netlink: 36 bytes leftover after parsing attributes in process `syz.3.101'. ====================================================== WARNING: possible circular locking dependency detected 6.13.0-syzkaller-09720-g3924fa995cdf #0 Not tainted ------------------------------------------------------ syz.3.101/6340 is trying to acquire lock: ffff88814e6b1358 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1624 [inline] ffff88814e6b1358 (sk_lock-AF_INET6){+.+.}-{0:0}, at: gtp_encap_enable_socket+0x2ce/0x5c0 drivers/net/gtp.c:1674 but task is already holding lock: ffffffff8fcbf088 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] ffffffff8fcbf088 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:340 [inline] ffffffff8fcbf088 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xce2/0x2210 net/core/rtnetlink.c:4025 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (rtnl_mutex){+.+.}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730 smc_vlan_by_tcpsk+0x399/0x4e0 net/smc/smc_core.c:1908 __smc_connect+0x296/0x1910 net/smc/af_smc.c:1520 smc_connect+0x868/0xde0 net/smc/af_smc.c:1696 __sys_connect_file net/socket.c:2040 [inline] __sys_connect+0x288/0x2d0 net/socket.c:2059 __do_sys_connect net/socket.c:2065 [inline] __se_sys_connect net/socket.c:2062 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:2062 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (sk_lock-AF_INET6){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3163 [inline] check_prevs_add kernel/locking/lockdep.c:3282 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 lock_sock_nested+0x48/0x100 net/core/sock.c:3645 lock_sock include/net/sock.h:1624 [inline] gtp_encap_enable_socket+0x2ce/0x5c0 drivers/net/gtp.c:1674 gtp_encap_enable drivers/net/gtp.c:1718 [inline] gtp_newlink+0x75d/0xf20 drivers/net/gtp.c:1511 rtnl_newlink_create+0x2ee/0xa40 net/core/rtnetlink.c:3800 __rtnl_newlink net/core/rtnetlink.c:3911 [inline] rtnl_newlink+0x1c7e/0x2210 net/core/rtnetlink.c:4026 rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6916 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline] netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1348 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1892 sock_sendmsg_nosec net/socket.c:713 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:728 ____sys_sendmsg+0x52a/0x7e0 net/socket.c:2568 ___sys_sendmsg net/socket.c:2622 [inline] __sys_sendmsg+0x269/0x350 net/socket.c:2654 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rtnl_mutex); lock(sk_lock-AF_INET6); lock(rtnl_mutex); lock(sk_lock-AF_INET6); *** DEADLOCK *** 2 locks held by syz.3.101/6340: #0: ffffffff901b87b0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff901b87b0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff901b87b0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x22/0x250 net/core/rtnetlink.c:569 #1: ffffffff8fcbf088 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #1: ffffffff8fcbf088 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:340 [inline] #1: ffffffff8fcbf088 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xce2/0x2210 net/core/rtnetlink.c:4025 stack backtrace: CPU: 0 UID: 0 PID: 6340 Comm: syz.3.101 Not tainted 6.13.0-syzkaller-09720-g3924fa995cdf #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2076 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2208 check_prev_add kernel/locking/lockdep.c:3163 [inline] check_prevs_add kernel/locking/lockdep.c:3282 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 lock_sock_nested+0x48/0x100 net/core/sock.c:3645 lock_sock include/net/sock.h:1624 [inline] gtp_encap_enable_socket+0x2ce/0x5c0 drivers/net/gtp.c:1674 gtp_encap_enable drivers/net/gtp.c:1718 [inline] gtp_newlink+0x75d/0xf20 drivers/net/gtp.c:1511 rtnl_newlink_create+0x2ee/0xa40 net/core/rtnetlink.c:3800 __rtnl_newlink net/core/rtnetlink.c:3911 [inline] rtnl_newlink+0x1c7e/0x2210 net/core/rtnetlink.c:4026 rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6916 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline] netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1348 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1892 sock_sendmsg_nosec net/socket.c:713 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:728 ____sys_sendmsg+0x52a/0x7e0 net/socket.c:2568 ___sys_sendmsg net/socket.c:2622 [inline] __sys_sendmsg+0x269/0x350 net/socket.c:2654 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fda02f8cde9 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:00007fda03e63038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fda031a5fa0 RCX: 00007fda02f8cde9 RDX: 0000000000000000 RSI: 0000200000000280 RDI: 0000000000000004 RBP: 00007fda0300e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fda031a5fa0 R15: 00007ffe708486a8