=====================================================
BUG: KMSAN: uninit-value in ____bpf_skb_get_nlattr net/core/filter.c:144 [inline]
BUG: KMSAN: uninit-value in bpf_skb_get_nlattr+0x145/0x290 net/core/filter.c:134
CPU: 0 PID: 8462 Comm: syz-fuzzer Not tainted 5.8.0-rc5-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+0x1df/0x240 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215
 ____bpf_skb_get_nlattr net/core/filter.c:144 [inline]
 bpf_skb_get_nlattr+0x145/0x290 net/core/filter.c:134
 ___bpf_prog_run+0x214d/0x97a0 kernel/bpf/core.c:1516
 __bpf_prog_run32+0x101/0x170 kernel/bpf/core.c:1681
 bpf_dispatcher_nop_func include/linux/bpf.h:556 [inline]
 bpf_prog_run_pin_on_cpu include/linux/filter.h:597 [inline]
 bpf_prog_run_clear_cb include/linux/filter.h:719 [inline]
 run_filter net/packet/af_packet.c:2012 [inline]
 packet_rcv+0x70f/0x2150 net/packet/af_packet.c:2085
 dev_queue_xmit_nit+0x11a0/0x1280 net/core/dev.c:2355
 xmit_one net/core/dev.c:3552 [inline]
 dev_hard_start_xmit+0x20c/0xa70 net/core/dev.c:3572
 __dev_queue_xmit+0x2f8d/0x3b20 net/core/dev.c:4131
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:4164
 neigh_hh_output include/net/neighbour.h:498 [inline]
 neigh_output include/net/neighbour.h:507 [inline]
 ip6_finish_output2+0x2057/0x2620 net/ipv6/ip6_output.c:117
 __ip6_finish_output+0x824/0x8e0 net/ipv6/ip6_output.c:143
 ip6_finish_output+0x166/0x410 net/ipv6/ip6_output.c:153
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip6_output+0x60a/0x770 net/ipv6/ip6_output.c:176
 dst_output include/net/dst.h:443 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 ip6_xmit+0x1f67/0x2710 net/ipv6/ip6_output.c:280
 inet6_csk_xmit+0x42b/0x570 net/ipv6/inet6_connection_sock.c:135
 __tcp_transmit_skb+0x440e/0x6090 net/ipv4/tcp_output.c:1240
 __tcp_send_ack+0x701/0x840 net/ipv4/tcp_output.c:3787
 tcp_send_ack+0x68/0x90 net/ipv4/tcp_output.c:3793
 tcp_delack_timer_handler+0x4f3/0x9b0 net/ipv4/tcp_timer.c:305
 tcp_delack_timer+0x1a5/0x370 net/ipv4/tcp_timer.c:332
 call_timer_fn+0x218/0x510 kernel/time/timer.c:1404
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers+0xd20/0x11c0 kernel/time/timer.c:1773
 run_timer_softirq+0x2d/0x50 kernel/time/timer.c:1786
 __do_softirq+0x311/0x83d kernel/softirq.c:293
 asm_call_on_stack+0x12/0x20 arch/x86/entry/entry_64.S:711
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:23 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:50 [inline]
 do_softirq_own_stack+0x7c/0xa0 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:390 [inline]
 __irq_exit_rcu+0x226/0x270 kernel/softirq.c:420
 irq_exit_rcu+0xe/0x10 kernel/softirq.c:432
 sysvec_apic_timer_interrupt+0x107/0x130 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:593
RIP: 0010:kmsan_slab_alloc+0xb4/0xe0 mm/kmsan/kmsan_hooks.c:83
Code: eb 0a ba 01 00 00 00 e8 1a ed ff ff be ff ff ff ff 65 0f c1 35 cd e0 91 7c ff ce 75 1c e8 44 6c 2e ff 4c 89 65 d8 ff 75 d8 9d <48> 83 c4 10 5b 41 5c 41 5e 41 5f 5d c3 0f 0b 48 c7 c7 ea 03 ca 90
RSP: 0018:ffffa2fc80e7b598 EFLAGS: 00000246
RAX: a40a702d9e74e900 RBX: ffff9423d995bc00 RCX: 0000000000000101
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff9423d995bc00
RBP: ffffa2fc80e7b5c8 R08: fffff3b08000000f R09: ffff9424efffb000
R10: 000000000000000f R11: ffffffff9020083d R12: 0000000000000246
R13: ffff9424ef402c40 R14: 0000000000082cc0 R15: ffff9424ef402c40
 slab_alloc_node mm/slub.c:2839 [inline]
 __kmalloc_node_track_caller+0xb40/0x1200 mm/slub.c:4478
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0x2fd/0xac0 net/core/skbuff.c:210
 alloc_skb_fclone include/linux/skbuff.h:1133 [inline]
 sk_stream_alloc_skb+0x3ee/0x1180 net/ipv4/tcp.c:884
 tcp_sendmsg_locked+0x28b0/0x6d00 net/ipv4/tcp.c:1291
 tcp_sendmsg+0xb2/0x100 net/ipv4/tcp.c:1441
 inet_sendmsg+0x178/0x2e0 net/ipv4/af_inet.c:814
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 sock_write_iter+0x651/0x720 net/socket.c:999
 call_write_iter include/linux/fs.h:1908 [inline]
 new_sync_write fs/read_write.c:503 [inline]
 vfs_write+0xd98/0x1480 fs/read_write.c:578
 ksys_write+0x267/0x450 fs/read_write.c:631
 __do_sys_write fs/read_write.c:643 [inline]
 __se_sys_write+0x92/0xb0 fs/read_write.c:640
 __x64_sys_write+0x4a/0x70 fs/read_write.c:640
 do_syscall_64+0xb0/0x150 arch/x86/entry/common.c:386
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4b3d8b
Code: Bad RIP value.
RSP: 002b:000000c00b0214e0 EFLAGS: 00000206 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000c00002c000 RCX: 00000000004b3d8b
RDX: 00000000000000f0 RSI: 000000c00000a200 RDI: 0000000000000006
RBP: 000000c00b021530 R08: 000000c00000a201 R09: 00000000000000f0
R10: 0000000000000003 R11: 0000000000000206 R12: 0000000000000003
R13: 0000000000000410 R14: 000000000000007f R15: 00000000000009a1

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
 __msan_chain_origin+0x50/0x90 mm/kmsan/kmsan_instr.c:165
 ___bpf_prog_run+0x6cbe/0x97a0 kernel/bpf/core.c:1391
 __bpf_prog_run32+0x101/0x170 kernel/bpf/core.c:1681
 bpf_dispatcher_nop_func include/linux/bpf.h:556 [inline]
 bpf_prog_run_pin_on_cpu include/linux/filter.h:597 [inline]
 bpf_prog_run_clear_cb include/linux/filter.h:719 [inline]
 run_filter net/packet/af_packet.c:2012 [inline]
 packet_rcv+0x70f/0x2150 net/packet/af_packet.c:2085
 dev_queue_xmit_nit+0x11a0/0x1280 net/core/dev.c:2355
 xmit_one net/core/dev.c:3552 [inline]
 dev_hard_start_xmit+0x20c/0xa70 net/core/dev.c:3572
 __dev_queue_xmit+0x2f8d/0x3b20 net/core/dev.c:4131
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:4164
 neigh_hh_output include/net/neighbour.h:498 [inline]
 neigh_output include/net/neighbour.h:507 [inline]
 ip6_finish_output2+0x2057/0x2620 net/ipv6/ip6_output.c:117
 __ip6_finish_output+0x824/0x8e0 net/ipv6/ip6_output.c:143
 ip6_finish_output+0x166/0x410 net/ipv6/ip6_output.c:153
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip6_output+0x60a/0x770 net/ipv6/ip6_output.c:176
 dst_output include/net/dst.h:443 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 ip6_xmit+0x1f67/0x2710 net/ipv6/ip6_output.c:280
 inet6_csk_xmit+0x42b/0x570 net/ipv6/inet6_connection_sock.c:135
 __tcp_transmit_skb+0x440e/0x6090 net/ipv4/tcp_output.c:1240
 __tcp_send_ack+0x701/0x840 net/ipv4/tcp_output.c:3787
 tcp_send_ack+0x68/0x90 net/ipv4/tcp_output.c:3793
 tcp_delack_timer_handler+0x4f3/0x9b0 net/ipv4/tcp_timer.c:305
 tcp_delack_timer+0x1a5/0x370 net/ipv4/tcp_timer.c:332
 call_timer_fn+0x218/0x510 kernel/time/timer.c:1404
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers+0xd20/0x11c0 kernel/time/timer.c:1773
 run_timer_softirq+0x2d/0x50 kernel/time/timer.c:1786
 __do_softirq+0x311/0x83d kernel/softirq.c:293

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
 __msan_chain_origin+0x50/0x90 mm/kmsan/kmsan_instr.c:165
 ___bpf_prog_run+0x6c64/0x97a0 kernel/bpf/core.c:1391
 __bpf_prog_run32+0x101/0x170 kernel/bpf/core.c:1681
 bpf_dispatcher_nop_func include/linux/bpf.h:556 [inline]
 bpf_prog_run_pin_on_cpu include/linux/filter.h:597 [inline]
 bpf_prog_run_clear_cb include/linux/filter.h:719 [inline]
 run_filter net/packet/af_packet.c:2012 [inline]
 packet_rcv+0x70f/0x2150 net/packet/af_packet.c:2085
 dev_queue_xmit_nit+0x11a0/0x1280 net/core/dev.c:2355
 xmit_one net/core/dev.c:3552 [inline]
 dev_hard_start_xmit+0x20c/0xa70 net/core/dev.c:3572
 __dev_queue_xmit+0x2f8d/0x3b20 net/core/dev.c:4131
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:4164
 neigh_hh_output include/net/neighbour.h:498 [inline]
 neigh_output include/net/neighbour.h:507 [inline]
 ip6_finish_output2+0x2057/0x2620 net/ipv6/ip6_output.c:117
 __ip6_finish_output+0x824/0x8e0 net/ipv6/ip6_output.c:143
 ip6_finish_output+0x166/0x410 net/ipv6/ip6_output.c:153
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip6_output+0x60a/0x770 net/ipv6/ip6_output.c:176
 dst_output include/net/dst.h:443 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 ip6_xmit+0x1f67/0x2710 net/ipv6/ip6_output.c:280
 inet6_csk_xmit+0x42b/0x570 net/ipv6/inet6_connection_sock.c:135
 __tcp_transmit_skb+0x440e/0x6090 net/ipv4/tcp_output.c:1240
 __tcp_send_ack+0x701/0x840 net/ipv4/tcp_output.c:3787
 tcp_send_ack+0x68/0x90 net/ipv4/tcp_output.c:3793
 tcp_delack_timer_handler+0x4f3/0x9b0 net/ipv4/tcp_timer.c:305
 tcp_delack_timer+0x1a5/0x370 net/ipv4/tcp_timer.c:332
 call_timer_fn+0x218/0x510 kernel/time/timer.c:1404
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers+0xd20/0x11c0 kernel/time/timer.c:1773
 run_timer_softirq+0x2d/0x50 kernel/time/timer.c:1786
 __do_softirq+0x311/0x83d kernel/softirq.c:293

Local variable ----regs@__bpf_prog_run32 created at:
 __bpf_prog_run32+0x87/0x170 kernel/bpf/core.c:1681
 __bpf_prog_run32+0x87/0x170 kernel/bpf/core.c:1681
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