bisecting fixing commit since dda0e2920330128e0dbdeb11c8f25031aa40b11c building syzkaller on 5ed396e666c7826bed46f06c4db1409376691fed testing commit dda0e2920330128e0dbdeb11c8f25031aa40b11c with gcc (GCC) 8.4.1 20210217 kernel signature: adf67c5b934889edee651222000cdf80fb599ec3eb03fd12484950db88b82db6 run #0: crashed: WARNING in ip_rt_bug run #1: crashed: WARNING in corrupted run #2: crashed: WARNING in ip_rt_bug run #3: crashed: WARNING in ip_rt_bug run #4: crashed: WARNING in ip_rt_bug run #5: crashed: WARNING in corrupted run #6: crashed: WARNING in ip_rt_bug run #7: crashed: WARNING in corrupted run #8: crashed: WARNING in corrupted run #9: crashed: WARNING in ip_rt_bug run #10: crashed: WARNING in corrupted run #11: crashed: WARNING in ip_rt_bug run #12: crashed: WARNING in ip_rt_bug run #13: crashed: WARNING in corrupted run #14: crashed: WARNING in ip_rt_bug run #15: crashed: WARNING in corrupted run #16: crashed: WARNING in corrupted run #17: crashed: WARNING in ip_rt_bug run #18: crashed: WARNING in ip_rt_bug run #19: crashed: WARNING in ip_rt_bug testing current HEAD 2d19be4653f5e74ed95560b69f94eb6791d49af3 testing commit 2d19be4653f5e74ed95560b69f94eb6791d49af3 with gcc (GCC) 8.4.1 20210217 kernel signature: 952b0e35ee0474d524628e54e289a9762657bb05767d6bffddd328b0f146c874 all runs: crashed: WARNING in ip_rt_bug revisions tested: 2, total time: 25m18.924251663s (build: 17m32.956441975s, test: 6m17.899801943s) the crash still happens on HEAD commit msg: Linux 4.19.177 crash: WARNING in ip_rt_bug batman_adv: batadv0: Interface activated: batadv_slave_1 IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready syz-executor.1 uses obsolete (PF_INET,SOCK_PACKET) ------------[ cut here ]------------ WARNING: CPU: 1 PID: 7238 at net/ipv4/route.c:1240 ip_rt_bug+0x18/0x20 net/ipv4/route.c:1240 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 7238 Comm: syz-executor.1 Not tainted 4.19.177-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x123/0x171 lib/dump_stack.c:118 panic+0x1cd/0x375 kernel/panic.c:186 __warn.cold.8+0x1b/0x36 kernel/panic.c:541 report_bug+0x1a1/0x200 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] fixup_bug arch/x86/kernel/traps.c:173 [inline] do_error_trap+0x200/0x350 arch/x86/kernel/traps.c:296 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1038 RIP: 0010:ip_rt_bug+0x18/0x20 net/ipv4/route.c:1240 Code: 48 8b 45 d8 e9 ed fe ff ff 66 0f 1f 84 00 00 00 00 00 55 48 89 d7 48 89 e5 e8 14 df a2 ff 48 c7 c7 a0 e8 c6 87 e8 91 bb 16 01 <0f> 0b 31 c0 5d c3 66 90 48 b8 00 00 00 00 00 fc ff df 48 89 fa 55 RSP: 0018:ffff8881d686f110 EFLAGS: 00010282 RAX: 0000000000000024 RBX: ffff8881d6db9200 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff876797e0 RDI: ffffffff8a1859a0 RBP: ffff8881d686f110 R08: ffffed103ed25079 R09: ffffed103ed25078 R10: ffffed103ed25078 R11: ffff8881f69283c7 R12: ffff8881e6634140 R13: ffff8881d8ce92c0 R14: ffff8881d6db9258 R15: ffff8881d686f3d4 dst_output include/net/dst.h:455 [inline] ip_local_out+0x74/0x130 net/ipv4/ip_output.c:125 ip_send_skb+0x36/0xa0 net/ipv4/ip_output.c:1447 ip_push_pending_frames+0x4d/0x70 net/ipv4/ip_output.c:1467 icmp_push_reply+0x383/0x610 net/ipv4/icmp.c:398 __icmp_send+0xbcd/0x18e0 net/ipv4/icmp.c:747 icmp_send include/net/icmp.h:47 [inline] ip_options_compile+0xad/0xc0 net/ipv4/ip_options.c:485 ip_rcv_options net/ipv4/ip_input.c:282 [inline] ip_rcv_finish_core.isra.16+0x3b1/0x1830 net/ipv4/ip_input.c:356 ip_rcv_finish+0x104/0x270 net/ipv4/ip_input.c:412 NF_HOOK include/linux/netfilter.h:289 [inline] NF_HOOK include/linux/netfilter.h:283 [inline] ip_rcv+0xcb/0x2e0 net/ipv4/ip_input.c:524 __netif_receive_skb_one_core+0x112/0x1a0 net/core/dev.c:4954 __netif_receive_skb+0x1f/0x1b0 net/core/dev.c:5066 netif_receive_skb_internal+0xca/0x300 net/core/dev.c:5156 netif_receive_skb+0x3b/0x1e0 net/core/dev.c:5213 tun_rx_batched.isra.54+0x4d8/0x9c0 drivers/net/tun.c:1535 tun_get_user+0x266b/0x4890 drivers/net/tun.c:1966 tun_chr_write_iter+0xb7/0x1a0 drivers/net/tun.c:1999 call_write_iter include/linux/fs.h:1821 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x443/0x890 fs/read_write.c:487 vfs_write+0x150/0x4d0 fs/read_write.c:549 ksys_write+0x103/0x260 fs/read_write.c:599 __do_sys_write fs/read_write.c:611 [inline] __se_sys_write fs/read_write.c:608 [inline] __x64_sys_write+0x6e/0xb0 fs/read_write.c:608 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4641a9 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6d42a14198 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000d0d RCX: 00000000004641a9 RDX: 000000000000100c RSI: 0000000020000240 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000053bf00 R13: 00007f6d42a146bc R14: 00000000ffffffff R15: 0000000000000003 Kernel Offset: disabled Rebooting in 86400 seconds..