Re: [syzbot] [hfs?] possible deadlock in hfsplus_file_extend (2)

[syzbot <syzbot+4cba2fd444e9a16ae758@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
possible deadlock in hfsplus_bmap_reserve

loop0: detected capacity change from 0 to 1024
hfsplus: inconsistency in B*Tree (128,1,255,1,0)
============================================
WARNING: possible recursive locking detected
6.12.0-rc7-syzkaller-g2d5404caa8c7-dirty #0 Not tainted
--------------------------------------------
syz.0.15/5813 is trying to acquire lock:
ffff888036820108 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_bmap_reserve+0x119/0x500 fs/hfsplus/btree.c:358

but task is already holding lock:
ffff888036820e88 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_bmap_reserve+0x119/0x500 fs/hfsplus/btree.c:358

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

       CPU0
       ----
  lock(&HFSPLUS_I(inode)->extents_lock);
  lock(&HFSPLUS_I(inode)->extents_lock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

6 locks held by syz.0.15/5813:
 #0: ffff888056c0c420 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
 #1: ffff8880368224b8 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline]
 #1: ffff8880368224b8 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: vfs_setxattr+0x1e1/0x430 fs/xattr.c:320
 #2: ffff888034b200b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_find_init+0x14a/0x1c0 fs/hfsplus/bfind.c:28
 #3: ffff8880574a20b0 (&tree->tree_lock/2){+.+.}-{3:3}, at: hfsplus_find_init+0x14a/0x1c0 fs/hfsplus/bfind.c:28
 #4: ffff888036820e88 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_bmap_reserve+0x119/0x500 fs/hfsplus/btree.c:358
 #5: ffff888038c7e0b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfsplus_find_init+0x14a/0x1c0 fs/hfsplus/bfind.c:28

stack backtrace:
CPU: 0 UID: 0 PID: 5813 Comm: syz.0.15 Not tainted 6.12.0-rc7-syzkaller-g2d5404caa8c7-dirty #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3037
 check_deadlock kernel/locking/lockdep.c:3089 [inline]
 validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3891
 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
 hfsplus_bmap_reserve+0x119/0x500 fs/hfsplus/btree.c:358
 __hfsplus_ext_write_extent+0x2a4/0x5c0 fs/hfsplus/extents.c:104
 __hfsplus_ext_cache_extent+0x84/0xe10 fs/hfsplus/extents.c:186
 hfsplus_ext_read_extent fs/hfsplus/extents.c:218 [inline]
 hfsplus_file_extend+0x43f/0x1ac0 fs/hfsplus/extents.c:463
 hfsplus_bmap_reserve+0x12c/0x500 fs/hfsplus/btree.c:359
 hfsplus_create_attr+0x1c8/0x640 fs/hfsplus/attributes.c:221
 __hfsplus_setxattr+0x702/0x22d0 fs/hfsplus/xattr.c:356
 hfsplus_setxattr+0xb0/0xe0 fs/hfsplus/xattr.c:434
 hfsplus_trusted_setxattr+0x40/0x60 fs/hfsplus/xattr_trusted.c:30
 __vfs_setxattr+0x468/0x4a0 fs/xattr.c:200
 __vfs_setxattr_noperm+0x12e/0x660 fs/xattr.c:234
 vfs_setxattr+0x221/0x430 fs/xattr.c:321
 do_setxattr fs/xattr.c:629 [inline]
 path_setxattr+0x37e/0x4d0 fs/xattr.c:658
 __do_sys_lsetxattr fs/xattr.c:683 [inline]
 __se_sys_lsetxattr fs/xattr.c:679 [inline]
 __x64_sys_lsetxattr+0xb8/0xd0 fs/xattr.c:679
 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: 0033:0x7f2ade37e719
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:00007f2adf11d038 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd
RAX: ffffffffffffffda RBX: 00007f2ade535f80 RCX: 00007f2ade37e719
RDX: 0000000000000000 RSI: 0000000020000200 RDI: 0000000020000040
RBP: 00007f2ade3f139e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f2ade535f80 R15: 00007ffd3661a948
 </TASK>


Tested on:

commit:         2d5404ca Linux 6.12-rc7
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=127734e8580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d2aeec8c0b2e420c
dashboard link: https://syzkaller.appspot.com/bug?extid=4cba2fd444e9a16ae758
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=10d9d8c0580000