Date: Mon, 01 Jan 2024 21:11:18 -0800
From: syzbot <syzbot+41a88b825a315aac2254@...kaller.appspotmail.com>
To: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [hfs?] possible deadlock in hfs_extend_file (2)

syzbot has found a reproducer for the following issue on:

HEAD commit:    610a9b8f49fb Linux 6.7-rc8
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16d7c48de80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=247b5a935d307ee5
dashboard link: https://syzkaller.appspot.com/bug?extid=41a88b825a315aac2254
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1552fe19e80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1419bcade80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e174ec82158f/disk-610a9b8f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4bed5e1c1c26/vmlinux-610a9b8f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4fd13b65ecb5/bzImage-610a9b8f.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/19a994dad52e/mount_0.gz
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/8c8468d1fd79/mount_1.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+41a88b825a315aac2254@...kaller.appspotmail.com

loop0: detected capacity change from 0 to 64
============================================
WARNING: possible recursive locking detected
6.7.0-rc8-syzkaller #0 Not tainted
--------------------------------------------
syz-executor279/5059 is trying to acquire lock:
ffff888079c100f8 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}, at: hfs_extend_file+0xa2/0xb10 fs/hfs/extent.c:397

but task is already holding lock:
ffff888079c10778 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}, at: hfs_extend_file+0xa2/0xb10 fs/hfs/extent.c:397

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&HFS_I(tree->inode)->extents_lock);
  lock(&HFS_I(tree->inode)->extents_lock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

5 locks held by syz-executor279/5059:
 #0: ffff88807a160418 (sb_writers#9){.+.+}-{0:0}, at: open_last_lookups fs/namei.c:3535 [inline]
 #0: ffff88807a160418 (sb_writers#9){.+.+}-{0:0}, at: path_openat+0x19f6/0x2c50 fs/namei.c:3776
 #1: ffff888079c10fa8 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:802 [inline]
 #1: ffff888079c10fa8 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: open_last_lookups fs/namei.c:3543 [inline]
 #1: ffff888079c10fa8 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: path_openat+0x8bd/0x2c50 fs/namei.c:3776
 #2: ffff88807a1640b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfs_find_init+0x1b6/0x220 fs/hfs/bfind.c:30
 #3: ffff888079c10778 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}, at: hfs_extend_file+0xa2/0xb10 fs/hfs/extent.c:397
 #4: ffff88807a1620b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x17f/0x220 fs/hfs/bfind.c:33

stack backtrace:
CPU: 0 PID: 5059 Comm: syz-executor279 Not tainted 6.7.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 check_deadlock kernel/locking/lockdep.c:3062 [inline]
 validate_chain kernel/locking/lockdep.c:3856 [inline]
 __lock_acquire+0x20f8/0x3b20 kernel/locking/lockdep.c:5137
 lock_acquire kernel/locking/lockdep.c:5754 [inline]
 lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5719
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x175/0x9d0 kernel/locking/mutex.c:747
 hfs_extend_file+0xa2/0xb10 fs/hfs/extent.c:397
 hfs_bmap_reserve+0x29c/0x370 fs/hfs/btree.c:234
 __hfs_ext_write_extent+0x3cb/0x520 fs/hfs/extent.c:121
 __hfs_ext_cache_extent fs/hfs/extent.c:174 [inline]
 hfs_ext_read_extent+0x805/0x9d0 fs/hfs/extent.c:202
 hfs_extend_file+0x4e0/0xb10 fs/hfs/extent.c:401
 hfs_bmap_reserve+0x29c/0x370 fs/hfs/btree.c:234
 hfs_cat_create+0x227/0x810 fs/hfs/catalog.c:104
 hfs_create+0x67/0xe0 fs/hfs/dir.c:202
 lookup_open.isra.0+0x1095/0x13b0 fs/namei.c:3477
 open_last_lookups fs/namei.c:3546 [inline]
 path_openat+0x922/0x2c50 fs/namei.c:3776
 do_filp_open+0x1de/0x430 fs/namei.c:3809
 do_sys_openat2+0x176/0x1e0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0x175/0x210 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f776291b759
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 18 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:00007f77628d7168 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f77629a46c8 RCX: 00007f776291b759
RDX: 000000000000275a RSI: 0000000020000000 RDI: 00000000ffffff9c
RBP: 00007f77629a46c0 R08: 00007f77629a46c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f77629a46cc
R13: 0000000000000006 R14: 00007ffd59ba19f0 R15: 00007ffd59ba1ad8
 </TASK>
hfs: request for non-existent node 16777216 in B*Tree
hfs: request for non-existent node 16777216 in B*Tree
hfs: inconsistency in B*Tree (5,0,1,0,1)


---
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.

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