack_ex
2025/07/04 00:12 linux-6.6.y 3f5b4c104b7d 76ad128c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan possible deadlock in run_unpack_ex
2025/07/04 00:12 linux-6.6.y 3f5b4c104b7d 76ad128c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan possible deadlock in run_unpack_ex
2025/07/03 21:26 linux-6.6.y 3f5b4c104b7d 115ceea7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan possible deadlock in run_unpack_ex
2025/07/03 21:23 linux-6.6.y 3f5b4c104b7d 115ceea7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan possible deadlock in run_unpack_ex
2025/07/02 04:24 linux-6.6.y 3f5b4c104b7d bc80e4f0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan possible deadlock in run_unpack_ex
2025/07/02 04:24 linux-6.6.y 3f5b4c104b7d bc80e4f0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan possible deadlock in run_unpack_ex
2025/06/30 17:57 linux-6.6.y 3f5b4c104b7d 6e83b42d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan possible deadlock in run_unpack_ex
2025/06/30 17:56 linux-6.6.y 3f5b4c104b7d 6e83b42d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan possible deadlock in run_unpack_ex
* Struck through repros no longer work on HEAD.