Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
Date:   Mon, 05 Dec 2022 02:59:46 -0800
In-Reply-To: <00000000000031714f05ee5b2257@google.com>
Message-ID: <000000000000e37a4005ef129563@google.com>
Subject: Re: [syzbot] possible deadlock in hfsplus_file_truncate
From:   syzbot <syzbot+6030b3b1b9bf70e538c4@syzkaller.appspotmail.com>
To:     linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        syzkaller-bugs@googlegroups.com, willy@infradead.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

syzbot has found a reproducer for the following issue on:

HEAD commit:    0ba09b173387 Revert "mm: align larger anonymous mappings o..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1517e983880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=2325e409a9a893e1
dashboard link: https://syzkaller.appspot.com/bug?extid=6030b3b1b9bf70e538c4
compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14b4d2cb880000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13d90fc3880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9758ec2c06f4/disk-0ba09b17.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/06781dbfd581/vmlinux-0ba09b17.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3d44a22d15fa/bzImage-0ba09b17.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/57266b2eb2c9/mount_0.gz
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/5f557bd13d34/mount_2.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6030b3b1b9bf70e538c4@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 1024
======================================================
WARNING: possible circular locking dependency detected
6.1.0-rc7-syzkaller-00211-g0ba09b173387 #0 Not tainted
------------------------------------------------------
syz-executor955/3635 is trying to acquire lock:
ffff8880279780b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_file_truncate+0x871/0xbb0 fs/hfsplus/extents.c:595

but task is already holding lock:
ffff8880189a3708 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_truncate+0x280/0xbb0 fs/hfsplus/extents.c:576

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}:
       lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
       __mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
       hfsplus_get_block+0x3a3/0x1560 fs/hfsplus/extents.c:260
       block_read_full_folio+0x3b3/0xfa0 fs/buffer.c:2271
       filemap_read_folio+0x187/0x7d0 mm/filemap.c:2407
       do_read_cache_folio+0x2d3/0x790 mm/filemap.c:3534
       do_read_cache_page mm/filemap.c:3576 [inline]
       read_cache_page+0x56/0x270 mm/filemap.c:3585
       read_mapping_page include/linux/pagemap.h:756 [inline]
       __hfs_bnode_create+0x4d5/0x7f0 fs/hfsplus/bnode.c:440
       hfsplus_bnode_find+0x23d/0xd80 fs/hfsplus/bnode.c:486
       hfsplus_brec_find+0x145/0x520 fs/hfsplus/bfind.c:183
       hfsplus_brec_read+0x27/0x100 fs/hfsplus/bfind.c:222
       hfsplus_find_cat+0x168/0x6d0 fs/hfsplus/catalog.c:202
       hfsplus_iget+0x402/0x630 fs/hfsplus/super.c:82
       hfsplus_fill_super+0xc6a/0x1b50 fs/hfsplus/super.c:503
       mount_bdev+0x26c/0x3a0 fs/super.c:1401
       legacy_get_tree+0xea/0x180 fs/fs_context.c:610
       vfs_get_tree+0x88/0x270 fs/super.c:1531
       do_new_mount+0x289/0xad0 fs/namespace.c:3040
       do_mount fs/namespace.c:3383 [inline]
       __do_sys_mount fs/namespace.c:3591 [inline]
       __se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3568
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&tree->tree_lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3097 [inline]
       check_prevs_add kernel/locking/lockdep.c:3216 [inline]
       validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
       __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
       lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
       __mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
       hfsplus_file_truncate+0x871/0xbb0 fs/hfsplus/extents.c:595
       hfsplus_delete_inode+0x16d/0x210
       hfsplus_unlink+0x4e2/0x7d0 fs/hfsplus/dir.c:405
       hfsplus_rename+0xc3/0x1b0 fs/hfsplus/dir.c:547
       vfs_rename+0xd53/0x1130 fs/namei.c:4779
       do_renameat2+0xb53/0x1370 fs/namei.c:4930
       __do_sys_rename fs/namei.c:4976 [inline]
       __se_sys_rename fs/namei.c:4974 [inline]
       __x64_sys_rename+0x82/0x90 fs/namei.c:4974
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&HFSPLUS_I(inode)->extents_lock);
                               lock(&tree->tree_lock);
                               lock(&HFSPLUS_I(inode)->extents_lock);
  lock(&tree->tree_lock);

 *** DEADLOCK ***

6 locks held by syz-executor955/3635:
 #0: ffff888075a6c460 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:393
 #1: ffff8880189a2b80 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: lock_rename+0x182/0x1a0
 #2: ffff8880189a3240 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
 #2: ffff8880189a3240 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: lock_two_nondirectories+0xdd/0x130 fs/inode.c:1121
 #3: ffff8880189a3900 (&sb->s_type->i_mutex_key#15/4){+.+.}-{3:3}, at: vfs_rename+0x80a/0x1130 fs/namei.c:4749
 #4: ffff888027abb198 (&sbi->vh_mutex){+.+.}-{3:3}, at: hfsplus_unlink+0x135/0x7d0 fs/hfsplus/dir.c:370
 #5: ffff8880189a3708 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_truncate+0x280/0xbb0 fs/hfsplus/extents.c:576

stack backtrace:
CPU: 1 PID: 3635 Comm: syz-executor955 Not tainted 6.1.0-rc7-syzkaller-00211-g0ba09b173387 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
 check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2177
 check_prev_add kernel/locking/lockdep.c:3097 [inline]
 check_prevs_add kernel/locking/lockdep.c:3216 [inline]
 validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
 __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
 lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
 __mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
 hfsplus_file_truncate+0x871/0xbb0 fs/hfsplus/extents.c:595
 hfsplus_delete_inode+0x16d/0x210
 hfsplus_unlink+0x4e2/0x7d0 fs/hfsplus/dir.c:405
 hfsplus_rename+0xc3/0x1b0 fs/hfsplus/dir.c:547
 vfs_rename+0xd53/0x1130 fs/namei.c:4779
 do_renameat2+0xb53/0x1370 fs/namei.c:4930
 __do_sys_rename fs/namei.c:4976 [inline]
 __se_sys_rename fs/namei.c:4974 [inline]
 __x64_sys_rename+0x82/0x90 fs/namei.c:4974
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f462a64f3f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f462a5da2f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f462a64f3f9
RDX: 0000000000000031 RSI: 00000000200001c0 RDI: 0000000020000180
RBP: 00007f462a6d4798 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000005fb R11: 0000000000000246 R12: 00007f462a6d4790
R13: 736f706d6f636564 R14: 0030656c69662f2e R15: 0073756c70736668
 </TASK>