======================================================
WARNING: possible circular locking dependency detected
6.14.0-syzkaller-13189-ge48e99b6edf4 #0 Not tainted
------------------------------------------------------
syz.1.2241/14056 is trying to acquire lock:
ffffffff900fc808 (rtnl_mutex){+.+.}-{4:4}, at: ipv6_sock_ac_close+0xc9/0x130 net/ipv6/anycast.c:220

but task is already holding lock:
ffff88802a0122a0 (&smc->clcsock_release_lock){+.+.}-{4:4}, at: smc_clcsock_release+0x82/0xf0 net/smc/smc_close.c:30

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&smc->clcsock_release_lock){+.+.}-{4:4}:
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746
       smc_switch_to_fallback+0x35/0xda0 net/smc/af_smc.c:903
       smc_setsockopt+0x765/0xd50 net/smc/af_smc.c:3104
       do_sock_setsockopt+0x3b1/0x710 net/socket.c:2296
       __sys_setsockopt net/socket.c:2321 [inline]
       __do_sys_setsockopt net/socket.c:2327 [inline]
       __se_sys_setsockopt net/socket.c:2324 [inline]
       __x64_sys_setsockopt+0x1ee/0x280 net/socket.c:2324
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (sk_lock-AF_INET6){+.+.}-{0:0}:
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       lock_sock_nested+0x48/0x100 net/core/sock.c:3697
       do_ipv6_setsockopt+0xccd/0x3680 net/ipv6/ipv6_sockglue.c:567
       ipv6_setsockopt+0x5d/0x170 net/ipv6/ipv6_sockglue.c:993
       do_sock_setsockopt+0x3b1/0x710 net/socket.c:2296
       __sys_setsockopt net/socket.c:2321 [inline]
       __do_sys_setsockopt net/socket.c:2327 [inline]
       __se_sys_setsockopt net/socket.c:2324 [inline]
       __x64_sys_setsockopt+0x1ee/0x280 net/socket.c:2324
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (rtnl_mutex){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3166 [inline]
       check_prevs_add kernel/locking/lockdep.c:3285 [inline]
       validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909
       __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746
       ipv6_sock_ac_close+0xc9/0x130 net/ipv6/anycast.c:220
       inet6_release+0x4f/0x70 net/ipv6/af_inet6.c:485
       __sock_release net/socket.c:647 [inline]
       sock_release+0x82/0x150 net/socket.c:675
       smc_clcsock_release+0xcc/0xf0 net/smc/smc_close.c:34
       __smc_release+0x683/0x800 net/smc/af_smc.c:301
       smc_release+0x2dc/0x540 net/smc/af_smc.c:344
       __sock_release net/socket.c:647 [inline]
       sock_close+0xbc/0x240 net/socket.c:1391
       __fput+0x3e9/0x9f0 fs/file_table.c:465
       task_work_run+0x251/0x310 kernel/task_work.c:227
       resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
       exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
       __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
       syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
       do_syscall_64+0x100/0x230 arch/x86/entry/syscall_64.c:100
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  rtnl_mutex --> sk_lock-AF_INET6 --> &smc->clcsock_release_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&smc->clcsock_release_lock);
                               lock(sk_lock-AF_INET6);
                               lock(&smc->clcsock_release_lock);
  lock(rtnl_mutex);

 *** DEADLOCK ***

2 locks held by syz.1.2241/14056:
 #0: ffff88804d82d608 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #0: ffff88804d82d608 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: __sock_release net/socket.c:646 [inline]
 #0: ffff88804d82d608 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: sock_close+0x90/0x240 net/socket.c:1391
 #1: ffff88802a0122a0 (&smc->clcsock_release_lock){+.+.}-{4:4}, at: smc_clcsock_release+0x82/0xf0 net/smc/smc_close.c:30

stack backtrace:
CPU: 0 UID: 0 PID: 14056 Comm: syz.1.2241 Not tainted 6.14.0-syzkaller-13189-ge48e99b6edf4 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2079
 check_noncircular+0x142/0x160 kernel/locking/lockdep.c:2211
 check_prev_add kernel/locking/lockdep.c:3166 [inline]
 check_prevs_add kernel/locking/lockdep.c:3285 [inline]
 validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909
 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235
 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
 __mutex_lock_common kernel/locking/mutex.c:601 [inline]
 __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:746
 ipv6_sock_ac_close+0xc9/0x130 net/ipv6/anycast.c:220
 inet6_release+0x4f/0x70 net/ipv6/af_inet6.c:485
 __sock_release net/socket.c:647 [inline]
 sock_release+0x82/0x150 net/socket.c:675
 smc_clcsock_release+0xcc/0xf0 net/smc/smc_close.c:34
 __smc_release+0x683/0x800 net/smc/af_smc.c:301
 smc_release+0x2dc/0x540 net/smc/af_smc.c:344
 __sock_release net/socket.c:647 [inline]
 sock_close+0xbc/0x240 net/socket.c:1391
 __fput+0x3e9/0x9f0 fs/file_table.c:465
 task_work_run+0x251/0x310 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0630d8d169
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:00007f06310cfb88 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00000000000ac6c8 RCX: 00007f0630d8d169
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f0630fa7ba0 R08: 0000000000000001 R09: 00000005310cfe7f
R10: 00007f0630c00000 R11: 0000000000000246 R12: 00007f0630fa5fac
R13: 00007f0630fa5fa0 R14: ffffffffffffffff R15: 00007f06310cfca0
 </TASK>