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BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:251
CPU: 0 PID: 2914 Comm: syz-executor.5 Not tainted 5.6.0-rc7-syzkaller #0
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+0x1c9/0x220 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118
 kmsan_internal_check_memory+0x238/0x3d0 mm/kmsan/kmsan.c:423
 kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:251
 copyout+0x15a/0x1e0 lib/iov_iter.c:145
 _copy_to_iter+0x34e/0x2420 lib/iov_iter.c:633
 copy_to_iter include/linux/uio.h:138 [inline]
 simple_copy_to_iter+0xd7/0x130 net/core/datagram.c:522
 __skb_datagram_iter+0x25f/0xfc0 net/core/datagram.c:430
 skb_copy_datagram_iter+0x292/0x2b0 net/core/datagram.c:536
 skb_copy_datagram_msg include/linux/skbuff.h:3543 [inline]
 packet_recvmsg+0x630/0x1c40 net/packet/af_packet.c:3367
 ____sys_recvmsg+0x1173/0x1240 net/socket.c:886
 ___sys_recvmsg net/socket.c:2610 [inline]
 do_recvmmsg+0x6f3/0x1eb0 net/socket.c:2708
 __sys_recvmmsg net/socket.c:2787 [inline]
 __do_sys_recvmmsg net/socket.c:2810 [inline]
 __se_sys_recvmmsg+0x1d1/0x350 net/socket.c:2803
 __x64_sys_recvmmsg+0x62/0x80 net/socket.c:2803
 do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c829
Code: 0d b7 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 b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffad2700c78 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00000000004fb460 RCX: 000000000045c829
RDX: 0000000020004582 RSI: 0000000020004b40 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000008a2 R14: 00000000004cb548 R15: 00007ffad27016d4

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline]
 kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:310
 kmsan_memcpy_memmove_metadata+0x272/0x2e0 mm/kmsan/kmsan.c:247
 kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:267
 __msan_memcpy+0x43/0x50 mm/kmsan/kmsan_instr.c:116
 pskb_expand_head+0x38b/0x1b00 net/core/skbuff.c:1636
 __skb_cow include/linux/skbuff.h:3169 [inline]
 skb_cow_head include/linux/skbuff.h:3203 [inline]
 batadv_skb_head_push+0x234/0x350 net/batman-adv/soft-interface.c:74
 batadv_send_skb_packet+0x1a7/0x8c0 net/batman-adv/send.c:86
 batadv_send_broadcast_skb+0x76/0x90 net/batman-adv/send.c:127
 batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:393 [inline]
 batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:419 [inline]
 batadv_iv_send_outstanding_bat_ogm_packet+0x97e/0xd50 net/batman-adv/bat_iv_ogm.c:1710
 process_one_work+0x1555/0x1f40 kernel/workqueue.c:2266
 worker_thread+0xef6/0x2450 kernel/workqueue.c:2412
 kthread+0x4b5/0x4f0 kernel/kthread.c:256
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:353

Uninit was created at:
 kmsan_save_stack_with_flags+0x3c/0x90 mm/kmsan/kmsan.c:144
 kmsan_internal_alloc_meta_for_pages mm/kmsan/kmsan_shadow.c:280 [inline]
 kmsan_alloc_page+0xb9/0x180 mm/kmsan/kmsan_shadow.c:304
 __alloc_pages_nodemask+0x5712/0x5e80 mm/page_alloc.c:4777
 __alloc_pages include/linux/gfp.h:496 [inline]
 __alloc_pages_node include/linux/gfp.h:509 [inline]
 alloc_pages_node include/linux/gfp.h:523 [inline]
 __page_frag_cache_refill mm/page_alloc.c:4852 [inline]
 page_frag_alloc+0x3ae/0x910 mm/page_alloc.c:4882
 __napi_alloc_skb+0x193/0xa60 net/core/skbuff.c:519
 napi_alloc_skb include/linux/skbuff.h:2874 [inline]
 page_to_skb+0x19f/0x1100 drivers/net/virtio_net.c:384
 receive_mergeable drivers/net/virtio_net.c:924 [inline]
 receive_buf+0xe79/0x8b30 drivers/net/virtio_net.c:1033
 virtnet_receive drivers/net/virtio_net.c:1323 [inline]
 virtnet_poll+0x64b/0x19f0 drivers/net/virtio_net.c:1428
 napi_poll net/core/dev.c:6571 [inline]
 net_rx_action+0x786/0x1aa0 net/core/dev.c:6639
 __do_softirq+0x311/0x83d kernel/softirq.c:293

Bytes 52-53 of 74 are uninitialized
Memory access of size 74 starts at ffff9d08772ff840
Data copied to user address 0000000020003380
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