syzbot

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BUG: KMSAN: uninit-value in ipv6_skip_exthdr+0x796/0x900 net/ipv6/exthdrs_core.c:97
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.16.0+ #83
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:53
 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676
 ipv6_skip_exthdr+0x796/0x900 net/ipv6/exthdrs_core.c:97
 is_ineligible net/ipv6/icmp.c:155 [inline]
 icmp6_send+0xec1/0x3460 net/ipv6/icmp.c:498
 icmpv6_send+0xe0/0x110 net/ipv6/ip6_icmp.c:43
 ip6_link_failure+0x8f/0x580 net/ipv6/route.c:2034
 dst_link_failure include/net/dst.h:426 [inline]
 ndisc_error_report+0x101/0x1a0 net/ipv6/ndisc.c:695
 neigh_invalidate+0x385/0x930 net/core/neighbour.c:883
 neigh_timer_handler+0xd85/0x12d0 net/core/neighbour.c:969
 call_timer_fn+0x26a/0x5a0 kernel/time/timer.c:1326
 expire_timers kernel/time/timer.c:1363 [inline]
 __run_timers+0xda7/0x11c0 kernel/time/timer.c:1666
 run_timer_softirq+0x43/0x70 kernel/time/timer.c:1692
 __do_softirq+0x56d/0x93d kernel/softirq.c:285
 invoke_softirq kernel/softirq.c:365 [inline]
 irq_exit+0x202/0x240 kernel/softirq.c:405
 exiting_irq+0xe/0x10 arch/x86/include/asm/apic.h:541
 smp_apic_timer_interrupt+0x64/0x90 arch/x86/kernel/apic/apic.c:1055
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:857
 </IRQ>
RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:55 [inline]
RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:97 [inline]
RIP: 0010:default_idle+0x1fb/0x3c0 arch/x86/kernel/process.c:354
RSP: 0018:ffffffff87c0fd88 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff12
RAX: ffff880203eb5440 RBX: 0000000000000000 RCX: ffff880000000000
RDX: ffff880203ab5440 RSI: aaaaaaaaaaaab000 RDI: ffffea0000000000
RBP: ffffffff87c0fdc0 R08: 0000000001080020 R09: 0000000000000002
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff87c1eb00 R14: ffffffff87c0fe24 R15: ffffffff87c1f418
 arch_cpu_idle+0x20/0x30 arch/x86/kernel/process.c:345
 default_idle_call kernel/sched/idle.c:98 [inline]
 cpuidle_idle_call kernel/sched/idle.c:156 [inline]
 do_idle+0x349/0x790 kernel/sched/idle.c:246
 cpu_startup_entry+0x45/0x50 kernel/sched/idle.c:351
 rest_init+0x1c1/0x1f0 init/main.c:438
 start_kernel+0xf93/0xfb0 init/main.c:719
 x86_64_start_reservations arch/x86/kernel/head64.c:378 [inline]
 x86_64_start_kernel+0x2fa/0x310 arch/x86/kernel/head64.c:359
 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:239

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:293 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:684
 kmsan_memcpy_origins+0x11d/0x170 mm/kmsan/kmsan.c:526
 __msan_memcpy+0x19f/0x1f0 mm/kmsan/kmsan_instr.c:470
 skb_copy_bits+0x63a/0xdb0 net/core/skbuff.c:2046
 __skb_header_pointer include/linux/skbuff.h:3337 [inline]
 skb_header_pointer include/linux/skbuff.h:3346 [inline]
 ipv6_skip_exthdr+0x472/0x900 net/ipv6/exthdrs_core.c:89
 is_ineligible net/ipv6/icmp.c:155 [inline]
 icmp6_send+0xec1/0x3460 net/ipv6/icmp.c:498
 icmpv6_send+0xe0/0x110 net/ipv6/ip6_icmp.c:43
 ip6_link_failure+0x8f/0x580 net/ipv6/route.c:2034
 dst_link_failure include/net/dst.h:426 [inline]
 ndisc_error_report+0x101/0x1a0 net/ipv6/ndisc.c:695
 neigh_invalidate+0x385/0x930 net/core/neighbour.c:883
 neigh_timer_handler+0xd85/0x12d0 net/core/neighbour.c:969
 call_timer_fn+0x26a/0x5a0 kernel/time/timer.c:1326
 expire_timers kernel/time/timer.c:1363 [inline]
 __run_timers+0xda7/0x11c0 kernel/time/timer.c:1666
 run_timer_softirq+0x43/0x70 kernel/time/timer.c:1692
 __do_softirq+0x56d/0x93d kernel/softirq.c:285
Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_alloc_meta_for_pages+0x161/0x3a0 mm/kmsan/kmsan.c:814
 kmsan_alloc_page+0x82/0xe0 mm/kmsan/kmsan.c:868
 __alloc_pages_nodemask+0xf5b/0x5dc0 mm/page_alloc.c:4283
 alloc_pages_current+0x6b5/0x970 mm/mempolicy.c:2055
 alloc_pages include/linux/gfp.h:494 [inline]
 skb_page_frag_refill+0x3ba/0x5e0 net/core/sock.c:2208
 sk_page_frag_refill+0xa4/0x340 net/core/sock.c:2228
 __ip6_append_data+0x1a20/0x4bb0 net/ipv6/ip6_output.c:1503
 ip6_append_data+0x40e/0x6b0 net/ipv6/ip6_output.c:1576
 rawv6_sendmsg+0x2787/0x4cc0 net/ipv6/raw.c:928
 inet_sendmsg+0x48d/0x740 net/ipv4/af_inet.c:764
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg net/socket.c:640 [inline]
 sock_write_iter+0x3b9/0x470 net/socket.c:909
 call_write_iter include/linux/fs.h:1782 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x719/0x910 fs/read_write.c:482
 vfs_write+0x463/0x8d0 fs/read_write.c:544
 SYSC_write+0x172/0x360 fs/read_write.c:589
 SyS_write+0x55/0x80 fs/read_write.c:581
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
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