====================================================== WARNING: possible circular locking dependency detected 6.15.0-rc2-syzkaller-00037-g834a4a689699 #0 Not tainted ------------------------------------------------------ syz.5.3795/20273 is trying to acquire lock: ffffffff900fd588 (rtnl_mutex){+.+.}-{4:4}, at: do_ip_setsockopt+0x10f0/0x39c0 net/ipv4/ip_sockglue.c:1077 but task is already holding lock: ffff8880297af228 (&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] __ia32_sys_sendto+0xdd/0x100 net/socket.c:2183 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xb4/0x110 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #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:3702 lock_sock include/net/sock.h:1651 [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:3836 __rtnl_newlink net/core/rtnetlink.c:3953 [inline] rtnl_newlink+0x18b0/0x1fe0 net/core/rtnetlink.c:4068 rtnetlink_rcv_msg+0x80f/0xd70 net/core/rtnetlink.c:6958 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_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xb4/0x110 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #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_ip_setsockopt+0x10f0/0x39c0 net/ipv4/ip_sockglue.c:1077 ip_setsockopt+0x63/0x100 net/ipv4/ip_sockglue.c:1417 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] __ia32_sys_setsockopt+0x1f2/0x280 net/socket.c:2324 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xb4/0x110 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e 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.5.3795/20273: #0: ffff8880297af228 (&smc->clcsock_release_lock){+.+.}-{4:4}, at: smc_setsockopt+0x1b2/0xd50 net/smc/af_smc.c:3073 stack backtrace: CPU: 1 UID: 0 PID: 20273 Comm: syz.5.3795 Not tainted 6.15.0-rc2-syzkaller-00037-g834a4a689699 #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_ip_setsockopt+0x10f0/0x39c0 net/ipv4/ip_sockglue.c:1077 ip_setsockopt+0x63/0x100 net/ipv4/ip_sockglue.c:1417 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] __ia32_sys_setsockopt+0x1f2/0x280 net/socket.c:2324 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xb4/0x110 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf70ad579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000f507c55c EFLAGS: 00000206 ORIG_RAX: 000000000000016e RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000000000 RDX: 0000000000000029 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 90 nop 33: 90 nop 34: 90 nop 35: 90 nop 36: 90 nop 37: 90 nop 38: 90 nop 39: 90 nop 3a: 90 nop 3b: 90 nop 3c: 90 nop 3d: 90 nop