[syzbot] [net?] [s390?] possible deadlock in smc_shutdown

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1dfe225e9af5 Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14202469980000
kernel config: https://syzkaller.appspot.com/x/.config?x=de2d4dc103148cd6
dashboard link: https://syzkaller.appspot.com/bug?extid=60e37f9e2f4575eab889
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-1dfe225e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1a8b8f1ba6ff/vmlinux-1dfe225e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/615b64310209/bzImage-1dfe225e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+60e37f...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.10.0-rc6-syzkaller-00051-g1dfe225e9af5 #0 Not tainted
------------------------------------------------------
syz.1.5756/20250 is trying to acquire lock:
ffff888043bbf058 (sk_lock-AF_SMC){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1602 [inline]
ffff888043bbf058 (sk_lock-AF_SMC){+.+.}-{0:0}, at: smc_shutdown+0x65/0x800 net/smc/af_smc.c:2912

but task is already holding lock:
ffff8880210a2970 (&nsock->tx_lock){+.+.}-{3:3}, at: sock_shutdown+0x16f/0x280 drivers/block/nbd.c:395

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #7 (&nsock->tx_lock){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
send_disconnects drivers/block/nbd.c:1312 [inline]
nbd_disconnect+0x321/0x540 drivers/block/nbd.c:1328
nbd_disconnect_and_put+0x2c/0x170 drivers/block/nbd.c:2155
nbd_genl_disconnect+0x398/0x570 drivers/block/nbd.c:2200
genl_family_rcv_msg_doit+0x202/0x2f0 net/netlink/genetlink.c:1115
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x565/0x800 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2564
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
netlink_unicast+0x542/0x820 net/netlink/af_netlink.c:1361
netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1905
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0xab5/0xc90 net/socket.c:2585
___sys_sendmsg+0x135/0x1e0 net/socket.c:2639
__sys_sendmsg+0x117/0x1f0 net/socket.c:2668
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #6 (&nbd->config_lock){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
refcount_dec_and_mutex_lock+0x51/0xe0 lib/refcount.c:118
nbd_config_put+0x31/0x750 drivers/block/nbd.c:1341
nbd_release+0xb7/0x190 drivers/block/nbd.c:1653
blkdev_put_whole+0xad/0xf0 block/bdev.c:673
bdev_release+0x496/0x6f0 block/bdev.c:1096
blkdev_release+0x15/0x20 block/fops.c:623
__fput+0x408/0xbb0 fs/file_table.c:422
__fput_sync+0x47/0x50 fs/file_table.c:507
__do_sys_close fs/open.c:1563 [inline]
__se_sys_close fs/open.c:1548 [inline]
__x64_sys_close+0x86/0x100 fs/open.c:1548
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #5 (&disk->open_mutex){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
bdev_open+0x41a/0xe50 block/bdev.c:897
bdev_file_open_by_dev block/bdev.c:1011 [inline]
bdev_file_open_by_dev+0x17d/0x210 block/bdev.c:986
disk_scan_partitions+0x1ed/0x320 block/genhd.c:367
device_add_disk+0xe97/0x1250 block/genhd.c:510
pmem_attach_disk+0x9fe/0x1400 drivers/nvdimm/pmem.c:578
nd_pmem_probe+0x1a9/0x1f0 drivers/nvdimm/pmem.c:651
nvdimm_bus_probe+0x169/0x5d0 drivers/nvdimm/bus.c:91
call_driver_probe drivers/base/dd.c:578 [inline]
really_probe+0x23e/0xa90 drivers/base/dd.c:656
__driver_probe_device+0x1de/0x440 drivers/base/dd.c:798
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:828
__driver_attach+0x283/0x580 drivers/base/dd.c:1214
bus_for_each_dev+0x13c/0x1d0 drivers/base/bus.c:368
bus_add_driver+0x2e9/0x690 drivers/base/bus.c:673
driver_register+0x15c/0x4b0 drivers/base/driver.c:246
__nd_driver_register+0x103/0x1a0 drivers/nvdimm/bus.c:619
do_one_initcall+0x128/0x700 init/main.c:1267
do_initcall_level init/main.c:1329 [inline]
do_initcalls init/main.c:1345 [inline]
do_basic_setup init/main.c:1364 [inline]
kernel_init_freeable+0x69d/0xca0 init/main.c:1578
kernel_init+0x1c/0x2b0 init/main.c:1467
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #4 (&nvdimm_namespace_key){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
device_lock include/linux/device.h:1009 [inline]
uevent_show+0x188/0x3b0 drivers/base/core.c:2743
dev_attr_show+0x53/0xe0 drivers/base/core.c:2437
sysfs_kf_seq_show+0x23e/0x410 fs/sysfs/file.c:59
seq_read_iter+0x4fa/0x12c0 fs/seq_file.c:230
kernfs_fop_read_iter+0x41a/0x590 fs/kernfs/file.c:279
new_sync_read fs/read_write.c:395 [inline]
vfs_read+0x869/0xbd0 fs/read_write.c:476
ksys_read+0x12f/0x260 fs/read_write.c:619
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3 (kn->active#5){++++}-{0:0}:
kernfs_drain+0x48f/0x590 fs/kernfs/dir.c:500
__kernfs_remove+0x281/0x670 fs/kernfs/dir.c:1486
kernfs_remove_by_name_ns+0xb2/0x130 fs/kernfs/dir.c:1694
sysfs_remove_file include/linux/sysfs.h:773 [inline]
device_remove_file drivers/base/core.c:3061 [inline]
device_remove_file drivers/base/core.c:3057 [inline]
device_del+0x381/0x9f0 drivers/base/core.c:3866
unregister_netdevice_many_notify+0xc8a/0x19f0 net/core/dev.c:11249
unregister_netdevice_many net/core/dev.c:11277 [inline]
unregister_netdevice_queue+0x307/0x3f0 net/core/dev.c:11156
unregister_netdevice include/linux/netdevice.h:3119 [inline]
unregister_netdev+0x1c/0x30 net/core/dev.c:11295
gprs_attach+0x4ce/0x5e0 net/phonet/pep-gprs.c:291
pep_setsockopt+0x419/0x510 net/phonet/pep.c:1031
do_sock_setsockopt+0x222/0x480 net/socket.c:2312
__sys_setsockopt+0x1a4/0x270 net/socket.c:2335
__do_sys_setsockopt net/socket.c:2344 [inline]
__se_sys_setsockopt net/socket.c:2341 [inline]
__x64_sys_setsockopt+0xbd/0x160 net/socket.c:2341
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (rtnl_mutex){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
do_ipv6_setsockopt+0x2162/0x47b0 net/ipv6/ipv6_sockglue.c:567
ipv6_setsockopt+0xe3/0x1a0 net/ipv6/ipv6_sockglue.c:994
tcp_setsockopt+0xa4/0x100 net/ipv4/tcp.c:3765
smc_setsockopt+0x1b4/0xa00 net/smc/af_smc.c:3063
do_sock_setsockopt+0x222/0x480 net/socket.c:2312
__sys_setsockopt+0x1a4/0x270 net/socket.c:2335
__do_sys_setsockopt net/socket.c:2344 [inline]
__se_sys_setsockopt net/socket.c:2341 [inline]
__x64_sys_setsockopt+0xbd/0x160 net/socket.c:2341
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&smc->clcsock_release_lock){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
smc_switch_to_fallback+0x2d/0xa00 net/smc/af_smc.c:893
smc_sendmsg+0x13d/0x520 net/smc/af_smc.c:2770
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0xab5/0xc90 net/socket.c:2585
___sys_sendmsg+0x135/0x1e0 net/socket.c:2639
__sys_sendmmsg+0x1a1/0x450 net/socket.c:2725
__do_sys_sendmmsg net/socket.c:2754 [inline]
__se_sys_sendmmsg net/socket.c:2751 [inline]
__x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2751
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (sk_lock-AF_SMC){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
lock_sock_nested+0x3a/0xf0 net/core/sock.c:3534
lock_sock include/net/sock.h:1602 [inline]
smc_shutdown+0x65/0x800 net/smc/af_smc.c:2912
nbd_mark_nsock_dead+0xae/0x5d0 drivers/block/nbd.c:303
sock_shutdown+0x17c/0x280 drivers/block/nbd.c:396
nbd_clear_sock drivers/block/nbd.c:1334 [inline]
nbd_clear_sock_ioctl drivers/block/nbd.c:1472 [inline]
__nbd_ioctl drivers/block/nbd.c:1500 [inline]
nbd_ioctl+0x49b/0xfd0 drivers/block/nbd.c:1560
blkdev_ioctl+0x27c/0x6e0 block/ioctl.c:676
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl fs/ioctl.c:893 [inline]
__x64_sys_ioctl+0x193/0x220 fs/ioctl.c:893
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
sk_lock-AF_SMC --> &nbd->config_lock --> &nsock->tx_lock

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&nsock->tx_lock);
lock(&nbd->config_lock);
lock(&nsock->tx_lock);
lock(sk_lock-AF_SMC);

*** DEADLOCK ***

2 locks held by syz.1.5756/20250:
#0: ffff888021dd2198 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x151/0xfd0 drivers/block/nbd.c:1553
#1: ffff8880210a2970 (&nsock->tx_lock){+.+.}-{3:3}, at: sock_shutdown+0x16f/0x280 drivers/block/nbd.c:395

stack backtrace:
CPU: 0 PID: 20250 Comm: syz.1.5756 Not tainted 6.10.0-rc6-syzkaller-00051-g1dfe225e9af5 #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:88 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
lock_sock_nested+0x3a/0xf0 net/core/sock.c:3534
lock_sock include/net/sock.h:1602 [inline]
smc_shutdown+0x65/0x800 net/smc/af_smc.c:2912
nbd_mark_nsock_dead+0xae/0x5d0 drivers/block/nbd.c:303
sock_shutdown+0x17c/0x280 drivers/block/nbd.c:396
nbd_clear_sock drivers/block/nbd.c:1334 [inline]
nbd_clear_sock_ioctl drivers/block/nbd.c:1472 [inline]
__nbd_ioctl drivers/block/nbd.c:1500 [inline]
nbd_ioctl+0x49b/0xfd0 drivers/block/nbd.c:1560
blkdev_ioctl+0x27c/0x6e0 block/ioctl.c:676
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl fs/ioctl.c:893 [inline]
__x64_sys_ioctl+0x193/0x220 fs/ioctl.c:893
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc301975ed9
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:00007fc302792048 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc301b04038 RCX: 00007fc301975ed9
RDX: 0000000000000000 RSI: 000000000000ab04 RDI: 0000000000000003
RBP: 00007fc3019e49e5 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007fc301b04038 R15: 00007ffc819d5788
</TASK>
block nbd1: shutting down sockets


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup