| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <6835a50b.a70a0220.253bc2.00af.GAE@google.com>
Date: Tue, 27 May 2025 04:42:03 -0700
From: syzbot <syzbot+2e9e529ac0b319316453@...kaller.appspotmail.com>
To: hdanton@...a.com, linux-kernel@...r.kernel.org,
syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [block?] possible deadlock in __del_gendisk
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
possible deadlock in __del_gendisk
======================================================
WARNING: possible circular locking dependency detected
6.15.0-syzkaller-g914873bc7df9-dirty #0 Not tainted
------------------------------------------------------
kworker/u4:1/13 is trying to acquire lock:
ffff888059e20358 (&disk->open_mutex){+.+.}-{4:4}, at: __del_gendisk+0x129/0x9e0 block/genhd.c:706
but task is already holding lock:
ffff888053877188 (&set->update_nr_hwq_lock){++++}-{4:4}, at: del_gendisk+0xe0/0x160 block/genhd.c:818
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&set->update_nr_hwq_lock){++++}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
down_write+0x96/0x1f0 kernel/locking/rwsem.c:1577
blk_mq_update_nr_hw_queues+0x3b/0x14c0 block/blk-mq.c:5041
nbd_start_device+0x16c/0xac0 drivers/block/nbd.c:1476
nbd_genl_connect+0x1250/0x1930 drivers/block/nbd.c:2201
genl_family_rcv_msg_doit+0x212/0x300 net/netlink/genetlink.c:1115
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x21c/0x490 net/netlink/af_netlink.c:2534
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
netlink_unicast+0x758/0x8d0 net/netlink/af_netlink.c:1339
netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1883
sock_sendmsg_nosec net/socket.c:712 [inline]
__sock_sendmsg+0x21c/0x270 net/socket.c:727
____sys_sendmsg+0x505/0x830 net/socket.c:2566
___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620
__sys_sendmsg net/socket.c:2652 [inline]
__do_sys_sendmsg net/socket.c:2657 [inline]
__se_sys_sendmsg net/socket.c:2655 [inline]
__x64_sys_sendmsg+0x19b/0x260 net/socket.c:2655
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf6/0x220 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #2 (&nbd->config_lock){+.+.}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
__mutex_lock_common kernel/locking/mutex.c:601 [inline]
__mutex_lock+0x182/0xe80 kernel/locking/mutex.c:746
nbd_open+0x2b7/0x5d0 drivers/block/nbd.c:1703
blkdev_get_whole+0x98/0x510 block/bdev.c:730
bdev_open+0x31e/0xd30 block/bdev.c:957
blkdev_open+0x3a8/0x510 block/fops.c:676
do_dentry_open+0xdf3/0x1970 fs/open.c:964
vfs_open+0x3b/0x340 fs/open.c:1094
do_open fs/namei.c:3887 [inline]
path_openat+0x2ee5/0x3830 fs/namei.c:4046
do_filp_open+0x1fa/0x410 fs/namei.c:4073
do_sys_openat2+0x121/0x1c0 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+0x138/0x170 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf6/0x220 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (nbd_index_mutex){+.+.}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
__mutex_lock_common kernel/locking/mutex.c:601 [inline]
__mutex_lock+0x182/0xe80 kernel/locking/mutex.c:746
nbd_open+0x7b/0x5d0 drivers/block/nbd.c:1690
blkdev_get_whole+0x98/0x510 block/bdev.c:730
bdev_open+0x31e/0xd30 block/bdev.c:957
blkdev_open+0x3a8/0x510 block/fops.c:676
do_dentry_open+0xdf3/0x1970 fs/open.c:964
vfs_open+0x3b/0x340 fs/open.c:1094
do_open fs/namei.c:3887 [inline]
path_openat+0x2ee5/0x3830 fs/namei.c:4046
do_filp_open+0x1fa/0x410 fs/namei.c:4073
do_sys_openat2+0x121/0x1c0 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+0x138/0x170 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf6/0x220 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&disk->open_mutex){+.+.}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3168 [inline]
check_prevs_add kernel/locking/lockdep.c:3287 [inline]
validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
__mutex_lock_common kernel/locking/mutex.c:601 [inline]
__mutex_lock+0x182/0xe80 kernel/locking/mutex.c:746
__del_gendisk+0x129/0x9e0 block/genhd.c:706
del_gendisk+0xe8/0x160 block/genhd.c:819
nbd_dev_remove drivers/block/nbd.c:268 [inline]
nbd_dev_remove_work+0x47/0xe0 drivers/block/nbd.c:284
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xade/0x17a0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x70e/0x8a0 kernel/kthread.c:464
ret_from_fork+0x4e/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
other info that might help us debug this:
Chain exists of:
&disk->open_mutex --> &nbd->config_lock --> &set->update_nr_hwq_lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
rlock(&set->update_nr_hwq_lock);
lock(&nbd->config_lock);
lock(&set->update_nr_hwq_lock);
lock(&disk->open_mutex);
*** DEADLOCK ***
3 locks held by kworker/u4:1/13:
#0: ffff888000b13148 ((wq_completion)nbd-del){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
#0: ffff888000b13148 ((wq_completion)nbd-del){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319
#1: ffffc900001f7c60 ((work_completion)(&nbd->remove_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
#1: ffffc900001f7c60 ((work_completion)(&nbd->remove_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319
#2: ffff888053877188 (&set->update_nr_hwq_lock){++++}-{4:4}, at: del_gendisk+0xe0/0x160 block/genhd.c:818
stack backtrace:
CPU: 0 UID: 0 PID: 13 Comm: kworker/u4:1 Not tainted 6.15.0-syzkaller-g914873bc7df9-dirty #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: nbd-del nbd_dev_remove_work
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2046
check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2178
check_prev_add kernel/locking/lockdep.c:3168 [inline]
check_prevs_add kernel/locking/lockdep.c:3287 [inline]
validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
__mutex_lock_common kernel/locking/mutex.c:601 [inline]
__mutex_lock+0x182/0xe80 kernel/locking/mutex.c:746
__del_gendisk+0x129/0x9e0 block/genhd.c:706
del_gendisk+0xe8/0x160 block/genhd.c:819
nbd_dev_remove drivers/block/nbd.c:268 [inline]
nbd_dev_remove_work+0x47/0xe0 drivers/block/nbd.c:284
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xade/0x17a0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x70e/0x8a0 kernel/kthread.c:464
ret_from_fork+0x4e/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
Tested on:
commit: 914873bc Merge tag 'x86-build-2025-05-25' of git://git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=141fbdf4580000
kernel config: https://syzkaller.appspot.com/x/.config?x=eeb82b5d1d67d535
dashboard link: https://syzkaller.appspot.com/bug?extid=2e9e529ac0b319316453
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
patch: https://syzkaller.appspot.com/x/patch.diff?x=13f7bdf4580000
Powered by blists - more mailing lists