======================================================
WARNING: possible circular locking dependency detected
6.14.0-syzkaller-00685-g3ba7dfb8da62 #0 Not tainted
------------------------------------------------------
kworker/0:2/976 is trying to acquire lock:
ffffffff8fef8b68 (rtnl_mutex){+.+.}-{4:4}, at: smc_vlan_by_tcpsk+0x251/0x620 net/smc/smc_core.c:1908

but task is already holding lock:
ffff88805b97bbd8 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1624 [inline]
ffff88805b97bbd8 (sk_lock-AF_INET){+.+.}-{0:0}, at: smc_connect_work+0x53c/0xae0 net/smc/af_smc.c:1600

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (sk_lock-AF_INET){+.+.}-{0:0}:
       lock_sock_nested+0x3a/0xf0 net/core/sock.c:3662
       lock_sock include/net/sock.h:1624 [inline]
       sockopt_lock_sock net/core/sock.c:1133 [inline]
       sockopt_lock_sock+0x54/0x70 net/core/sock.c:1124
       do_ip_setsockopt+0xff/0x3280 net/ipv4/ip_sockglue.c:1078
       ip_setsockopt+0x59/0xf0 net/ipv4/ip_sockglue.c:1417
       raw_setsockopt+0xb8/0x2a0 net/ipv4/raw.c:845
       do_sock_setsockopt+0x222/0x480 net/socket.c:2303
       __sys_setsockopt+0x1a0/0x230 net/socket.c:2328
       __do_sys_setsockopt net/socket.c:2334 [inline]
       __se_sys_setsockopt net/socket.c:2331 [inline]
       __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2331
       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 (rtnl_mutex){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3163 [inline]
       check_prevs_add kernel/locking/lockdep.c:3282 [inline]
       validate_chain kernel/locking/lockdep.c:3906 [inline]
       __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5228
       lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5851
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730
       smc_vlan_by_tcpsk+0x251/0x620 net/smc/smc_core.c:1908
       __smc_connect+0x44d/0x4890 net/smc/af_smc.c:1520
       smc_connect_work+0x54f/0xae0 net/smc/af_smc.c:1613
       process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3238
       process_scheduled_works kernel/workqueue.c:3319 [inline]
       worker_thread+0x6c8/0xf00 kernel/workqueue.c:3400
       kthread+0x3af/0x750 kernel/kthread.c:464
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sk_lock-AF_INET);
                               lock(rtnl_mutex);
                               lock(sk_lock-AF_INET);
  lock(rtnl_mutex);

 *** DEADLOCK ***

3 locks held by kworker/0:2/976:
 #0: ffff88803203d148 ((wq_completion)smc_hs_wq){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3213
 #1: ffffc90003c17d18 ((work_completion)(&smc->connect_work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3214
 #2: ffff88805b97bbd8 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1624 [inline]
 #2: ffff88805b97bbd8 (sk_lock-AF_INET){+.+.}-{0:0}, at: smc_connect_work+0x53c/0xae0 net/smc/af_smc.c:1600

stack backtrace:
CPU: 0 UID: 0 PID: 976 Comm: kworker/0:2 Not tainted 6.14.0-syzkaller-00685-g3ba7dfb8da62 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: smc_hs_wq smc_connect_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x490/0x760 kernel/locking/lockdep.c:2076
 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2208
 check_prev_add kernel/locking/lockdep.c:3163 [inline]
 check_prevs_add kernel/locking/lockdep.c:3282 [inline]
 validate_chain kernel/locking/lockdep.c:3906 [inline]
 __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5228
 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5851
 __mutex_lock_common kernel/locking/mutex.c:585 [inline]
 __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730
 smc_vlan_by_tcpsk+0x251/0x620 net/smc/smc_core.c:1908
 __smc_connect+0x44d/0x4890 net/smc/af_smc.c:1520
 smc_connect_work+0x54f/0xae0 net/smc/af_smc.c:1613
 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3400
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>