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From: syzbot <syzbot+731b27ee9413ba859499@syzkaller.appspotmail.com>
To: almaz.alexandrovich@paragon-software.com,
	linux-kernel@vger.kernel.org,  ntfs3@lists.linux.dev,
	syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [ntfs3?] possible deadlock in run_unpack_ex
Date: Thu, 19 Dec 2024 18:51:26 -0800	[thread overview]
Message-ID: <6764dbae.050a0220.1bfc9e.0003.GAE@google.com> (raw)
In-Reply-To: <672dbfef.050a0220.69327.0000.GAE@google.com>

syzbot has found a reproducer for the following issue on:

HEAD commit:    baaa2567a712 Merge tag 'mmc-v6.13-rc2' of git://git.kernel..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=155d9f44580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1234f097ee657d8b
dashboard link: https://syzkaller.appspot.com/bug?extid=731b27ee9413ba859499
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11660fe8580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12ce62df980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/816d068f9171/disk-baaa2567.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9b40d3a7d8cc/vmlinux-baaa2567.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e9af7e09d18f/bzImage-baaa2567.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/9fd4a2bb86ce/mount_0.gz
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/87a127155fbe/mount_2.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+731b27ee9413ba859499@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc3-syzkaller-00082-gbaaa2567a712 #0 Not tainted
------------------------------------------------------
syz-executor336/5955 is trying to acquire lock:
ffff8880772ed9d0 (&ni->file.run_lock#2){++++}-{4:4}, at: run_unpack_ex+0x55e/0x9e0 fs/ntfs3/run.c:1119

but task is already holding lock:
ffff88807ffd4270 (&wnd->rw_lock){++++}-{4:4}, at: run_unpack_ex+0x47a/0x9e0 fs/ntfs3/run.c:1100

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&wnd->rw_lock){++++}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       down_write_nested+0xa2/0x220 kernel/locking/rwsem.c:1693
       mark_as_free_ex+0x3e/0x390 fs/ntfs3/fsntfs.c:2484
       run_deallocate_ex+0x244/0x5f0 fs/ntfs3/attrib.c:122
       attr_set_size+0x168d/0x4300 fs/ntfs3/attrib.c:753
       ntfs_truncate fs/ntfs3/file.c:506 [inline]
       ntfs_setattr+0x7a4/0xb80 fs/ntfs3/file.c:824
       notify_change+0xbca/0xe90 fs/attr.c:552
       do_truncate+0x220/0x310 fs/open.c:65
       vfs_truncate+0x2e1/0x3b0 fs/open.c:111
       do_sys_truncate+0xdb/0x190 fs/open.c:134
       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->file.run_lock#2){++++}-{4:4}:
       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+0x1397/0x2100 kernel/locking/lockdep.c:5226
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524
       run_unpack_ex+0x55e/0x9e0 fs/ntfs3/run.c:1119
       ntfs_read_mft fs/ntfs3/inode.c:401 [inline]
       ntfs_iget5+0x1f9a/0x37b0 fs/ntfs3/inode.c:537
       dir_search_u+0x2fe/0x3a0 fs/ntfs3/dir.c:264
       ntfs_lookup+0x106/0x1f0 fs/ntfs3/namei.c:85
       __lookup_slow+0x28c/0x3f0 fs/namei.c:1791
       lookup_slow+0x53/0x70 fs/namei.c:1808
       walk_component+0x2e1/0x410 fs/namei.c:2112
       lookup_last fs/namei.c:2610 [inline]
       path_lookupat+0x16f/0x450 fs/namei.c:2634
       filename_lookup+0x2a3/0x670 fs/namei.c:2663
       user_path_at+0x3a/0x60 fs/namei.c:3070
       do_mount fs/namespace.c:3844 [inline]
       __do_sys_mount fs/namespace.c:4057 [inline]
       __se_sys_mount+0x297/0x3c0 fs/namespace.c:4034
       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(&wnd->rw_lock);
                               lock(&ni->file.run_lock#2);
                               lock(&wnd->rw_lock);
  rlock(&ni->file.run_lock#2);

 *** DEADLOCK ***

3 locks held by syz-executor336/5955:
 #0: ffff8880703e5bb8 (&type->i_mutex_dir_key#8){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:828 [inline]
 #0: ffff8880703e5bb8 (&type->i_mutex_dir_key#8){++++}-{4:4}, at: lookup_slow+0x45/0x70 fs/namei.c:1807
 #1: ffff8880703e5920 (&ni->ni_lock#3/6){+.+.}-{4:4}, at: ni_lock_dir fs/ntfs3/ntfs_fs.h:1115 [inline]
 #1: ffff8880703e5920 (&ni->ni_lock#3/6){+.+.}-{4:4}, at: ntfs_lookup+0xf9/0x1f0 fs/ntfs3/namei.c:84
 #2: ffff88807ffd4270 (&wnd->rw_lock){++++}-{4:4}, at: run_unpack_ex+0x47a/0x9e0 fs/ntfs3/run.c:1100

stack backtrace:
CPU: 1 UID: 0 PID: 5955 Comm: syz-executor336 Not tainted 6.13.0-rc3-syzkaller-00082-gbaaa2567a712 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
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+0x1397/0x2100 kernel/locking/lockdep.c:5226
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
 down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524
 run_unpack_ex+0x55e/0x9e0 fs/ntfs3/run.c:1119
 ntfs_read_mft fs/ntfs3/inode.c:401 [inline]
 ntfs_iget5+0x1f9a/0x37b0 fs/ntfs3/inode.c:537
 dir_search_u+0x2fe/0x3a0 fs/ntfs3/dir.c:264
 ntfs_lookup+0x106/0x1f0 fs/ntfs3/namei.c:85
 __lookup_slow+0x28c/0x3f0 fs/namei.c:1791
 lookup_slow+0x53/0x70 fs/namei.c:1808
 walk_component+0x2e1/0x410 fs/namei.c:2112
 lookup_last fs/namei.c:2610 [inline]
 path_lookupat+0x16f/0x450 fs/namei.c:2634
 filename_lookup+0x2a3/0x670 fs/namei.c:2663
 user_path_at+0x3a/0x60 fs/namei.c:3070
 do_mount fs/namespace.c:3844 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount+0x297/0x3c0 fs/namespace.c:4034
 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: 0033:0x7febe4f8bed9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 19 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd61a52908 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007febe4f8bed9
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000000
RBP: 00007ffd61a5292c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000021 R11: 0000000000000246 R12: 00007ffd61a52980
R13: 00007ffd61a52940 R14: 0000000000014b5d R15: 0000000000000014
 </TASK>


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

  reply	other threads:[~2024-12-20  2:51 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-08  7:38 [syzbot] [ntfs3?] possible deadlock in run_unpack_ex syzbot
2024-12-20  2:51 ` syzbot [this message]
2024-12-20 22:26 ` syzbot

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