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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: 8576 Comm: syz-executor.0 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_pending_frames+0x150/0x5b0 net/ipv4/tcp_output.c:2862
 tcp_send_fin+0x1678/0x1b40 net/ipv4/tcp_output.c:3419
 tcp_close+0x19b4/0x1b50 net/ipv4/tcp.c:2493
 inet_release+0x30c/0x390 net/ipv4/af_inet.c:431
 __sock_release net/socket.c:596 [inline]
 sock_close+0x150/0x450 net/socket.c:1277
 __fput+0x6c3/0xf10 fs/file_table.c:281
 ____fput+0x37/0x40 fs/file_table.c:314
 task_work_run+0x140/0x280 kernel/task_work.c:151
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:164 [inline]
 exit_to_user_mode_prepare+0x3c9/0x490 kernel/entry/common.c:191
 syscall_exit_to_user_mode+0x35/0x50 kernel/entry/common.c:266
 do_syscall_64+0xc5/0x140 arch/x86/entry/common.c:58
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x417b71
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 a4 1a 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00000000016afbd0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000007 RCX: 0000000000417b71
RDX: 0000000000000000 RSI: 00007fcce0d5e004 RDI: 0000000000000006
RBP: 0000000000000001 R08: 0000000000001ad9 R09: 00000000f5921add
R10: 00000000016afcb0 R11: 0000000000000293 R12: ffffffffffffffff
R13: 0000000000068507 R14: 00000000000003e8 R15: 000000000119bf8c

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
 alloc_skb_fclone include/linux/skbuff.h:1144 [inline]
 tcp_send_fin+0x4f5/0x1b40 net/ipv4/tcp_output.c:3407
 tcp_close+0x19b4/0x1b50 net/ipv4/tcp.c:2493
 inet_release+0x30c/0x390 net/ipv4/af_inet.c:431
 __sock_release net/socket.c:596 [inline]
 sock_close+0x150/0x450 net/socket.c:1277
 __fput+0x6c3/0xf10 fs/file_table.c:281
 ____fput+0x37/0x40 fs/file_table.c:314
 task_work_run+0x140/0x280 kernel/task_work.c:151
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:164 [inline]
 exit_to_user_mode_prepare+0x3c9/0x490 kernel/entry/common.c:191
 syscall_exit_to_user_mode+0x35/0x50 kernel/entry/common.c:266
 do_syscall_64+0xc5/0x140 arch/x86/entry/common.c:58
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
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