[syzbot] [smc?] possible deadlock in __smc_lgr_terminate

[syzbot <syzbot+7ea1f5efd5de7e24f1de@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    f47d223627f8 Merge tag 'vfs-7.4-rc1.sync_close' of git://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1413290d580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b8fd4ba7675545d0
dashboard link: https://syzkaller.appspot.com/bug?extid=7ea1f5efd5de7e24f1de
compiler:       Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/54bd1c4ffe03/disk-f47d2236.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7c7d29f96e65/vmlinux-f47d2236.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6342fb551ce8/bzImage-f47d2236.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7ea1f5efd5de7e24f1de@syzkaller.appspotmail.com

============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
kworker/0:2/7972 is trying to acquire lock:
ffff8880419c3118 (sk_lock-AF_SMC){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1715 [inline]
ffff8880419c3118 (sk_lock-AF_SMC){+.+.}-{0:0}, at: __smc_lgr_terminate+0x19e/0x6a0 net/smc/smc_core.c:1580

but task is already holding lock:
ffff8880326f9298 (sk_lock-AF_SMC){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1715 [inline]
ffff8880326f9298 (sk_lock-AF_SMC){+.+.}-{0:0}, at: smc_listen_work+0x5e/0x1410 net/smc/af_smc.c:2463

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

       CPU0
       ----
  lock(sk_lock-AF_SMC);
  lock(sk_lock-AF_SMC);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

locks held by kworker/0:2/7972: 3, last CPU#0:
 #0: ffff8880344a4938 ((wq_completion)smc_hs_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff8880344a4938 ((wq_completion)smc_hs_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff8880344a4938 ((wq_completion)smc_hs_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff8880344a4938 ((wq_completion)smc_hs_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc900045ffc40 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc900045ffc40 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc900045ffc40 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc900045ffc40 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #2: ffff8880326f9298 (sk_lock-AF_SMC){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1715 [inline]
 #2: ffff8880326f9298 (sk_lock-AF_SMC){+.+.}-{0:0}, at: smc_listen_work+0x5e/0x1410 net/smc/af_smc.c:2463

stack backtrace:
CPU: 0 UID: 0 PID: 7972 Comm: kworker/0:2 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Workqueue: smc_hs_wq smc_listen_work
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_deadlock_bug+0x27a/0x290 kernel/locking/lockdep.c:3085
 check_deadlock kernel/locking/lockdep.c:3137 [inline]
 validate_chain kernel/locking/lockdep.c:3939 [inline]
 __lock_acquire+0x25db/0x2de0 kernel/locking/lockdep.c:5288
 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
 lock_sock_nested+0x41/0x130 net/core/sock.c:3865
 lock_sock include/net/sock.h:1715 [inline]
 __smc_lgr_terminate+0x19e/0x6a0 net/smc/smc_core.c:1580
 smc_conn_abort net/smc/af_smc.c:1019 [inline]
 smc_listen_decline net/smc/af_smc.c:1978 [inline]
 smc_listen_work+0x69e/0x1410 net/smc/af_smc.c:2588
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>


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