syzbot

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BUG: KMSAN: uninit-value in kmsan_check_memory+0xd/0x10 mm/kmsan/kmsan_hooks.c:428
CPU: 1 PID: 8727 Comm: syz-executor164 Not tainted 5.8.0-rc5-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+0x1df/0x240 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
 kmsan_internal_check_memory+0x238/0x3d0 mm/kmsan/kmsan.c:423
 kmsan_check_memory+0xd/0x10 mm/kmsan/kmsan_hooks.c:428
 instrument_copy_to_user include/linux/instrumented.h:91 [inline]
 copyout lib/iov_iter.c:142 [inline]
 _copy_to_iter+0x3d4/0x26e0 lib/iov_iter.c:631
 copy_to_iter include/linux/uio.h:138 [inline]
 simple_copy_to_iter net/core/datagram.c:519 [inline]
 __skb_datagram_iter+0x2bb/0x1220 net/core/datagram.c:425
 skb_copy_datagram_iter+0x292/0x2b0 net/core/datagram.c:533
 skb_copy_datagram_msg include/linux/skbuff.h:3511 [inline]
 packet_recvmsg+0x630/0x1c40 net/packet/af_packet.c:3378
 sock_recvmsg_nosec net/socket.c:886 [inline]
 sock_recvmsg net/socket.c:904 [inline]
 sock_read_iter+0x750/0x760 net/socket.c:977
 call_read_iter include/linux/fs.h:1902 [inline]
 new_sync_read fs/read_write.c:415 [inline]
 vfs_read+0xc67/0x1230 fs/read_write.c:481
 ksys_read+0x267/0x450 fs/read_write.c:607
 __do_sys_read fs/read_write.c:617 [inline]
 __se_sys_read+0x92/0xb0 fs/read_write.c:615
 __ia32_sys_read+0x4a/0x70 fs/read_write.c:615
 do_syscall_32_irqs_on arch/x86/entry/common.c:430 [inline]
 __do_fast_syscall_32+0x2aa/0x400 arch/x86/entry/common.c:477
 do_fast_syscall_32+0x6b/0xd0 arch/x86/entry/common.c:505
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:554
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7ffa549
Code: Bad RIP value.
RSP: 002b:00000000ffae3cec EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000020000000
RDX: 000000000000003c RSI: 00000000f7ffa28c RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

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:3145 [inline]
 skb_cow_head include/linux/skbuff.h:3179 [inline]
 batadv_skb_head_push+0x234/0x350 net/batman-adv/soft-interface.c:75
 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+0x1540/0x1f30 kernel/workqueue.c:2269
 worker_thread+0xed2/0x23f0 kernel/workqueue.c:2415
 kthread+0x515/0x550 kernel/kthread.c:292
 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:293

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:269 [inline]
 kmsan_alloc_page+0xb9/0x180 mm/kmsan/kmsan_shadow.c:293
 __alloc_pages_nodemask+0x56a2/0x5dc0 mm/page_alloc.c:4889
 __alloc_pages include/linux/gfp.h:509 [inline]
 __alloc_pages_node include/linux/gfp.h:522 [inline]
 alloc_pages_node include/linux/gfp.h:536 [inline]
 __page_frag_cache_refill mm/page_alloc.c:4964 [inline]
 page_frag_alloc+0x3ae/0x910 mm/page_alloc.c:4994
 __napi_alloc_skb+0x193/0xa60 net/core/skbuff.c:519
 napi_alloc_skb include/linux/skbuff.h:2850 [inline]
 page_to_skb+0x1a2/0x1390 drivers/net/virtio_net.c:384
 receive_mergeable drivers/net/virtio_net.c:944 [inline]
 receive_buf+0xf9e/0x9760 drivers/net/virtio_net.c:1054
 virtnet_receive drivers/net/virtio_net.c:1346 [inline]
 virtnet_poll+0x64b/0x19f0 drivers/net/virtio_net.c:1451
 napi_poll net/core/dev.c:6684 [inline]
 net_rx_action+0x746/0x1aa0 net/core/dev.c:6752
 __do_softirq+0x311/0x83d kernel/softirq.c:293

Bytes 52-53 of 60 are uninitialized
Memory access of size 60 starts at ffff9f09f4c35c40
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