syzbot

device ifb0 entered promiscuous mode
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BUG: KMSAN: uninit-value in tcp_ack_update_window net/ipv4/tcp_input.c:3325 [inline]
BUG: KMSAN: uninit-value in tcp_ack+0x1a4c/0x8770 net/ipv4/tcp_input.c:3576
CPU: 0 PID: 8 Comm: ksoftirqd/0 Not tainted 4.17.0+ #16
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+0x185/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x188/0x2a0 mm/kmsan/kmsan.c:1352
 __msan_warning_32+0x70/0xc0 mm/kmsan/kmsan_instr.c:634
 tcp_ack_update_window net/ipv4/tcp_input.c:3325 [inline]
 tcp_ack+0x1a4c/0x8770 net/ipv4/tcp_input.c:3576
 tcp_rcv_established+0xfca/0x2bb0 net/ipv4/tcp_input.c:5451
 tcp_v4_do_rcv+0x6d2/0xd90 net/ipv4/tcp_ipv4.c:1477
 tcp_v4_rcv+0x676e/0x6cd0 net/ipv4/tcp_ipv4.c:1765
 ip_local_deliver_finish+0x887/0xed0 net/ipv4/ip_input.c:215
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ip_local_deliver+0x43c/0x4e0 net/ipv4/ip_input.c:256
 dst_input include/net/dst.h:450 [inline]
 ip_rcv_finish+0xa1b/0x1d10 net/ipv4/ip_input.c:396
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ip_rcv+0x1168/0x16a0 net/ipv4/ip_input.c:492
 __netif_receive_skb_core+0x47f3/0x4aa0 net/core/dev.c:4592
 __netif_receive_skb net/core/dev.c:4657 [inline]
 process_backlog+0x62d/0xe20 net/core/dev.c:5337
 napi_poll net/core/dev.c:5735 [inline]
 net_rx_action+0x766/0x1a80 net/core/dev.c:5801
 __do_softirq+0x592/0x979 kernel/softirq.c:285
 run_ksoftirqd+0x24/0x40 kernel/softirq.c:649
 smpboot_thread_fn+0x4ac/0x9a0 kernel/smpboot.c:164
 kthread+0x4db/0x6c0 kernel/kthread.c:241
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:415

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:287 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:302 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:692
 kmsan_memcpy_origins+0x11d/0x170 mm/kmsan/kmsan.c:535
 __msan_memcpy+0xda/0x130 mm/kmsan/kmsan_instr.c:427
 pskb_expand_head+0x3a6/0x1a70 net/core/skbuff.c:1470
 ___pskb_trim+0x2e4/0x1ae0 net/core/skbuff.c:1772
 __pskb_trim include/linux/skbuff.h:2488 [inline]
 pskb_trim include/linux/skbuff.h:2495 [inline]
 sk_filter_trim_cap+0x523/0xa20 net/core/filter.c:106
 tcp_filter net/ipv4/tcp_ipv4.c:1594 [inline]
 tcp_v4_rcv+0x4f33/0x6cd0 net/ipv4/tcp_ipv4.c:1746
 ip_local_deliver_finish+0x887/0xed0 net/ipv4/ip_input.c:215
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ip_local_deliver+0x43c/0x4e0 net/ipv4/ip_input.c:256
 dst_input include/net/dst.h:450 [inline]
 ip_rcv_finish+0xa1b/0x1d10 net/ipv4/ip_input.c:396
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ip_rcv+0x1168/0x16a0 net/ipv4/ip_input.c:492
 __netif_receive_skb_core+0x47f3/0x4aa0 net/core/dev.c:4592
 __netif_receive_skb net/core/dev.c:4657 [inline]
 process_backlog+0x62d/0xe20 net/core/dev.c:5337
 napi_poll net/core/dev.c:5735 [inline]
 net_rx_action+0x766/0x1a80 net/core/dev.c:5801
 __do_softirq+0x592/0x979 kernel/softirq.c:285

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:287 [inline]
 kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:197
 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:323
 kmsan_slab_alloc+0x10/0x20 mm/kmsan/kmsan.c:330
 slab_post_alloc_hook mm/slab.h:446 [inline]
 slab_alloc_node mm/slub.c:2753 [inline]
 __kmalloc_node_track_caller+0xb35/0x11b0 mm/slub.c:4395
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x2cb/0x9e0 net/core/skbuff.c:206
 alloc_skb_fclone include/linux/skbuff.h:1030 [inline]
 sk_stream_alloc_skb+0x17c/0xcf0 net/ipv4/tcp.c:875
 tcp_sendmsg_locked+0x237e/0x6610 net/ipv4/tcp.c:1290
 tcp_sendmsg+0xb2/0x100 net/ipv4/tcp.c:1447
 inet_sendmsg+0x3fc/0x760 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg net/socket.c:639 [inline]
 __sys_sendto+0x6c4/0x7e0 net/socket.c:1789
 __do_sys_sendto net/socket.c:1801 [inline]
 __se_sys_sendto net/socket.c:1797 [inline]
 __x64_sys_sendto+0x1a1/0x210 net/socket.c:1797
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
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