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Subject[syzbot] [reiserfs?] possible deadlock in open_xa_dir
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Hello,

syzbot found the following issue on:

HEAD commit: 1b929c02afd3 Linux 6.2-rc1
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11da7f8c480000
kernel config: https://syzkaller.appspot.com/x/.config?x=2651619a26b4d687
dashboard link: https://syzkaller.appspot.com/bug?extid=8fb64a61fdd96b50f3b8
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d562ace1a56c/disk-1b929c02.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/39f000fe6b9e/vmlinux-1b929c02.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1c67e48de5a0/bzImage-1b929c02.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8fb64a61fdd96b50f3b8@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc1-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.1/19784 is trying to acquire lock:
ffff88807d682090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x79/0x100 fs/reiserfs/lock.c:27

but task is already holding lock:
ffff8880899d6ce0 (&type->i_mutex_dir_key#9/3){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:791 [inline]
ffff8880899d6ce0 (&type->i_mutex_dir_key#9/3){+.+.}-{3:3}, at: open_xa_root fs/reiserfs/xattr.c:127 [inline]
ffff8880899d6ce0 (&type->i_mutex_dir_key#9/3){+.+.}-{3:3}, at: open_xa_dir+0x127/0x830 fs/reiserfs/xattr.c:152

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&type->i_mutex_dir_key#9/3){+.+.}-{3:3}:
down_write_nested+0x98/0x220 kernel/locking/rwsem.c:1672
inode_lock_nested include/linux/fs.h:791 [inline]
open_xa_root fs/reiserfs/xattr.c:127 [inline]
open_xa_dir+0x127/0x830 fs/reiserfs/xattr.c:152
reiserfs_for_each_xattr+0x1ab/0x9a0 fs/reiserfs/xattr.c:252
reiserfs_delete_xattrs+0x20/0xa0 fs/reiserfs/xattr.c:364
reiserfs_evict_inode+0x2e7/0x540 fs/reiserfs/inode.c:53
evict+0x2ed/0x6b0 fs/inode.c:664
iput_final fs/inode.c:1747 [inline]
iput.part.0+0x59b/0x880 fs/inode.c:1773
iput+0x5c/0x80 fs/inode.c:1763
reiserfs_create+0x65a/0x730 fs/reiserfs/namei.c:688
vfs_create fs/namei.c:3115 [inline]
vfs_create+0x3ed/0x670 fs/namei.c:3101
do_mknodat+0x3c4/0x510 fs/namei.c:3965
__do_sys_mknod fs/namei.c:3998 [inline]
__se_sys_mknod fs/namei.c:3996 [inline]
__x64_sys_mknod+0x11e/0x180 fs/namei.c:3996
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&sbi->lock){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3097 [inline]
check_prevs_add kernel/locking/lockdep.c:3216 [inline]
validate_chain kernel/locking/lockdep.c:3831 [inline]
__lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055
lock_acquire kernel/locking/lockdep.c:5668 [inline]
lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x12f/0x1360 kernel/locking/mutex.c:747
reiserfs_write_lock+0x79/0x100 fs/reiserfs/lock.c:27
reiserfs_mkdir+0x31c/0x990 fs/reiserfs/namei.c:831
xattr_mkdir fs/reiserfs/xattr.c:76 [inline]
open_xa_root fs/reiserfs/xattr.c:136 [inline]
open_xa_dir+0x6a3/0x830 fs/reiserfs/xattr.c:152
xattr_lookup+0x21/0x3d0 fs/reiserfs/xattr.c:395
reiserfs_xattr_set_handle+0xfb/0xb00 fs/reiserfs/xattr.c:533
reiserfs_xattr_set+0x454/0x5b0 fs/reiserfs/xattr.c:633
trusted_set+0xa7/0xd0 fs/reiserfs/xattr_trusted.c:31
__vfs_setxattr+0x173/0x1e0 fs/xattr.c:202
__vfs_setxattr_noperm+0x129/0x5f0 fs/xattr.c:236
__vfs_setxattr_locked+0x1d3/0x260 fs/xattr.c:297
vfs_setxattr+0x143/0x340 fs/xattr.c:323
do_setxattr+0x151/0x190 fs/xattr.c:608
setxattr+0x146/0x160 fs/xattr.c:631
path_setxattr+0x197/0x1c0 fs/xattr.c:650
__do_sys_setxattr fs/xattr.c:666 [inline]
__se_sys_setxattr fs/xattr.c:662 [inline]
__x64_sys_setxattr+0xc4/0x160 fs/xattr.c:662
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 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(&type->i_mutex_dir_key#9/3);
lock(&sbi->lock);
lock(&type->i_mutex_dir_key#9/3);
lock(&sbi->lock);

*** DEADLOCK ***

3 locks held by syz-executor.1/19784:
#0: ffff88801c7fe460 (sb_writers#17){.+.+}-{0:0}, at: path_setxattr+0xb2/0x1c0 fs/xattr.c:648
#1: ffff8880899d7a20 (&type->i_mutex_dir_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
#1: ffff8880899d7a20 (&type->i_mutex_dir_key#9){++++}-{3:3}, at: vfs_setxattr+0x120/0x340 fs/xattr.c:322
#2: ffff8880899d6ce0 (&type->i_mutex_dir_key#9/3){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:791 [inline]
#2: ffff8880899d6ce0 (&type->i_mutex_dir_key#9/3){+.+.}-{3:3}, at: open_xa_root fs/reiserfs/xattr.c:127 [inline]
#2: ffff8880899d6ce0 (&type->i_mutex_dir_key#9/3){+.+.}-{3:3}, at: open_xa_dir+0x127/0x830 fs/reiserfs/xattr.c:152

stack backtrace:
CPU: 1 PID: 19784 Comm: syz-executor.1 Not tainted 6.2.0-rc1-syzkaller #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+0xd1/0x138 lib/dump_stack.c:106
check_noncircular+0x25f/0x2e0 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 kernel/locking/lockdep.c:3831 [inline]
__lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055
lock_acquire kernel/locking/lockdep.c:5668 [inline]
lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x12f/0x1360 kernel/locking/mutex.c:747
reiserfs_write_lock+0x79/0x100 fs/reiserfs/lock.c:27
reiserfs_mkdir+0x31c/0x990 fs/reiserfs/namei.c:831
xattr_mkdir fs/reiserfs/xattr.c:76 [inline]
open_xa_root fs/reiserfs/xattr.c:136 [inline]
open_xa_dir+0x6a3/0x830 fs/reiserfs/xattr.c:152
xattr_lookup+0x21/0x3d0 fs/reiserfs/xattr.c:395
reiserfs_xattr_set_handle+0xfb/0xb00 fs/reiserfs/xattr.c:533
reiserfs_xattr_set+0x454/0x5b0 fs/reiserfs/xattr.c:633
trusted_set+0xa7/0xd0 fs/reiserfs/xattr_trusted.c:31
__vfs_setxattr+0x173/0x1e0 fs/xattr.c:202
__vfs_setxattr_noperm+0x129/0x5f0 fs/xattr.c:236
__vfs_setxattr_locked+0x1d3/0x260 fs/xattr.c:297
vfs_setxattr+0x143/0x340 fs/xattr.c:323
do_setxattr+0x151/0x190 fs/xattr.c:608
setxattr+0x146/0x160 fs/xattr.c:631
path_setxattr+0x197/0x1c0 fs/xattr.c:650
__do_sys_setxattr fs/xattr.c:666 [inline]
__se_sys_setxattr fs/xattr.c:662 [inline]
__x64_sys_setxattr+0xc4/0x160 fs/xattr.c:662
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fd78168c0a9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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:00007fd78242a168 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007fd7817abf80 RCX: 00007fd78168c0a9
RDX: 0000000020000440 RSI: 00000000200002c0 RDI: 0000000020000280
RBP: 00007fd7816e7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000010c R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff9b71513f R14: 00007fd78242a300 R15: 0000000000022000
</TASK>
REISERFS warning (device loop1): vs-13060 reiserfs_update_sd_size: stat data of object [3 6 0x0 SD] (nlink == 2) not found (pos 5)
REISERFS warning (device loop1): vs-13060 reiserfs_update_sd_size: stat data of object [3 6 0x0 SD] (nlink == 3) not found (pos 3)


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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