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BUG: KMSAN: uninit-value in virtio_net_hdr_to_skb+0x1414/0x14f0 include/linux/virtio_net.h:86
CPU: 0 PID: 8930 Comm: syz-executor.1 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
 virtio_net_hdr_to_skb+0x1414/0x14f0 include/linux/virtio_net.h:86
 packet_snd net/packet/af_packet.c:2994 [inline]
 packet_sendmsg+0x85b8/0x99d0 net/packet/af_packet.c:3031
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg net/socket.c:674 [inline]
 kernel_sendmsg+0x22c/0x2f0 net/socket.c:694
 sock_no_sendpage+0x205/0x2b0 net/core/sock.c:2860
 kernel_sendpage+0x47a/0x590 net/socket.c:3631
 sock_sendpage+0x161/0x1a0 net/socket.c:947
 pipe_to_sendpage+0x3e4/0x520 fs/splice.c:364
 splice_from_pipe_feed fs/splice.c:418 [inline]
 __splice_from_pipe+0x5e3/0xff0 fs/splice.c:562
 splice_from_pipe fs/splice.c:597 [inline]
 generic_splice_sendpage+0x1d5/0x2c0 fs/splice.c:746
 do_splice_from fs/splice.c:767 [inline]
 do_splice+0x23c3/0x2c10 fs/splice.c:1079
 __do_splice fs/splice.c:1144 [inline]
 __do_sys_splice fs/splice.c:1350 [inline]
 __se_sys_splice+0x8fa/0xb50 fs/splice.c:1332
 __x64_sys_splice+0x6e/0x90 fs/splice.c:1332
 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:00007f502c30b188 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 000000000056c0f0 RCX: 00000000004665d9
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00000000004bfcb9 R08: 000000000004ffe0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c0f0
R13: 0000000000a9fb1f R14: 00007f502c30b300 R15: 0000000000022000

Uninit was created at:
 kmsan_save_stack_with_flags+0x3c/0x90 mm/kmsan/kmsan.c:121
 kmsan_alloc_page+0xd0/0x1e0 mm/kmsan/kmsan_shadow.c:274
 __alloc_pages_nodemask+0x827/0xf90 mm/page_alloc.c:5044
 alloc_pages_current+0x7b6/0xb60 mm/mempolicy.c:2277
 alloc_pages include/linux/gfp.h:561 [inline]
 alloc_slab_page mm/slub.c:1653 [inline]
 allocate_slab+0x364/0x1260 mm/slub.c:1793
 new_slab mm/slub.c:1856 [inline]
 new_slab_objects mm/slub.c:2602 [inline]
 ___slab_alloc+0xd42/0x1930 mm/slub.c:2765
 __slab_alloc mm/slub.c:2805 [inline]
 slab_alloc_node mm/slub.c:2886 [inline]
 slab_alloc mm/slub.c:2931 [inline]
 __kmalloc+0x47f/0x550 mm/slub.c:4068
 kmalloc_array include/linux/slab.h:594 [inline]
 kcalloc include/linux/slab.h:623 [inline]
 cache_create_net+0x116/0x4a0 net/sunrpc/cache.c:1733
 rsc_cache_create_net net/sunrpc/auth_gss/svcauth_gss.c:1944 [inline]
 gss_svc_init_net+0xca/0xa30 net/sunrpc/auth_gss/svcauth_gss.c:1972
 rpcsec_gss_init_net+0x41/0x50 net/sunrpc/auth_gss/auth_gss.c:2200
 ops_init+0x595/0x7e0 net/core/net_namespace.c:140
 setup_net+0x3ea/0x1560 net/core/net_namespace.c:333
 copy_net_ns+0x84c/0xc80 net/core/net_namespace.c:474
 create_new_namespaces+0x8c0/0x1270 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x268/0x340 kernel/nsproxy.c:226
 ksys_unshare+0xa98/0x1490 kernel/fork.c:2995
 __do_sys_unshare kernel/fork.c:3063 [inline]
 __se_sys_unshare+0x41/0x60 kernel/fork.c:3061
 __x64_sys_unshare+0x32/0x50 kernel/fork.c:3061
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xae
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