======================================================
WARNING: possible circular locking dependency detected
6.15.0-rc2-syzkaller-gc72692105976 #0 Not tainted
------------------------------------------------------
syz.3.77/7001 is trying to acquire lock:
ffff800093071868 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:80

but task is already holding lock:
ffff0000f6370aa8 (&smc->clcsock_release_lock){+.+.}-{4:4}, at: smc_setsockopt+0x170/0xd0c net/smc/af_smc.c:3073

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&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_sendto+0x360/0x4d8 net/socket.c:2180
       __do_sys_sendto net/socket.c:2187 [inline]
       __se_sys_sendto net/socket.c:2183 [inline]
       __arm64_sys_sendto+0xd8/0xf8 net/socket.c:2183
       __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 (sk_lock-AF_INET){+.+.}-{0:0}:
       lock_sock_nested net/core/sock.c:3702 [inline]
       lock_sock include/net/sock.h:1651 [inline]
       sockopt_lock_sock+0x88/0x148 net/core/sock.c:1148
       do_ip_setsockopt+0x138c/0x32c0 net/ipv4/ip_sockglue.c:1078
       ip_setsockopt+0x80/0x128 net/ipv4/ip_sockglue.c:1417
       udp_setsockopt+0xb8/0xd0 net/ipv4/udp.c:3058
       sock_common_setsockopt+0xb0/0xcc net/core/sock.c:3894
       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

-> #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 kernel/locking/lockdep.c:3909 [inline]
       __lock_acquire+0x17b8/0x32c4 kernel/locking/lockdep.c:5235
       lock_acquire+0x150/0x2e8 kernel/locking/lockdep.c:5866
       __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
       do_ip_setsockopt+0xd5c/0x32c0 net/ipv4/ip_sockglue.c:1077
       ip_setsockopt+0x80/0x128 net/ipv4/ip_sockglue.c:1417
       tcp_setsockopt+0xcc/0xe8 net/ipv4/tcp.c:4077
       sock_common_setsockopt+0xb0/0xcc net/core/sock.c:3894
       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

other info that might help us debug this:

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

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

1 lock held by syz.3.77/7001:
 #0: ffff0000f6370aa8 (&smc->clcsock_release_lock){+.+.}-{4:4}, at: smc_setsockopt+0x170/0xd0c net/smc/af_smc.c:3073

stack backtrace:
CPU: 0 UID: 0 PID: 7001 Comm: syz.3.77 Not tainted 6.15.0-rc2-syzkaller-gc72692105976 #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/0x1028 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
 __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
 do_ip_setsockopt+0xd5c/0x32c0 net/ipv4/ip_sockglue.c:1077
 ip_setsockopt+0x80/0x128 net/ipv4/ip_sockglue.c:1417
 tcp_setsockopt+0xcc/0xe8 net/ipv4/tcp.c:4077
 sock_common_setsockopt+0xb0/0xcc net/core/sock.c:3894
 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