====================================================== WARNING: possible circular locking dependency detected 6.14.0-syzkaller-13305-g61f96e684edd #0 Not tainted ------------------------------------------------------ syz.0.365/7420 is trying to acquire lock: ffffffff900fc9c8 (rtnl_mutex){+.+.}-{4:4}, at: do_ipv6_setsockopt+0xa9a/0x3680 net/ipv6/ipv6_sockglue.c:566 but task is already holding lock: ffff888078262d20 (&smc->clcsock_release_lock){+.+.}-{4:4}, at: smc_setsockopt+0x1b2/0xd50 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}: 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_sendmsg+0x11f/0x530 net/smc/af_smc.c:2781 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:727 __sys_sendto+0x365/0x4c0 net/socket.c:2180 __do_sys_sendto net/socket.c:2187 [inline] __se_sys_sendto net/socket.c:2183 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2183 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_INET){+.+.}-{0:0}: lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 lock_sock_nested+0x48/0x100 net/core/sock.c:3697 lock_sock include/net/sock.h:1615 [inline] gtp_encap_enable_socket+0x306/0x630 drivers/net/gtp.c:1676 gtp_encap_enable drivers/net/gtp.c:1710 [inline] gtp_newlink+0x605/0xf80 drivers/net/gtp.c:1513 rtnl_newlink_create+0x39b/0xcb0 net/core/rtnetlink.c:3833 __rtnl_newlink net/core/rtnetlink.c:3950 [inline] rtnl_newlink+0x18b0/0x1fe0 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x80f/0xd70 net/core/rtnetlink.c:6955 netlink_rcv_skb+0x208/0x480 net/netlink/af_netlink.c:2534 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x7f8/0x9a0 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x8c3/0xcd0 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:727 ____sys_sendmsg+0x523/0x860 net/socket.c:2566 ___sys_sendmsg net/socket.c:2620 [inline] __sys_sendmsg+0x271/0x360 net/socket.c:2652 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 do_ipv6_setsockopt+0xa9a/0x3680 net/ipv6/ipv6_sockglue.c:566 ipv6_setsockopt+0x5d/0x170 net/ipv6/ipv6_sockglue.c:993 smc_setsockopt+0x25c/0xd50 net/smc/af_smc.c:3081 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 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.0.365/7420: #0: ffff888078262d20 (&smc->clcsock_release_lock){+.+.}-{4:4}, at: smc_setsockopt+0x1b2/0xd50 net/smc/af_smc.c:3073 stack backtrace: CPU: 1 UID: 0 PID: 7420 Comm: syz.0.365 Not tainted 6.14.0-syzkaller-13305-g61f96e684edd #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __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 do_ipv6_setsockopt+0xa9a/0x3680 net/ipv6/ipv6_sockglue.c:566 ipv6_setsockopt+0x5d/0x170 net/ipv6/ipv6_sockglue.c:993 smc_setsockopt+0x25c/0xd50 net/smc/af_smc.c:3081 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 RIP: 0033:0x7fb67fb8d169 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:00007fb68098d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007fb67fda6240 RCX: 00007fb67fb8d169 RDX: 000000000000002d RSI: 0000000000000029 RDI: 0000000000000004 RBP: 00007fb67fc0e2a0 R08: 0000000000000088 R09: 0000000000000000 R10: 0000200000000100 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fb67fda6240 R15: 00007ffdf0d55028