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BUG: KMSAN: uninit-value in ip6_parse_tlv+0x89e/0xcb0 net/ipv6/exthdrs.c:156
CPU: 1 PID: 11167 Comm: syz-executor.3 Not tainted 5.8.0-rc5-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+0x1df/0x240 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215
 ip6_parse_tlv+0x89e/0xcb0 net/ipv6/exthdrs.c:156
 ipv6_parse_hopopts+0x493/0x7c0 net/ipv6/exthdrs.c:1043
 ip6_rcv_core+0x1b08/0x1ff0 net/ipv6/ip6_input.c:278
 ipv6_rcv+0xe3/0x710 net/ipv6/ip6_input.c:304
 __netif_receive_skb_one_core net/core/dev.c:5281 [inline]
 __netif_receive_skb net/core/dev.c:5395 [inline]
 netif_receive_skb_internal net/core/dev.c:5497 [inline]
 netif_receive_skb+0x6ab/0xff0 net/core/dev.c:5556
 tun_rx_batched include/linux/skbuff.h:4327 [inline]
 tun_get_user+0x6df8/0x72f0 drivers/net/tun.c:1972
 tun_chr_write_iter+0x1f2/0x360 drivers/net/tun.c:2001
 call_write_iter include/linux/fs.h:1908 [inline]
 new_sync_write fs/read_write.c:503 [inline]
 vfs_write+0xd98/0x1480 fs/read_write.c:578
 ksys_write+0x267/0x450 fs/read_write.c:631
 __do_sys_write fs/read_write.c:643 [inline]
 __se_sys_write+0x92/0xb0 fs/read_write.c:640
 __x64_sys_write+0x4a/0x70 fs/read_write.c:640
 do_syscall_64+0xb0/0x150 arch/x86/entry/common.c:386
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c1f9
Code: Bad RIP value.
RSP: 002b:00007ff6ef3abc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000037e40 RCX: 000000000045c1f9
RDX: 0000000000000fca RSI: 0000000020000040 RDI: 0000000000000003
RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 0000000000c9fb6f R14: 00007ff6ef3ac9c0 R15: 000000000078bf0c

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline]
 kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:127
 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:80
 slab_alloc_node mm/slub.c:2839 [inline]
 __kmalloc_node_track_caller+0xb40/0x1200 mm/slub.c:4478
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0x2fd/0xac0 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1083 [inline]
 alloc_skb_with_frags+0x18c/0xa70 net/core/skbuff.c:5770
 sock_alloc_send_pskb+0xada/0xc60 net/core/sock.c:2356
 tun_alloc_skb drivers/net/tun.c:1494 [inline]
 tun_get_user+0x10b7/0x72f0 drivers/net/tun.c:1811
 tun_chr_write_iter+0x1f2/0x360 drivers/net/tun.c:2001
 call_write_iter include/linux/fs.h:1908 [inline]
 new_sync_write fs/read_write.c:503 [inline]
 vfs_write+0xd98/0x1480 fs/read_write.c:578
 ksys_write+0x267/0x450 fs/read_write.c:631
 __do_sys_write fs/read_write.c:643 [inline]
 __se_sys_write+0x92/0xb0 fs/read_write.c:640
 __x64_sys_write+0x4a/0x70 fs/read_write.c:640
 do_syscall_64+0xb0/0x150 arch/x86/entry/common.c:386
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
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