bisecting fixing commit since 69b94dd6dcd14d9bfcba35a492f5e27c15cf4d0a building syzkaller on 70c104a18f3d409bc6dde950b50258d3d280d99b testing commit 69b94dd6dcd14d9bfcba35a492f5e27c15cf4d0a with gcc (GCC) 8.4.1 20210217 kernel signature: 7a617b4445ea836206bb7559dfa898ad600d7920be7315474b16c6dc7170bee7 all runs: crashed: general protection fault in vxlan_fdb_destroy testing current HEAD cf256fbcbe347b7d0ff58fe2dfa382a156bd3694 testing commit cf256fbcbe347b7d0ff58fe2dfa382a156bd3694 with gcc (GCC) 8.4.1 20210217 kernel signature: e78c8169a7fcb0b0d992159b2b4269257159331d35843697006be03cc0f3d18b all runs: crashed: general protection fault in vxlan_fdb_destroy revisions tested: 2, total time: 23m14.350546572s (build: 16m14.914464843s, test: 6m31.861625119s) the crash still happens on HEAD commit msg: Linux 4.14.231 crash: general protection fault in vxlan_fdb_destroy device veth1_vlan entered promiscuous mode IPv6: ADDRCONF(NETDEV_UP): macvlan0: link is not ready netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'. kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN Modules linked in: CPU: 1 PID: 7069 Comm: syz-executor.0 Not tainted 4.14.231-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8881d9e56200 task.stack: ffff8881da6e0000 RIP: 0010:__write_once_size include/linux/compiler.h:210 [inline] RIP: 0010:__hlist_del include/linux/list.h:679 [inline] RIP: 0010:hlist_del_rcu include/linux/rculist.h:427 [inline] RIP: 0010:vxlan_fdb_destroy+0x9e/0x180 drivers/net/vxlan.c:787 RSP: 0018:ffff8881da6e6f88 EFLAGS: 00010a02 RAX: dffffc0000000000 RBX: ffff8881ede2e580 RCX: 1ffff1103b42ab00 RDX: 1bd5a00000000040 RSI: ffff8881ede2e580 RDI: ffff8881ede2e588 RBP: ffff8881da6e6fa8 R08: ffff8881d9e56ad0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: dead000000000200 R14: ffff8881da6e7078 R15: 00000000fffffff0 FS: 00007fe00ad00700(0000) GS:ffff8881f6700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe00ad00718 CR3: 00000001dabde004 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __vxlan_dev_create+0x3a9/0x740 drivers/net/vxlan.c:3281 vxlan_newlink+0x99/0xd0 drivers/net/vxlan.c:3502 rtnl_newlink+0xcc9/0x1630 net/core/rtnetlink.c:2728 rtnetlink_rcv_msg+0x34c/0x9e0 net/core/rtnetlink.c:4316 netlink_rcv_skb+0x12f/0x3b0 net/netlink/af_netlink.c:2433 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:4328 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline] netlink_unicast+0x40b/0x610 net/netlink/af_netlink.c:1313 netlink_sendmsg+0x639/0xbe0 net/netlink/af_netlink.c:1878 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xac/0xf0 net/socket.c:656 kernel_sendmsg+0x26/0x30 net/socket.c:664 sock_no_sendpage+0xf7/0x130 net/core/sock.c:2595 kernel_sendpage+0x60/0xd0 net/socket.c:3407 sock_sendpage+0x6d/0xd0 net/socket.c:871 pipe_to_sendpage+0x206/0x420 fs/splice.c:451 splice_from_pipe_feed fs/splice.c:502 [inline] __splice_from_pipe+0x2cb/0x720 fs/splice.c:626 splice_from_pipe+0xb5/0x110 fs/splice.c:661 generic_splice_sendpage+0x10/0x20 fs/splice.c:832 do_splice_from fs/splice.c:851 [inline] do_splice fs/splice.c:1147 [inline] SYSC_splice fs/splice.c:1402 [inline] SyS_splice+0x6f1/0x1590 fs/splice.c:1382 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x463b49 RSP: 002b:00007fe00ad00188 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 000000000055c040 RCX: 0000000000463b49 RDX: 0000000000000008 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 00000000004ae538 R08: 000000000004ffe2 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055c040 R13: 00007ffc7581a22f R14: 00007fe00ad00300 R15: 0000000000022000 Code: 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 d8 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 6b 08 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 ac 00 00 00 4d 85 e4 4d 89 65 00 74 25 49 8d RIP: __write_once_size include/linux/compiler.h:210 [inline] RSP: ffff8881da6e6f88 RIP: __hlist_del include/linux/list.h:679 [inline] RSP: ffff8881da6e6f88 RIP: hlist_del_rcu include/linux/rculist.h:427 [inline] RSP: ffff8881da6e6f88 RIP: vxlan_fdb_destroy+0x9e/0x180 drivers/net/vxlan.c:787 RSP: ffff8881da6e6f88 ---[ end trace 55ceece0fa5ed5e6 ]---