Message-ID: <672dbfef.050a0220.69327.0001.GAE@google.com>
Date: Thu, 07 Nov 2024 23:38:23 -0800
From: syzbot <syzbot+d27edf9f96ae85939222@...kaller.appspotmail.com>
To: almaz.alexandrovich@...agon-software.com, linux-kernel@...r.kernel.org, 
	ntfs3@...ts.linux.dev, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [ntfs3?] possible deadlock in ntfs_look_for_free_space

Hello,

syzbot found the following issue on:

HEAD commit:    74741a050b79 Add linux-next specific files for 20241107
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13f15d87980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d3ef0574c9dc8b00
dashboard link: https://syzkaller.appspot.com/bug?extid=d27edf9f96ae85939222
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8993ea1d09da/disk-74741a05.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dab7bc3c6e88/vmlinux-74741a05.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fda543ad532f/bzImage-74741a05.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d27edf9f96ae85939222@...kaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.12.0-rc6-next-20241107-syzkaller #0 Not tainted
------------------------------------------------------
syz.1.532/8903 is trying to acquire lock:
ffff888060c52270 (&wnd->rw_lock){++++}-{4:4}, at: ntfs_look_for_free_space+0x100/0x690 fs/ntfs3/fsntfs.c:362

but task is already holding lock:
ffff888059c0efd8 (&ni->file.run_lock#2){++++}-{4:4}, at: ntfs_set_size+0x13d/0x200 fs/ntfs3/inode.c:852

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&ni->file.run_lock#2){++++}-{4:4}:
       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
       ntfs_dir_emit fs/ntfs3/dir.c:335 [inline]
       ntfs_read_hdr+0x700/0xb80 fs/ntfs3/dir.c:383
       ntfs_readdir+0x91f/0xf00 fs/ntfs3/dir.c:494
       iterate_dir+0x571/0x800 fs/readdir.c:108
       __do_sys_getdents64 fs/readdir.c:403 [inline]
       __se_sys_getdents64+0x1e2/0x4b0 fs/readdir.c:389
       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 (&wnd->rw_lock){++++}-{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_write_nested+0xa2/0x220 kernel/locking/rwsem.c:1693
       ntfs_look_for_free_space+0x100/0x690 fs/ntfs3/fsntfs.c:362
       attr_allocate_clusters+0x1d6/0x990 fs/ntfs3/attrib.c:159
       attr_set_size+0x2053/0x4300 fs/ntfs3/attrib.c:574
       ntfs_set_size+0x161/0x200 fs/ntfs3/inode.c:854
       ntfs_extend+0x1d1/0xad0 fs/ntfs3/file.c:409
       ntfs_setattr+0x2aa/0xb80 fs/ntfs3/file.c:826
       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

other info that might help us debug this:

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

4 locks held by syz.1.532/8903:
 #0: ffff888060c54420 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
 #1: ffff888059c0f1c0 (&sb->s_type->i_mutex_key#29){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:817 [inline]
 #1: ffff888059c0f1c0 (&sb->s_type->i_mutex_key#29){+.+.}-{4:4}, at: do_truncate+0x20c/0x310 fs/open.c:63
 #2: ffff888059c0ef28 (&ni->ni_lock#3/5){+.+.}-{4:4}, at: ni_lock fs/ntfs3/ntfs_fs.h:1110 [inline]
 #2: ffff888059c0ef28 (&ni->ni_lock#3/5){+.+.}-{4:4}, at: ntfs_set_size+0x12e/0x200 fs/ntfs3/inode.c:851
 #3: ffff888059c0efd8 (&ni->file.run_lock#2){++++}-{4:4}, at: ntfs_set_size+0x13d/0x200 fs/ntfs3/inode.c:852

stack backtrace:
CPU: 0 UID: 0 PID: 8903 Comm: syz.1.532 Not tainted 6.12.0-rc6-next-20241107-syzkaller #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+0x1397/0x2100 kernel/locking/lockdep.c:5226
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
 down_write_nested+0xa2/0x220 kernel/locking/rwsem.c:1693
 ntfs_look_for_free_space+0x100/0x690 fs/ntfs3/fsntfs.c:362
 attr_allocate_clusters+0x1d6/0x990 fs/ntfs3/attrib.c:159
 attr_set_size+0x2053/0x4300 fs/ntfs3/attrib.c:574
 ntfs_set_size+0x161/0x200 fs/ntfs3/inode.c:854
 ntfs_extend+0x1d1/0xad0 fs/ntfs3/file.c:409
 ntfs_setattr+0x2aa/0xb80 fs/ntfs3/file.c:826
 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
RIP: 0033:0x7f49bd97e719
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:00007f49be6ea038 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007f49bdb35f80 RCX: 00007f49bd97e719
RDX: 0000000000000000 RSI: 0000000000101000 RDI: 0000000020000080
RBP: 00007f49bd9f139e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f49bdb35f80 R15: 00007fffc9d8ce08
 </TASK>


---
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