Re: [syzbot] possible deadlock in hfsplus_file_truncate

[Chao Yu <chao@kernel.org>]

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/chao/linux.git misc

On 2022/12/5 18:59, syzbot wrote:
> 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>
>