netlink: 8 bytes leftover after parsing attributes in process `syz.1.77'. ====================================================== WARNING: possible circular locking dependency detected 6.13.0-rc6-syzkaller-00970-g7d0da8f86234 #0 Not tainted ------------------------------------------------------ syz.1.77/6247 is trying to acquire lock: ffff88803004c818 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1624 [inline] ffff88803004c818 (sk_lock-AF_INET){+.+.}-{0:0}, at: gtp_encap_enable_socket+0x2ce/0x5c0 drivers/net/gtp.c:1672 but task is already holding lock: ffffffff8fcb3f48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] ffffffff8fcb3f48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:335 [inline] ffffffff8fcb3f48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xce2/0x2210 net/core/rtnetlink.c:4020 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (rtnl_mutex){+.+.}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735 do_ip_setsockopt+0x127d/0x3cd0 net/ipv4/ip_sockglue.c:1077 ip_setsockopt+0x63/0x100 net/ipv4/ip_sockglue.c:1417 smc_setsockopt+0x275/0xe50 net/smc/af_smc.c:3081 do_sock_setsockopt+0x3af/0x720 net/socket.c:2326 __sys_setsockopt net/socket.c:2351 [inline] __do_sys_setsockopt net/socket.c:2357 [inline] __se_sys_setsockopt net/socket.c:2354 [inline] __x64_sys_setsockopt+0x1ee/0x280 net/socket.c:2354 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 -> #1 (&smc->clcsock_release_lock){+.+.}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735 smc_switch_to_fallback+0x35/0xd90 net/smc/af_smc.c:903 smc_sendmsg+0x11f/0x530 net/smc/af_smc.c:2781 sock_sendmsg_nosec net/socket.c:713 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:728 __sys_sendto+0x363/0x4c0 net/socket.c:2210 __do_sys_sendto net/socket.c:2217 [inline] __se_sys_sendto net/socket.c:2213 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2213 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_INET){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 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:1672 gtp_encap_enable drivers/net/gtp.c:1706 [inline] gtp_newlink+0x59f/0xf60 drivers/net/gtp.c:1509 rtnl_newlink_create+0x2ee/0xa40 net/core/rtnetlink.c:3795 __rtnl_newlink net/core/rtnetlink.c:3906 [inline] rtnl_newlink+0x1c7e/0x2210 net/core/rtnetlink.c:4021 rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6911 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:2596 ___sys_sendmsg net/socket.c:2650 [inline] __sys_sendmsg+0x269/0x350 net/socket.c:2682 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: Chain exists of: sk_lock-AF_INET --> &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_INET); *** DEADLOCK *** 2 locks held by syz.1.77/6247: #0: ffffffff901a90b0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff901a90b0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff901a90b0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x22/0x250 net/core/rtnetlink.c:564 #1: ffffffff8fcb3f48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #1: ffffffff8fcb3f48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:335 [inline] #1: ffffffff8fcb3f48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xce2/0x2210 net/core/rtnetlink.c:4020 stack backtrace: CPU: 0 UID: 0 PID: 6247 Comm: syz.1.77 Not tainted 6.13.0-rc6-syzkaller-00970-g7d0da8f86234 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 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:2074 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 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:1672 gtp_encap_enable drivers/net/gtp.c:1706 [inline] gtp_newlink+0x59f/0xf60 drivers/net/gtp.c:1509 rtnl_newlink_create+0x2ee/0xa40 net/core/rtnetlink.c:3795 __rtnl_newlink net/core/rtnetlink.c:3906 [inline] rtnl_newlink+0x1c7e/0x2210 net/core/rtnetlink.c:4021 rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6911 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:2596 ___sys_sendmsg net/socket.c:2650 [inline] __sys_sendmsg+0x269/0x350 net/socket.c:2682 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: 0033:0x7f80e7f85d29 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:00007f80e8d0a038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f80e8176080 RCX: 00007f80e7f85d29 RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000009 RBP: 00007f80e8001b08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f80e8176080 R15: 00007ffd6e66be38