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BUG: KMSAN: uninit-value in __arch_swab32 arch/x86/include/uapi/asm/swab.h:10 [inline]
BUG: KMSAN: uninit-value in __fswab32 include/uapi/linux/swab.h:60 [inline]
BUG: KMSAN: uninit-value in gre_parse_header+0x1b2d/0x1e70 net/ipv4/gre_demux.c:139
CPU: 1 PID: 24265 Comm: syz-executor.4 Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:118
 __msan_warning+0x5f/0xa0 mm/kmsan/kmsan_instr.c:197
 __arch_swab32 arch/x86/include/uapi/asm/swab.h:10 [inline]
 __fswab32 include/uapi/linux/swab.h:60 [inline]
 gre_parse_header+0x1b2d/0x1e70 net/ipv4/gre_demux.c:139
 gre_rcv+0x203/0x1e90 net/ipv4/ip_gre.c:431
 gre_rcv+0x321/0x410 net/ipv4/gre_demux.c:163
 ip_protocol_deliver_rcu+0x572/0xc50 net/ipv4/ip_input.c:204
 ip_local_deliver_finish net/ipv4/ip_input.c:231 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ip_local_deliver+0x585/0x8d0 net/ipv4/ip_input.c:252
 dst_input include/net/dst.h:449 [inline]
 ip_rcv_finish net/ipv4/ip_input.c:428 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ip_rcv+0x599/0x820 net/ipv4/ip_input.c:539
 __netif_receive_skb_one_core net/core/dev.c:5315 [inline]
 __netif_receive_skb+0x1ec/0x640 net/core/dev.c:5429
 process_backlog+0x517/0xbd0 net/core/dev.c:6319
 napi_poll+0x40a/0x1020 net/core/dev.c:6763
 net_rx_action+0x34c/0xd30 net/core/dev.c:6833
 __do_softirq+0x1a9/0x6fa kernel/softirq.c:298
 asm_call_irq_on_stack+0xf/0x20
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline]
 do_softirq_own_stack+0x6e/0x90 arch/x86/kernel/irq_64.c:77
 do_softirq kernel/softirq.c:343 [inline]
 __local_bh_enable_ip+0x184/0x1d0 kernel/softirq.c:195
 local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32
 rcu_read_unlock_bh include/linux/rcupdate.h:730 [inline]
 ip_finish_output2+0x2454/0x2940 net/ipv4/ip_output.c:231
 __ip_finish_output+0xd08/0x1090 net/ipv4/ip_output.c:308
 ip_finish_output+0x329/0x480 net/ipv4/ip_output.c:318
 NF_HOOK_COND include/linux/netfilter.h:290 [inline]
 ip_output+0x32e/0x6d0 net/ipv4/ip_output.c:432
 dst_output include/net/dst.h:443 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 __ip_queue_xmit+0x1e3d/0x23b0 net/ipv4/ip_output.c:532
 ip_queue_xmit+0xcc/0xf0 net/ipv4/ip_output.c:546
 __tcp_transmit_skb+0x4cb8/0x5e20 net/ipv4/tcp_output.c:1404
 tcp_transmit_skb net/ipv4/tcp_output.c:1422 [inline]
 tcp_write_xmit+0x462b/0xe770 net/ipv4/tcp_output.c:2684
 tcp_push_one+0x1b6/0x240 net/ipv4/tcp_output.c:2876
 tcp_sendmsg_locked+0x5543/0x7ec0 net/ipv4/tcp.c:1395
 tcp_sendmsg+0xb2/0x100 net/ipv4/tcp.c:1444
 inet_sendmsg+0x15b/0x1d0 net/ipv4/af_inet.c:817
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:671 [inline]
 ____sys_sendmsg+0xcfc/0x12f0 net/socket.c:2353
 ___sys_sendmsg net/socket.c:2407 [inline]
 __sys_sendmsg+0x6f1/0x840 net/socket.c:2440
 __do_sys_sendmsg net/socket.c:2449 [inline]
 __se_sys_sendmsg+0x97/0xb0 net/socket.c:2447
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2447
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e219
Code: 0d b4 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 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fa440842c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045e219
RDX: 0000000000006d70 RSI: 0000000020001400 RDI: 0000000000000006
RBP: 000000000119c068 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119c034
R13: 00000000016afb5f R14: 00007fa4408439c0 R15: 000000000119c034

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+0x8d/0xe0 mm/kmsan/kmsan_hooks.c:76
 slab_alloc_node mm/slub.c:2906 [inline]
 __kmalloc_node_track_caller+0xa48/0x1610 mm/slub.c:4512
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0x318/0xb00 net/core/skbuff.c:210
 skb_segment+0x22df/0x77b0 net/core/skbuff.c:3894
 tcp_gso_segment+0x9b9/0x2b40 net/ipv4/tcp_offload.c:98
 tcp4_gso_segment+0x28e/0x660 net/ipv4/tcp_offload.c:51
 inet_gso_segment+0xac5/0x1d90 net/ipv4/af_inet.c:1378
 skb_mac_gso_segment+0x495/0x7d0 net/core/dev.c:3321
 __skb_gso_segment+0x791/0xc30 net/core/dev.c:3394
 skb_gso_segment include/linux/netdevice.h:4668 [inline]
 validate_xmit_skb+0xc5a/0x1ae0 net/core/dev.c:3634
 validate_xmit_skb_list+0x165/0x370 net/core/dev.c:3684
 sch_direct_xmit+0x1c9/0x1a60 net/sched/sch_generic.c:299
 qdisc_restart net/sched/sch_generic.c:377 [inline]
 __qdisc_run+0x35b/0x490 net/sched/sch_generic.c:385
 qdisc_run include/net/pkt_sched.h:131 [inline]
 __dev_xmit_skb net/core/dev.c:3755 [inline]
 __dev_queue_xmit+0x26a1/0x4590 net/core/dev.c:4108
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:4173
 neigh_resolve_output+0xc65/0xcf0 net/core/neighbour.c:1489
 neigh_output include/net/neighbour.h:509 [inline]
 ip_finish_output2+0x1d18/0x2940 net/ipv4/ip_output.c:230
 __ip_finish_output+0xd08/0x1090 net/ipv4/ip_output.c:308
 ip_finish_output+0x329/0x480 net/ipv4/ip_output.c:318
 NF_HOOK_COND include/linux/netfilter.h:290 [inline]
 ip_output+0x32e/0x6d0 net/ipv4/ip_output.c:432
 dst_output include/net/dst.h:443 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 __ip_queue_xmit+0x1e3d/0x23b0 net/ipv4/ip_output.c:532
 ip_queue_xmit+0xcc/0xf0 net/ipv4/ip_output.c:546
 __tcp_transmit_skb+0x4cb8/0x5e20 net/ipv4/tcp_output.c:1404
 tcp_transmit_skb net/ipv4/tcp_output.c:1422 [inline]
 tcp_write_xmit+0x462b/0xe770 net/ipv4/tcp_output.c:2684
 tcp_push_one+0x1b6/0x240 net/ipv4/tcp_output.c:2876
 tcp_sendmsg_locked+0x5543/0x7ec0 net/ipv4/tcp.c:1395
 tcp_sendmsg+0xb2/0x100 net/ipv4/tcp.c:1444
 inet_sendmsg+0x15b/0x1d0 net/ipv4/af_inet.c:817
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:671 [inline]
 ____sys_sendmsg+0xcfc/0x12f0 net/socket.c:2353
 ___sys_sendmsg net/socket.c:2407 [inline]
 __sys_sendmsg+0x6f1/0x840 net/socket.c:2440
 __do_sys_sendmsg net/socket.c:2449 [inline]
 __se_sys_sendmsg+0x97/0xb0 net/socket.c:2447
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2447
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
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