syzbot

IPv4: Oversized IP packet from 172.20.20.10
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BUG: KCSAN: data-race in virtqueue_disable_cb / virtqueue_disable_cb

read to 0xffff8881020ef478 of 2 bytes by interrupt on cpu 1:
 virtqueue_disable_cb_split drivers/virtio/virtio_ring.c:873 [inline]
 virtqueue_disable_cb+0x58/0x150 drivers/virtio/virtio_ring.c:2570
 skb_xmit_done+0x65/0x140 drivers/net/virtio_net.c:784
 vring_interrupt+0x152/0x180 drivers/virtio/virtio_ring.c:2719
 __handle_irq_event_percpu+0x90/0x440 kernel/irq/handle.c:158
 handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
 handle_irq_event+0x64/0xf0 kernel/irq/handle.c:210
 handle_edge_irq+0x154/0x470 kernel/irq/chip.c:855
 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
 handle_irq arch/x86/kernel/irq.c:254 [inline]
 call_irq_handler arch/x86/kernel/irq.c:266 [inline]
 __common_interrupt+0x63/0x100 arch/x86/kernel/irq.c:292
 common_interrupt+0x7e/0x90 arch/x86/kernel/irq.c:285
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
 vm_normal_page mm/memory.c:604 [inline]
 copy_present_ptes mm/memory.c:992 [inline]
 copy_pte_range mm/memory.c:1174 [inline]
 copy_pmd_range mm/memory.c:1261 [inline]
 copy_pud_range mm/memory.c:1298 [inline]
 copy_p4d_range mm/memory.c:1322 [inline]
 copy_page_range+0xc0e/0x3c20 mm/memory.c:1410
 dup_mmap+0x885/0xf20 mm/mmap.c:1834
 dup_mm kernel/fork.c:1485 [inline]
 copy_mm+0x11a/0x370 kernel/fork.c:1537
 copy_process+0xd08/0x2000 kernel/fork.c:2175
 kernel_clone+0x16c/0x5c0 kernel/fork.c:2605
 __do_sys_clone kernel/fork.c:2748 [inline]
 __se_sys_clone kernel/fork.c:2732 [inline]
 __x64_sys_clone+0xe6/0x120 kernel/fork.c:2732
 x64_sys_call+0x119c/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:57
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff8881020ef478 of 2 bytes by interrupt on cpu 0:
 virtqueue_disable_cb_split drivers/virtio/virtio_ring.c:874 [inline]
 virtqueue_disable_cb+0x7a/0x150 drivers/virtio/virtio_ring.c:2570
 start_xmit+0x103/0x17a0 drivers/net/virtio_net.c:3362
 __netdev_start_xmit include/linux/netdevice.h:5219 [inline]
 netdev_start_xmit include/linux/netdevice.h:5228 [inline]
 xmit_one net/core/dev.c:3827 [inline]
 dev_hard_start_xmit+0x122/0x3e0 net/core/dev.c:3843
 sch_direct_xmit+0x192/0x550 net/sched/sch_generic.c:344
 __dev_xmit_skb net/core/dev.c:4102 [inline]
 __dev_queue_xmit+0xe9a/0x2000 net/core/dev.c:4679
 dev_queue_xmit include/linux/netdevice.h:3358 [inline]
 neigh_hh_output include/net/neighbour.h:531 [inline]
 neigh_output include/net/neighbour.h:545 [inline]
 ip_finish_output2+0x77f/0x8b0 net/ipv4/ip_output.c:235
 __ip_finish_output net/ipv4/ip_output.c:-1 [inline]
 ip_finish_output+0x114/0x2a0 net/ipv4/ip_output.c:323
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip_output+0xbd/0x190 net/ipv4/ip_output.c:436
 dst_output include/net/dst.h:461 [inline]
 ip_local_out net/ipv4/ip_output.c:129 [inline]
 __ip_queue_xmit+0xb4b/0xb80 net/ipv4/ip_output.c:532
 ip_queue_xmit+0x39/0x50 net/ipv4/ip_output.c:546
 __tcp_transmit_skb+0x1641/0x1a60 net/ipv4/tcp_output.c:1479
 tcp_transmit_skb net/ipv4/tcp_output.c:1497 [inline]
 tcp_write_xmit+0x1210/0x2fd0 net/ipv4/tcp_output.c:2833
 __tcp_push_pending_frames+0x6d/0x1b0 net/ipv4/tcp_output.c:3016
 tcp_push_pending_frames include/net/tcp.h:2173 [inline]
 tcp_data_snd_check net/ipv4/tcp_input.c:5666 [inline]
 tcp_rcv_established+0xa7f/0xf50 net/ipv4/tcp_input.c:6218
 tcp_v4_do_rcv+0x672/0x740 net/ipv4/tcp_ipv4.c:1926
 tcp_v4_rcv+0x1bd5/0x1f70 net/ipv4/tcp_ipv4.c:2368
 ip_protocol_deliver_rcu+0x397/0x780 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x1fc/0x2f0 net/ipv4/ip_input.c:239
 NF_HOOK include/linux/netfilter.h:318 [inline]
 ip_local_deliver+0xe8/0x1c0 net/ipv4/ip_input.c:260
 dst_input include/net/dst.h:471 [inline]
 ip_sublist_rcv_finish net/ipv4/ip_input.c:585 [inline]
 ip_list_rcv_finish net/ipv4/ip_input.c:634 [inline]
 ip_sublist_rcv+0x58e/0x670 net/ipv4/ip_input.c:642
 ip_list_rcv+0x261/0x290 net/ipv4/ip_input.c:676
 __netif_receive_skb_list_ptype net/core/dev.c:6022 [inline]
 __netif_receive_skb_list_core+0x4dc/0x500 net/core/dev.c:6069
 __netif_receive_skb_list net/core/dev.c:6121 [inline]
 netif_receive_skb_list_internal+0x487/0x600 net/core/dev.c:6212
 gro_normal_list include/net/gro.h:532 [inline]
 gro_flush_normal include/net/gro.h:540 [inline]
 napi_complete_done+0x1a3/0x410 net/core/dev.c:6581
 virtqueue_napi_complete drivers/net/virtio_net.c:766 [inline]
 virtnet_poll+0x1843/0x1cb0 drivers/net/virtio_net.c:3118
 __napi_poll+0x66/0x310 net/core/dev.c:7489
 napi_poll net/core/dev.c:7552 [inline]
 net_rx_action+0x391/0x830 net/core/dev.c:7679
 handle_softirqs+0xb7/0x290 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0x3a/0xc0 kernel/softirq.c:680
 common_interrupt+0x83/0x90 arch/x86/kernel/irq.c:285
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
 kcsan_setup_watchpoint+0x415/0x430 kernel/kcsan/core.c:705
 check_access kernel/kcsan/core.c:753 [inline]
 __tsan_memset+0x1da/0x1f0 kernel/kcsan/core.c:1335
 iov_iter_init lib/iov_iter.c:167 [inline]
 __import_iovec+0x2e1/0x540 lib/iov_iter.c:1489
 import_iovec+0x61/0x80 lib/iov_iter.c:1523
 copy_msghdr_from_user net/socket.c:2551 [inline]
 recvmsg_copy_msghdr net/socket.c:2800 [inline]
 ___sys_recvmsg+0x358/0x370 net/socket.c:2872
 do_recvmmsg+0x1ef/0x540 net/socket.c:2971
 __sys_recvmmsg net/socket.c:3045 [inline]
 __do_sys_recvmmsg net/socket.c:3068 [inline]
 __se_sys_recvmmsg net/socket.c:3061 [inline]
 __x64_sys_recvmmsg+0xe5/0x170 net/socket.c:3061
 x64_sys_call+0x27a6/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:300
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000 -> 0x0001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 19898 Comm: syz.6.5476 Not tainted 6.16.0-syzkaller-12245-g2988dfed8a5d #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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