================================================================== BUG: KMSAN: uninit-value in ipv6_ext_hdr net/ipv6/exthdrs_core.c:17 [inline] BUG: KMSAN: uninit-value in ipv6_skip_exthdr+0x156/0x910 net/ipv6/exthdrs_core.c:78 CPU: 0 PID: 8989 Comm: syz-executor3 Not tainted 4.18.0-rc4+ #23 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+0x185/0x1e0 lib/dump_stack.c:113 kmsan_report+0x195/0x2c0 mm/kmsan/kmsan.c:990 __msan_warning_32+0x7d/0xe0 mm/kmsan/kmsan_instr.c:640 ipv6_ext_hdr net/ipv6/exthdrs_core.c:17 [inline] ipv6_skip_exthdr+0x156/0x910 net/ipv6/exthdrs_core.c:78 ipv6_get_l4proto+0x1be/0x2f0 net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c:83 nf_conntrack_in+0x54a/0x2070 net/netfilter/nf_conntrack_core.c:1388 ipv6_conntrack_in+0xc3/0xf0 net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c:172 nf_hook_entry_hookfn include/linux/netfilter.h:119 [inline] nf_hook_slow+0x15d/0x3e0 net/netfilter/core.c:511 nf_hook include/linux/netfilter.h:242 [inline] NF_HOOK include/linux/netfilter.h:285 [inline] ipv6_rcv+0x1df5/0x2250 net/ipv6/ip6_input.c:208 __netif_receive_skb_core+0x4a7a/0x4fc0 net/core/dev.c:4628 __netif_receive_skb net/core/dev.c:4693 [inline] netif_receive_skb_internal+0x475/0x660 net/core/dev.c:4767 netif_receive_skb+0x246/0x270 net/core/dev.c:4791 tun_rx_batched drivers/net/tun.c:1571 [inline] tun_get_user+0x80f6/0x89c0 drivers/net/tun.c:1981 tun_chr_write_iter+0x1d4/0x330 drivers/net/tun.c:2009 do_iter_readv_writev+0x81a/0xac0 include/linux/fs.h:1787 do_iter_write+0x30d/0xd50 fs/read_write.c:959 vfs_writev fs/read_write.c:1004 [inline] do_writev+0x3d8/0x860 fs/read_write.c:1039 __do_sys_writev fs/read_write.c:1112 [inline] __se_sys_writev fs/read_write.c:1109 [inline] __x64_sys_writev+0xe1/0x120 fs/read_write.c:1109 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x63/0xe7 RIP: 0033:0x455ce1 Code: 75 14 b8 14 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 54 bb fb ff c3 48 83 ec 08 e8 da 2c 00 00 48 89 04 24 b8 14 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 23 2d 00 00 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007f8c71410ba0 EFLAGS: 00000293 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 0000000000000046 RCX: 0000000000455ce1 RDX: 0000000000000001 RSI: 00007f8c71410bf0 RDI: 00000000000000fc RBP: 0000000020000700 R08: 00000000000000fc R09: 0000000000000000 R10: 0000000000000046 R11: 0000000000000293 R12: 00000000ffffffff R13: 00000000004c2440 R14: 00000000004d3ca0 R15: 0000000000000000 Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:256 [inline] kmsan_save_stack mm/kmsan/kmsan.c:271 [inline] kmsan_internal_chain_origin+0x13c/0x240 mm/kmsan/kmsan.c:581 kmsan_memcpy_origins+0x11d/0x170 mm/kmsan/kmsan.c:425 __msan_memcpy+0xe7/0x150 mm/kmsan/kmsan_instr.c:432 skb_copy_from_linear_data_offset include/linux/skbuff.h:3385 [inline] skb_copy_bits+0x1f9/0xd80 net/core/skbuff.c:2038 ipv6_get_l4proto+0x105/0x2f0 net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c:78 nf_conntrack_in+0x54a/0x2070 net/netfilter/nf_conntrack_core.c:1388 ipv6_conntrack_in+0xc3/0xf0 net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c:172 nf_hook_entry_hookfn include/linux/netfilter.h:119 [inline] nf_hook_slow+0x15d/0x3e0 net/netfilter/core.c:511 nf_hook include/linux/netfilter.h:242 [inline] NF_HOOK include/linux/netfilter.h:285 [inline] ipv6_rcv+0x1df5/0x2250 net/ipv6/ip6_input.c:208 __netif_receive_skb_core+0x4a7a/0x4fc0 net/core/dev.c:4628 __netif_receive_skb net/core/dev.c:4693 [inline] netif_receive_skb_internal+0x475/0x660 net/core/dev.c:4767 netif_receive_skb+0x246/0x270 net/core/dev.c:4791 tun_rx_batched drivers/net/tun.c:1571 [inline] tun_get_user+0x80f6/0x89c0 drivers/net/tun.c:1981 tun_chr_write_iter+0x1d4/0x330 drivers/net/tun.c:2009 do_iter_readv_writev+0x81a/0xac0 include/linux/fs.h:1787 do_iter_write+0x30d/0xd50 fs/read_write.c:959 vfs_writev fs/read_write.c:1004 [inline] do_writev+0x3d8/0x860 fs/read_write.c:1039 __do_sys_writev fs/read_write.c:1112 [inline] __se_sys_writev fs/read_write.c:1109 [inline] __x64_sys_writev+0xe1/0x120 fs/read_write.c:1109 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x63/0xe7 Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:256 [inline] kmsan_save_stack mm/kmsan/kmsan.c:271 [inline] kmsan_internal_chain_origin+0x13c/0x240 mm/kmsan/kmsan.c:581 kmsan_memcpy_origins+0x11d/0x170 mm/kmsan/kmsan.c:425 kmsan_memmove_origins+0x9/0x10 mm/kmsan/kmsan.c:480 __msan_memmove+0xe7/0x150 mm/kmsan/kmsan_instr.c:381 nf_ct_frag6_reasm net/ipv6/netfilter/nf_conntrack_reasm.c:432 [inline] nf_ct_frag6_gather+0x436a/0x5870 net/ipv6/netfilter/nf_conntrack_reasm.c:586 ipv6_defrag+0x501/0x5c0 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:71 nf_hook_entry_hookfn include/linux/netfilter.h:119 [inline] nf_hook_slow+0x15d/0x3e0 net/netfilter/core.c:511 nf_hook include/linux/netfilter.h:242 [inline] NF_HOOK include/linux/netfilter.h:285 [inline] ipv6_rcv+0x1df5/0x2250 net/ipv6/ip6_input.c:208 __netif_receive_skb_core+0x4a7a/0x4fc0 net/core/dev.c:4628 __netif_receive_skb net/core/dev.c:4693 [inline] netif_receive_skb_internal+0x475/0x660 net/core/dev.c:4767 netif_receive_skb+0x246/0x270 net/core/dev.c:4791 tun_rx_batched drivers/net/tun.c:1571 [inline] tun_get_user+0x80f6/0x89c0 drivers/net/tun.c:1981 tun_chr_write_iter+0x1d4/0x330 drivers/net/tun.c:2009 do_iter_readv_writev+0x81a/0xac0 include/linux/fs.h:1787 do_iter_write+0x30d/0xd50 fs/read_write.c:959 vfs_writev fs/read_write.c:1004 [inline] do_writev+0x3d8/0x860 fs/read_write.c:1039 __do_sys_writev fs/read_write.c:1112 [inline] __se_sys_writev fs/read_write.c:1109 [inline] __x64_sys_writev+0xe1/0x120 fs/read_write.c:1109 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x63/0xe7 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:256 [inline] kmsan_internal_alloc_meta_for_pages+0x157/0x730 mm/kmsan/kmsan.c:702 kmsan_alloc_page+0x80/0xe0 mm/kmsan/kmsan_hooks.c:250 __alloc_pages_nodemask+0x105b/0x6320 mm/page_alloc.c:4409 alloc_pages_current+0x6b1/0x970 mm/mempolicy.c:2093 alloc_pages include/linux/gfp.h:494 [inline] skb_page_frag_refill+0x3be/0x5f0 net/core/sock.c:2218 tun_build_skb drivers/net/tun.c:1642 [inline] tun_get_user+0xede/0x89c0 drivers/net/tun.c:1817 tun_chr_write_iter+0x1d4/0x330 drivers/net/tun.c:2009 do_iter_readv_writev+0x81a/0xac0 include/linux/fs.h:1787 do_iter_write+0x30d/0xd50 fs/read_write.c:959 vfs_writev fs/read_write.c:1004 [inline] do_writev+0x3d8/0x860 fs/read_write.c:1039 __do_sys_writev fs/read_write.c:1112 [inline] __se_sys_writev fs/read_write.c:1109 [inline] __x64_sys_writev+0xe1/0x120 fs/read_write.c:1109 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x63/0xe7 ==================================================================