bisecting fixing commit since 6dd0e32665e591e9debe3edaf73c2f8135bf047e building syzkaller on 3f3c557402456696073f79aafa65b4d7fa2b8794 testing commit 6dd0e32665e591e9debe3edaf73c2f8135bf047e with gcc (GCC) 8.1.0 kernel signature: 72320053b6021ae3fc11d1850140358d7dc0961e584141436777c12fc7c0d495 all runs: crashed: general protection fault in vxlan_fdb_destroy testing current HEAD d18b78abc0c6e7d3119367c931c583e02d466495 testing commit d18b78abc0c6e7d3119367c931c583e02d466495 with gcc (GCC) 8.1.0 kernel signature: 7e3f77f384482656733aa55834b3d22987cec13519df2c692d3746a4812a3288 all runs: crashed: general protection fault in vxlan_fdb_destroy revisions tested: 2, total time: 27m17.88898898s (build: 19m6.102880035s, test: 6m28.573937161s) the crash still happens on HEAD commit msg: Linux 4.19.141 crash: general protection fault in vxlan_fdb_destroy device bridge1 entered promiscuous mode device bridge1 entered promiscuous mode device bridge1 entered promiscuous mode 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 CPU: 0 PID: 7917 Comm: syz-executor.4 Not tainted 4.19.141-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__write_once_size include/linux/compiler.h:220 [inline] RIP: 0010:__hlist_del include/linux/list.h:679 [inline] RIP: 0010:hlist_del_rcu include/linux/rculist.h:457 [inline] RIP: 0010:vxlan_fdb_destroy+0xa0/0x1b0 drivers/net/vxlan.c:788 Code: 00 fc ff df 4c 89 f2 48 c1 ea 03 80 3c 02 00 0f 85 02 01 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 d6 00 00 00 4d 85 e4 4d 89 65 00 74 25 49 8d 7c RSP: 0018:ffff88808e086d28 EFLAGS: 00010a02 RAX: dffffc0000000000 RBX: ffff88808b56d180 RCX: 1ffff11011fb4407 RDX: 1bd5a00000000040 RSI: ffff88808b56d180 RDI: ffff88808fda2038 RBP: ffff88808e086d50 R08: ffff8880a9a5cbd0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: dead000000000200 R14: ffff88808b56d188 R15: 00000000fffffff0 FS: 00007f5d50dba700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fffbdd6bbfc CR3: 000000008b0b5000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __vxlan_dev_create+0x3bb/0x750 drivers/net/vxlan.c:3274 vxlan_newlink+0xa1/0xe0 drivers/net/vxlan.c:3501 rtnl_newlink+0xc7d/0x1320 net/core/rtnetlink.c:3141 rtnetlink_rcv_msg+0x34f/0x8f0 net/core/rtnetlink.c:4778 netlink_rcv_skb+0x13e/0x3d0 net/netlink/af_netlink.c:2455 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:4796 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x443/0x650 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x765/0xc40 net/netlink/af_netlink.c:1909 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xb5/0xf0 net/socket.c:632 kernel_sendmsg+0x26/0x30 net/socket.c:640 sock_no_sendpage+0xfd/0x140 net/core/sock.c:2668 kernel_sendpage+0x60/0xd0 net/socket.c:3378 sock_sendpage+0x6d/0xd0 net/socket.c:847 pipe_to_sendpage+0x212/0x430 fs/splice.c:452 splice_from_pipe_feed fs/splice.c:503 [inline] __splice_from_pipe+0x2cb/0x720 fs/splice.c:627 splice_from_pipe+0xbb/0x120 fs/splice.c:662 generic_splice_sendpage+0x10/0x20 fs/splice.c:833 do_splice_from fs/splice.c:852 [inline] do_splice+0x4fd/0x12d0 fs/splice.c:1154 __do_sys_splice fs/splice.c:1428 [inline] __se_sys_splice fs/splice.c:1408 [inline] __x64_sys_splice+0x248/0x300 fs/splice.c:1408 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c909 Code: 2d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f5d50db9c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 00007f5d50dba6d4 RCX: 000000000045c909 RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 000000000076bfa0 R08: 000000000004ffe2 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000ba4 R14: 00000000004ce772 R15: 000000000076bfac Modules linked in: ---[ end trace 4b72d54d2de552cd ]--- RIP: 0010:__write_once_size include/linux/compiler.h:220 [inline] RIP: 0010:__hlist_del include/linux/list.h:679 [inline] RIP: 0010:hlist_del_rcu include/linux/rculist.h:457 [inline] RIP: 0010:vxlan_fdb_destroy+0xa0/0x1b0 drivers/net/vxlan.c:788 Code: 00 fc ff df 4c 89 f2 48 c1 ea 03 80 3c 02 00 0f 85 02 01 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 d6 00 00 00 4d 85 e4 4d 89 65 00 74 25 49 8d 7c RSP: 0018:ffff88808e086d28 EFLAGS: 00010a02 RAX: dffffc0000000000 RBX: ffff88808b56d180 RCX: 1ffff11011fb4407 RDX: 1bd5a00000000040 RSI: ffff88808b56d180 RDI: ffff88808fda2038 RBP: ffff88808e086d50 R08: ffff8880a9a5cbd0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: dead000000000200 R14: ffff88808b56d188 R15: 00000000fffffff0 FS: 00007f5d50dba700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fffbdd6bbfc CR3: 000000008b0b5000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400