===================================================== BUG: KMSAN: uninit-value in kmsan_check_memory+0xd/0x10 mm/kmsan/kmsan_hooks.c:428 CPU: 1 PID: 31865 Comm: syz-executor.4 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 ____sys_recvmsg+0xf58/0x1020 net/socket.c:886 ___sys_recvmsg net/socket.c:2617 [inline] do_recvmmsg+0x99c/0x1ee0 net/socket.c:2715 __sys_recvmmsg net/socket.c:2794 [inline] __do_sys_recvmmsg net/socket.c:2817 [inline] __se_sys_recvmmsg+0x1d1/0x350 net/socket.c:2810 __x64_sys_recvmmsg+0x62/0x80 net/socket.c:2810 do_syscall_64+0xb0/0x150 arch/x86/entry/common.c:386 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45c1f9 Code: Bad RIP value. RSP: 002b:00007fb1b0643c78 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 0000000000025200 RCX: 000000000045c1f9 RDX: 0000000020004582 RSI: 0000000020004b40 RDI: 0000000000000003 RBP: 000000000078bf50 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 000000000078bf0c R13: 0000000000c9fb6f R14: 00007fb1b06449c0 R15: 000000000078bf0c 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 74 are uninitialized Memory access of size 74 starts at ffff9ea53e511440 =====================================================