======================================================
WARNING: possible circular locking dependency detected
6.15.0-rc1-syzkaller-g0af2f6be1b42 #0 Not tainted
------------------------------------------------------
syz.3.709/10279 is trying to acquire lock:
ffff0000c6d70fd8 (sk_lock-AF_INET6){+.+.}-{0:0}, at: do_ipv6_setsockopt+0x9b4/0x30a0 net/ipv6/ipv6_sockglue.c:567

but task is already holding lock:
ffff8000930815a8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:80

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (rtnl_mutex){+.+.}-{4:4}:
       __mutex_lock_common+0x1f0/0x2604 kernel/locking/mutex.c:601
       __mutex_lock kernel/locking/mutex.c:746 [inline]
       mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:798
       rtnl_lock+0x20/0x2c net/core/rtnetlink.c:80
       start_sync_thread+0xe0/0x24bc net/netfilter/ipvs/ip_vs_sync.c:1761
       do_ip_vs_set_ctl+0x558/0xd84 net/netfilter/ipvs/ip_vs_ctl.c:2732
       nf_setsockopt+0x270/0x290 net/netfilter/nf_sockopt.c:101
       ip_setsockopt+0x118/0x128 net/ipv4/ip_sockglue.c:1424
       tcp_setsockopt+0xcc/0xe8 net/ipv4/tcp.c:4077
       sock_common_setsockopt+0xb0/0xcc net/core/sock.c:3889
       smc_setsockopt+0x1f8/0xd0c net/smc/af_smc.c:3081
       do_sock_setsockopt+0x2a0/0x4e0 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]
       __arm64_sys_setsockopt+0x170/0x1e0 net/socket.c:2324
       __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
       el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
       do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
       el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744
       el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
       el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600

-> #1 (&smc->clcsock_release_lock){+.+.}-{4:4}:
       __mutex_lock_common+0x1f0/0x2604 kernel/locking/mutex.c:601
       __mutex_lock kernel/locking/mutex.c:746 [inline]
       mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:798
       smc_switch_to_fallback+0x48/0xa7c net/smc/af_smc.c:903
       smc_sendmsg+0xfc/0x9f8 net/smc/af_smc.c:2781
       sock_sendmsg_nosec net/socket.c:712 [inline]
       __sock_sendmsg net/socket.c:727 [inline]
       ____sys_sendmsg+0x578/0x890 net/socket.c:2566
       ___sys_sendmsg net/socket.c:2620 [inline]
       __sys_sendmsg+0x238/0x304 net/socket.c:2652
       __do_sys_sendmsg net/socket.c:2657 [inline]
       __se_sys_sendmsg net/socket.c:2655 [inline]
       __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2655
       __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
       el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
       do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
       el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744
       el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
       el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600

-> #0 (sk_lock-AF_INET6){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3166 [inline]
       check_prevs_add kernel/locking/lockdep.c:3285 [inline]
       validate_chain kernel/locking/lockdep.c:3909 [inline]
       __lock_acquire+0x17b8/0x32c4 kernel/locking/lockdep.c:5235
       lock_acquire+0x150/0x2e8 kernel/locking/lockdep.c:5866
       lock_sock_nested net/core/sock.c:3697 [inline]
       lock_sock include/net/sock.h:1615 [inline]
       sockopt_lock_sock+0x88/0x148 net/core/sock.c:1148
       do_ipv6_setsockopt+0x9b4/0x30a0 net/ipv6/ipv6_sockglue.c:567
       ipv6_setsockopt+0x68/0x174 net/ipv6/ipv6_sockglue.c:993
       tcp_setsockopt+0xcc/0xe8 net/ipv4/tcp.c:4077
       sock_common_setsockopt+0xb0/0xcc net/core/sock.c:3889
       do_sock_setsockopt+0x2a0/0x4e0 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]
       __arm64_sys_setsockopt+0x170/0x1e0 net/socket.c:2324
       __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
       el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
       do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
       el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744
       el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
       el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600

other info that might help us debug this:

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

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

1 lock held by syz.3.709/10279:
 #0: ffff8000930815a8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:80

stack backtrace:
CPU: 1 UID: 0 PID: 10279 Comm: syz.3.709 Not tainted 6.15.0-rc1-syzkaller-g0af2f6be1b42 #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C)
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:120
 dump_stack+0x1c/0x28 lib/dump_stack.c:129
 print_circular_bug+0x32c/0x334 kernel/locking/lockdep.c:2079
 check_noncircular+0x15c/0x178 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 kernel/locking/lockdep.c:3909 [inline]
 __lock_acquire+0x17b8/0x32c4 kernel/locking/lockdep.c:5235
 lock_acquire+0x150/0x2e8 kernel/locking/lockdep.c:5866
 lock_sock_nested net/core/sock.c:3697 [inline]
 lock_sock include/net/sock.h:1615 [inline]
 sockopt_lock_sock+0x88/0x148 net/core/sock.c:1148
 do_ipv6_setsockopt+0x9b4/0x30a0 net/ipv6/ipv6_sockglue.c:567
 ipv6_setsockopt+0x68/0x174 net/ipv6/ipv6_sockglue.c:993
 tcp_setsockopt+0xcc/0xe8 net/ipv4/tcp.c:4077
 sock_common_setsockopt+0xb0/0xcc net/core/sock.c:3889
 do_sock_setsockopt+0x2a0/0x4e0 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]
 __arm64_sys_setsockopt+0x170/0x1e0 net/socket.c:2324
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
netlink: 'syz.3.709': attribute type 1 has an invalid length.
netlink: 244 bytes leftover after parsing attributes in process `syz.3.709'.
NCSI netlink: No device for ifindex 0