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BUG: KMSAN: uninit-value in _decode_session6+0x635/0x1630 net/ipv6/xfrm6_policy.c:149
CPU: 1 PID: 18994 Comm: syz-executor5 Not tainted 4.19.0-rc7+ #69
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+0x306/0x460 lib/dump_stack.c:113
 kmsan_report+0x1a2/0x2e0 mm/kmsan/kmsan.c:917
 __msan_warning+0x7c/0xe0 mm/kmsan/kmsan_instr.c:500
 _decode_session6+0x635/0x1630 net/ipv6/xfrm6_policy.c:149
 __xfrm_decode_session+0x156/0x200 net/xfrm/xfrm_policy.c:2299
 xfrm_decode_session_reverse include/net/xfrm.h:1239 [inline]
 icmpv6_route_lookup net/ipv6/icmp.c:372 [inline]
 icmp6_send+0x3037/0x3c50 net/ipv6/icmp.c:551
 icmpv6_send+0xe5/0x110 net/ipv6/ip6_icmp.c:43
 ip6_fragment+0xc95/0x50c0 net/ipv6/ip6_output.c:859
 ip6_finish_output+0xad0/0xc80 net/ipv6/ip6_output.c:152
 NF_HOOK_COND include/linux/netfilter.h:278 [inline]
 ip6_output+0x5a0/0x6e0 net/ipv6/ip6_output.c:171
 dst_output include/net/dst.h:444 [inline]
 ip6_local_out+0x164/0x1d0 net/ipv6/output_core.c:176
 ip6_send_skb net/ipv6/ip6_output.c:1695 [inline]
 ip6_push_pending_frames+0x218/0x4d0 net/ipv6/ip6_output.c:1715
 rawv6_push_pending_frames net/ipv6/raw.c:616 [inline]
 rawv6_sendmsg+0x4293/0x54d0 net/ipv6/raw.c:944
 inet_sendmsg+0x4d8/0x7f0 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 sock_write_iter+0x404/0x4d0 net/socket.c:900
 do_iter_readv_writev+0x822/0xab0 include/linux/fs.h:1802
 do_iter_write+0x302/0xd80 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+0x9b/0xb0 fs/read_write.c:1109
 __x64_sys_writev+0x4a/0x70 fs/read_write.c:1109
 do_syscall_64+0xbe/0x100 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x457569
Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f1ff46c1c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569
RDX: 0000000000000001 RSI: 0000000020000180 RDI: 0000000000000003
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1ff46c26d4
R13: 00000000004c30b5 R14: 00000000004d9078 R15: 00000000ffffffff

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:255 [inline]
 kmsan_internal_poison_shadow+0xc8/0x1d0 mm/kmsan/kmsan.c:180
 kmsan_kmalloc+0xa4/0x120 mm/kmsan/kmsan_hooks.c:104
 kmsan_slab_alloc+0x10/0x20 mm/kmsan/kmsan_hooks.c:113
 slab_post_alloc_hook mm/slab.h:446 [inline]
 slab_alloc_node mm/slub.c:2727 [inline]
 __kmalloc_node_track_caller+0xb43/0x1400 mm/slub.c:4360
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 pskb_expand_head+0x319/0x1d00 net/core/skbuff.c:1461
 __pskb_pull_tail+0x1db/0x21c0 net/core/skbuff.c:1895
 pskb_may_pull include/linux/skbuff.h:2127 [inline]
 nf_ct_frag6_gather+0x108f/0x5cc0 net/ipv6/netfilter/nf_conntrack_reasm.c:555
 ipv6_defrag+0x501/0x5c0 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:69
 nf_hook_entry_hookfn include/linux/netfilter.h:119 [inline]
 nf_hook_slow+0x15c/0x3d0 net/netfilter/core.c:511
 nf_hook include/linux/netfilter.h:244 [inline]
 __ip6_local_out+0x57e/0x770 net/ipv6/output_core.c:164
 ip6_local_out+0xa4/0x1d0 net/ipv6/output_core.c:174
 ip6_send_skb net/ipv6/ip6_output.c:1695 [inline]
 ip6_push_pending_frames+0x218/0x4d0 net/ipv6/ip6_output.c:1715
 rawv6_push_pending_frames net/ipv6/raw.c:616 [inline]
 rawv6_sendmsg+0x4293/0x54d0 net/ipv6/raw.c:944
 inet_sendmsg+0x4d8/0x7f0 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 sock_write_iter+0x404/0x4d0 net/socket.c:900
 do_iter_readv_writev+0x822/0xab0 include/linux/fs.h:1802
 do_iter_write+0x302/0xd80 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+0x9b/0xb0 fs/read_write.c:1109
 __x64_sys_writev+0x4a/0x70 fs/read_write.c:1109
 do_syscall_64+0xbe/0x100 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
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