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BUG: KMSAN: uninit-value in ipv6_find_tlv+0x4a8/0x500 net/ipv6/exthdrs_core.c:147
CPU: 0 PID: 6471 Comm: syz-executor.4 Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x24c/0x2e0 lib/dump_stack.c:120
 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:121
 __msan_warning+0x5c/0xa0 mm/kmsan/kmsan_instr.c:197
 ipv6_find_tlv+0x4a8/0x500 net/ipv6/exthdrs_core.c:147
 ip6_find_1stfragopt+0x2a5/0x5e0 net/ipv6/output_core.c:102
 ip6_fragment+0x318/0x3eb0 net/ipv6/ip6_output.c:815
 __ip6_finish_output+0xb3a/0xee0 net/ipv6/ip6_output.c:180
 ip6_finish_output+0x329/0x480 net/ipv6/ip6_output.c:192
 NF_HOOK_COND include/linux/netfilter.h:290 [inline]
 ip6_output+0x4a4/0x7f0 net/ipv6/ip6_output.c:215
 dst_output include/net/dst.h:448 [inline]
 ip6_local_out+0x17b/0x1e0 net/ipv6/output_core.c:179
 ip6_send_skb net/ipv6/ip6_output.c:1904 [inline]
 ip6_push_pending_frames+0x243/0x570 net/ipv6/ip6_output.c:1924
 rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
 rawv6_sendmsg+0x40f4/0x46b0 net/ipv6/raw.c:956
 inet_sendmsg+0x15b/0x1d0 net/ipv4/af_inet.c:821
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg net/socket.c:674 [inline]
 sock_write_iter+0x585/0x680 net/socket.c:1001
 call_write_iter include/linux/fs.h:1977 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x1083/0x1b00 fs/read_write.c:605
 ksys_write+0x275/0x500 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write+0x92/0xb0 fs/read_write.c:667
 __x64_sys_write+0x4a/0x70 fs/read_write.c:667
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665d9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8159b66188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665d9
RDX: 000000000000000b RSI: 0000000020000000 RDI: 0000000000000003
RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038
R13: 0000000000a9fb1f R14: 00007f8159b66300 R15: 0000000000022000

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline]
 kmsan_internal_poison_shadow+0x5c/0xf0 mm/kmsan/kmsan.c:104
 kmsan_slab_alloc+0x8e/0xe0 mm/kmsan/kmsan_hooks.c:76
 slab_alloc_node mm/slub.c:2922 [inline]
 __kmalloc_node_track_caller+0xa4f/0x1470 mm/slub.c:4609
 kmalloc_reserve net/core/skbuff.c:353 [inline]
 __alloc_skb+0x4dd/0xe90 net/core/skbuff.c:424
 alloc_skb include/linux/skbuff.h:1103 [inline]
 alloc_skb_with_frags+0x1f3/0xc10 net/core/skbuff.c:5948
 sock_alloc_send_pskb+0xdc1/0xf90 net/core/sock.c:2362
 sock_alloc_send_skb+0xca/0xe0 net/core/sock.c:2379
 __ip6_append_data+0x5336/0x74d0 net/ipv6/ip6_output.c:1621
 ip6_append_data+0x44b/0x6e0 net/ipv6/ip6_output.c:1796
 rawv6_sendmsg+0x2af4/0x46b0 net/ipv6/raw.c:949
 inet_sendmsg+0x15b/0x1d0 net/ipv4/af_inet.c:821
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg net/socket.c:674 [inline]
 sock_write_iter+0x585/0x680 net/socket.c:1001
 call_write_iter include/linux/fs.h:1977 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x1083/0x1b00 fs/read_write.c:605
 ksys_write+0x275/0x500 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write+0x92/0xb0 fs/read_write.c:667
 __x64_sys_write+0x4a/0x70 fs/read_write.c:667
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xae
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