KMSAN: uninit-value in ip6_parse

KMSAN: uninit-value in ip6_parse_tlv
Status: upstream: reported C repro on 2018/09/20 20:54
Reported-by: syzbot+f08ac29f2ac8aea19826@syzkaller.appspotmail.com
First crash: 1096d, last: 4d09h

Sample crash report:

IPVS: ftp: loaded support on port[0] = 21
==================================================================
BUG: KMSAN: uninit-value in ip6_parse_tlv+0x87f/0xc70 net/ipv6/exthdrs.c:159
CPU: 1 PID: 10363 Comm: syz-executor959 Not tainted 5.1.0-rc4+ #1
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+0x173/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x131/0x2a0 mm/kmsan/kmsan.c:619
 __msan_warning+0x7a/0xf0 mm/kmsan/kmsan_instr.c:310
 ip6_parse_tlv+0x87f/0xc70 net/ipv6/exthdrs.c:159
 ipv6_destopt_rcv+0x5c1/0xdd0 net/ipv6/exthdrs.c:311
 ip6_protocol_deliver_rcu+0xb5a/0x23a0 net/ipv6/ip6_input.c:394
 ip6_input_finish net/ipv6/ip6_input.c:434 [inline]
 NF_HOOK include/linux/netfilter.h:289 [inline]
 ip6_input+0x2b6/0x350 net/ipv6/ip6_input.c:443
 dst_input include/net/dst.h:450 [inline]
 ip6_rcv_finish+0x4de/0x6d0 net/ipv6/ip6_input.c:76
 NF_HOOK include/linux/netfilter.h:289 [inline]
 ipv6_rcv+0x34b/0x3f0 net/ipv6/ip6_input.c:272
 __netif_receive_skb_one_core net/core/dev.c:4973 [inline]
 __netif_receive_skb net/core/dev.c:5085 [inline]
 netif_receive_skb_internal+0x5cd/0x9a0 net/core/dev.c:5188
 napi_frags_finish net/core/dev.c:5755 [inline]
 napi_gro_frags+0x1737/0x2950 net/core/dev.c:5829
 tun_get_user+0x55d7/0x6e30 drivers/net/tun.c:1981
 tun_chr_write_iter+0x1f2/0x360 drivers/net/tun.c:2027
 do_iter_readv_writev+0x9b3/0xbd0 include/linux/fs.h:1860
 do_iter_write+0x304/0xdc0 fs/read_write.c:957
 vfs_writev fs/read_write.c:1002 [inline]
 do_writev+0x3f8/0x900 fs/read_write.c:1037
 __do_sys_writev fs/read_write.c:1110 [inline]
 __se_sys_writev+0x9b/0xb0 fs/read_write.c:1107
 __x64_sys_writev+0x4a/0x70 fs/read_write.c:1107
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x4414d0
Code: 05 48 3d 01 f0 ff ff 0f 83 3d 0f fc ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 83 3d 41 9b 29 00 00 75 14 b8 14 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 14 0f fc ff c3 48 83 ec 08 e8 7a 2b 00 00
RSP: 002b:00007ffc0c854408 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007ffc0c854420 RCX: 00000000004414d0
RDX: 0000000000000001 RSI: 00007ffc0c854440 RDI: 00000000000000f0
RBP: 00007ffc0c854410 R08: 0000000000000100 R09: 00000000bb1414ac
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007ffc0c854418 R14: 0000000000000000 R15: 0000000000000000

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:205 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:220 [inline]
 kmsan_internal_chain_origin+0x134/0x230 mm/kmsan/kmsan.c:426
 kmsan_memcpy_memmove_metadata+0x989/0xd60 mm/kmsan/kmsan.c:304
 kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:324
 __msan_memcpy+0x58/0x70 mm/kmsan/kmsan_instr.c:139
 pskb_expand_head+0x3aa/0x1a30 net/core/skbuff.c:1478
 skb_unclone include/linux/skbuff.h:1571 [inline]
 inet_frag_reasm_prepare+0xdbe/0x1410 net/ipv4/inet_fragment.c:389
 nf_ct_frag6_reasm net/ipv6/netfilter/nf_conntrack_reasm.c:331 [inline]
 nf_ct_frag6_queue net/ipv6/netfilter/nf_conntrack_reasm.c:294 [inline]
 nf_ct_frag6_gather+0x25f2/0x3550 net/ipv6/netfilter/nf_conntrack_reasm.c:477
 ipv6_defrag+0x542/0x650 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:69
 nf_hook_entry_hookfn include/linux/netfilter.h:119 [inline]
 nf_hook_slow+0x176/0x3d0 net/netfilter/core.c:511
 nf_hook include/linux/netfilter.h:244 [inline]
 NF_HOOK include/linux/netfilter.h:287 [inline]
 ipv6_rcv+0x26b/0x3f0 net/ipv6/ip6_input.c:272
 __netif_receive_skb_one_core net/core/dev.c:4973 [inline]
 __netif_receive_skb net/core/dev.c:5085 [inline]
 netif_receive_skb_internal+0x5cd/0x9a0 net/core/dev.c:5188
 napi_frags_finish net/core/dev.c:5755 [inline]
 napi_gro_frags+0x1737/0x2950 net/core/dev.c:5829
 tun_get_user+0x55d7/0x6e30 drivers/net/tun.c:1981
 tun_chr_write_iter+0x1f2/0x360 drivers/net/tun.c:2027
 do_iter_readv_writev+0x9b3/0xbd0 include/linux/fs.h:1860
 do_iter_write+0x304/0xdc0 fs/read_write.c:957
 vfs_writev fs/read_write.c:1002 [inline]
 do_writev+0x3f8/0x900 fs/read_write.c:1037
 __do_sys_writev fs/read_write.c:1110 [inline]
 __se_sys_writev+0x9b/0xb0 fs/read_write.c:1107
 __x64_sys_writev+0x4a/0x70 fs/read_write.c:1107
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7

Uninit was created at:
 kmsan_save_stack_with_flags+0x7a/0x130 mm/kmsan/kmsan.c:205
 kmsan_internal_alloc_meta_for_pages+0x112/0x500 mm/kmsan/kmsan_hooks.c:99
 kmsan_alloc_page+0x7e/0x100 mm/kmsan/kmsan_hooks.c:243
 __alloc_pages_nodemask+0x12fb/0x5e90 mm/page_alloc.c:4644
 __alloc_pages include/linux/gfp.h:475 [inline]
 __alloc_pages_node include/linux/gfp.h:488 [inline]
 alloc_pages_node include/linux/gfp.h:502 [inline]
 __page_frag_cache_refill mm/page_alloc.c:4719 [inline]
 page_frag_alloc+0x3cb/0x900 mm/page_alloc.c:4749
 __napi_alloc_skb+0x194/0x980 net/core/skbuff.c:485
 napi_alloc_skb include/linux/skbuff.h:2785 [inline]
 page_to_skb+0x15c/0x1250 drivers/net/virtio_net.c:397
 receive_mergeable drivers/net/virtio_net.c:937 [inline]
 receive_buf+0x10a1/0x8e30 drivers/net/virtio_net.c:1046
 virtnet_receive drivers/net/virtio_net.c:1336 [inline]
 virtnet_poll+0x916/0x1a20 drivers/net/virtio_net.c:1441
 napi_poll net/core/dev.c:6348 [inline]
 net_rx_action+0x78b/0x1a60 net/core/dev.c:6414
 __do_softirq+0x53f/0x93a kernel/softirq.c:294
==================================================================

Crashes (434):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci-upstream-kmsan-gce	2019/04/23 01:38	https://github.com/google/kmsan.git master	199a02db	53199d6e	.config	log	report	syz	C
ci-upstream-kmsan-gce	2019/02/06 04:05	https://github.com/google/kmsan.git master	fa1981be	d672172c	.config	log	report	syz	C
ci-upstream-kmsan-gce	2018/05/10 06:35	https://github.com/google/kmsan.git master	74ee2200	12c7428a	.config	log	report	syz	C
ci-upstream-kmsan-gce	2021/04/10 22:16	https://github.com/google/kmsan.git master	4ebaab5f	bfeda1b1	.config	log	report			info	KMSAN: uninit-value in ip6_parse_tlv
ci-upstream-kmsan-gce	2021/04/02 20:17	https://github.com/google/kmsan.git master	29ad81a1	6a81331a	.config	log	report			info	KMSAN: uninit-value in ip6_parse_tlv
ci-upstream-kmsan-gce-386	2021/03/27 13:36	https://github.com/google/kmsan.git master	29ad81a1	a8529b82	.config	log	report			info	KMSAN: uninit-value in ip6_parse_tlv
ci-upstream-kmsan-gce-386	2021/03/23 03:46	https://github.com/google/kmsan.git master	29ad81a1	8092f30d	.config	log	report			info	KMSAN: uninit-value in ip6_parse_tlv
ci-upstream-kmsan-gce-386	2021/02/08 07:27	https://github.com/google/kmsan.git master	73d62e81	2ce644fc	.config	log	report			info	KMSAN: uninit-value in ip6_parse_tlv
ci-upstream-kmsan-gce	2021/01/03 23:36	https://github.com/google/kmsan.git master	73d62e81	79264ae3	.config	log	report			info
ci-upstream-kmsan-gce	2020/10/07 08:43	https://github.com/google/kmsan.git master	5edb1df2	1880b4a9	.config	log	report			info
ci-upstream-kmsan-gce	2020/10/07 05:48	https://github.com/google/kmsan.git master	5edb1df2	1880b4a9	.config	log	report			info
ci-upstream-kmsan-gce	2020/10/06 09:09	https://github.com/google/kmsan.git master	5edb1df2	1880b4a9	.config	log	report			info
ci-upstream-kmsan-gce	2020/10/01 08:23	https://github.com/google/kmsan.git master	5edb1df2	a9767fb2	.config	log	report			info
ci-upstream-kmsan-gce	2020/08/24 17:11	https://github.com/google/kmsan.git master	ce8056d1	67b599d1	.config	log	report
ci-upstream-kmsan-gce	2020/08/23 06:00	https://github.com/google/kmsan.git master	ce8056d1	1da71ab0	.config	log	report
ci-upstream-kmsan-gce	2020/08/22 15:07	https://github.com/google/kmsan.git master	ce8056d1	6436ce4b	.config	log	report
ci-upstream-kmsan-gce	2020/08/17 18:35	https://github.com/google/kmsan.git master	ce8056d1	424dd8e7	.config	log	report
ci-upstream-kmsan-gce	2020/08/15 19:20	https://github.com/google/kmsan.git master	ce8056d1	424dd8e7	.config	log	report
ci-upstream-kmsan-gce	2020/07/26 08:14	https://github.com/google/kmsan.git master	93f54a72	1f7cc1ca	.config	log	report
ci-upstream-kmsan-gce	2020/07/26 03:42	https://github.com/google/kmsan.git master	93f54a72	1f7cc1ca	.config	log	report
ci-upstream-kmsan-gce	2020/07/23 15:27	https://github.com/google/kmsan.git master	93f54a72	340ea530	.config	log	report
ci-upstream-kmsan-gce	2020/07/14 23:29	https://github.com/google/kmsan.git master	f0d5ec90	609fb517	.config	log	report
ci-upstream-kmsan-gce	2020/07/14 01:13	https://github.com/google/kmsan.git master	f0d5ec90	f90ec899	.config	log	report
ci-upstream-kmsan-gce	2020/07/13 05:02	https://github.com/google/kmsan.git master	f0d5ec90	9ebcc5b1	.config	log	report
ci-upstream-kmsan-gce	2020/07/12 17:41	https://github.com/google/kmsan.git master	f0d5ec90	115e1930	.config	log	report
ci-upstream-kmsan-gce	2020/07/09 05:31	https://github.com/google/kmsan.git master	f0d5ec90	bc238812	.config	log	report
ci-upstream-kmsan-gce	2020/07/08 17:52	https://github.com/google/kmsan.git master	f0d5ec90	51095195	.config	log	report
ci-upstream-kmsan-gce	2020/07/08 03:04	https://github.com/google/kmsan.git master	f0d5ec90	51095195	.config	log	report
ci-upstream-kmsan-gce	2020/07/04 14:02	https://github.com/google/kmsan.git master	f0d5ec90	51095195	.config	log	report
ci-upstream-kmsan-gce	2020/07/03 07:16	https://github.com/google/kmsan.git master	f0d5ec90	bed10395	.config	log	report
ci-upstream-kmsan-gce	2020/06/29 09:09	https://github.com/google/kmsan.git master	f0d5ec90	a2cdad9d	.config	log	report
ci-upstream-kmsan-gce	2020/06/27 23:56	https://github.com/google/kmsan.git master	f0d5ec90	ffec44b5	.config	log	report
ci-upstream-kmsan-gce	2020/06/25 14:52	https://github.com/google/kmsan.git master	f0d5ec90	54566aff	.config	log	report
ci-upstream-kmsan-gce	2020/06/24 11:39	https://github.com/google/kmsan.git master	f0d5ec90	54566aff	.config	log	report
ci-upstream-kmsan-gce	2020/06/21 07:25	https://github.com/google/kmsan.git master	f0d5ec90	c655ec77	.config	log	report
ci-upstream-kmsan-gce	2020/06/20 04:19	https://github.com/google/kmsan.git master	f0d5ec90	81abc331	.config	log	report
ci-upstream-kmsan-gce	2020/06/18 00:53	https://github.com/google/kmsan.git master	f0d5ec90	b9f3810b	.config	log	report
ci-upstream-kmsan-gce	2020/06/17 11:26	https://github.com/google/kmsan.git master	f0d5ec90	b9f3810b	.config	log	report
ci-upstream-kmsan-gce	2020/06/14 12:22	https://github.com/google/kmsan.git master	f0d5ec90	2a22c77a	.config	log	report
ci-upstream-kmsan-gce	2020/06/10 12:58	https://github.com/google/kmsan.git master	f0d5ec90	860c4de9	.config	log	report
ci-upstream-kmsan-gce	2020/06/10 02:37	https://github.com/google/kmsan.git master	f0d5ec90	860c4de9	.config	log	report
ci-upstream-kmsan-gce	2018/04/14 11:38	https://github.com/google/kmsan.git master	35ff515e	7a67784c	.config	log	report
ci-upstream-kmsan-gce-386	2020/12/22 18:44	https://github.com/google/kmsan.git master	73d62e81	04201c06	.config	log	report			info
ci-upstream-kmsan-gce-386	2020/12/12 15:27	https://github.com/google/kmsan.git master	73d62e81	bca53db9	.config	log	report			info
ci-upstream-kmsan-gce-386	2020/11/01 01:39	https://github.com/google/kmsan.git master	e1617422	8bc4594f	.config	log	report			info
ci-upstream-kmsan-gce-386	2020/10/01 10:57	https://github.com/google/kmsan.git master	5edb1df2	a9767fb2	.config	log	report			info
ci-upstream-kmsan-gce-386	2020/09/04 03:20	https://github.com/google/kmsan.git master	3b3ea602	abf9ba4f	.config	log	report
ci-upstream-kmsan-gce-386	2020/09/01 16:39	https://github.com/google/kmsan.git master	3b3ea602	d5a3ae1f	.config	log	report
ci-upstream-kmsan-gce-386	2020/08/05 01:20	https://github.com/google/kmsan.git master	93f54a72	80a06902	.config	log	report
ci-upstream-kmsan-gce-386	2020/07/28 01:52	https://github.com/google/kmsan.git master	93f54a72	cb93dc6a	.config	log	report