syzbot

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BUG: KCSAN: data-race in virtqueue_disable_cb / virtqueue_disable_cb

write to 0xffff888102701d88 of 2 bytes by interrupt on cpu 0:
 virtqueue_disable_cb_split drivers/virtio/virtio_ring.c:1047 [inline]
 virtqueue_disable_cb+0x75/0x2c0 drivers/virtio/virtio_ring.c:3108
 start_xmit+0x107/0x1a60 drivers/net/virtio_net.c:3344
 __netdev_start_xmit include/linux/netdevice.h:5368 [inline]
 netdev_start_xmit include/linux/netdevice.h:5377 [inline]
 xmit_one net/core/dev.c:3888 [inline]
 dev_hard_start_xmit+0x12a/0x3a0 net/core/dev.c:3904
 sch_direct_xmit+0x192/0x550 net/sched/sch_generic.c:372
 __dev_xmit_skb net/core/dev.c:4209 [inline]
 __dev_queue_xmit+0xdb9/0x1ec0 net/core/dev.c:4831
 dev_queue_xmit include/linux/netdevice.h:3418 [inline]
 neigh_hh_output include/net/neighbour.h:544 [inline]
 neigh_output include/net/neighbour.h:558 [inline]
 ip_finish_output2+0x705/0x8c0 net/ipv4/ip_output.c:237
 __ip_finish_output net/ipv4/ip_output.c:-1 [inline]
 ip_finish_output+0x112/0x290 net/ipv4/ip_output.c:325
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip_output+0xbd/0x1c0 net/ipv4/ip_output.c:438
 dst_output include/net/dst.h:470 [inline]
 ip_local_out net/ipv4/ip_output.c:131 [inline]
 __ip_queue_xmit+0xb68/0xba0 net/ipv4/ip_output.c:534
 ip_queue_xmit+0x39/0x50 net/ipv4/ip_output.c:548
 __tcp_transmit_skb+0x1c2a/0x20b0 net/ipv4/tcp_output.c:1715
 tcp_transmit_skb net/ipv4/tcp_output.c:1733 [inline]
 tcp_write_xmit+0x129e/0x36a0 net/ipv4/tcp_output.c:3061
 __tcp_push_pending_frames+0x6d/0x1b0 net/ipv4/tcp_output.c:3244
 tcp_push_pending_frames include/net/tcp.h:2360 [inline]
 tcp_data_snd_check net/ipv4/tcp_input.c:6075 [inline]
 tcp_rcv_established+0xc52/0x1320 net/ipv4/tcp_input.c:6658
 tcp_v4_do_rcv+0x3c5/0xa40 net/ipv4/tcp_ipv4.c:1851
 tcp_v4_rcv+0x18c9/0x1c10 net/ipv4/tcp_ipv4.c:2246
 ip_protocol_deliver_rcu+0x395/0x790 net/ipv4/ip_input.c:207
 ip_local_deliver_finish+0x1fc/0x2f0 net/ipv4/ip_input.c:241
 NF_HOOK include/linux/netfilter.h:318 [inline]
 ip_local_deliver+0xe8/0x1e0 net/ipv4/ip_input.c:262
 dst_input include/net/dst.h:480 [inline]
 ip_sublist_rcv_finish net/ipv4/ip_input.c:623 [inline]
 ip_list_rcv_finish net/ipv4/ip_input.c:675 [inline]
 ip_sublist_rcv+0x5a4/0x6a0 net/ipv4/ip_input.c:683
 ip_list_rcv+0x261/0x290 net/ipv4/ip_input.c:717
 __netif_receive_skb_list_ptype net/core/dev.c:6245 [inline]
 __netif_receive_skb_list_core+0x4dc/0x500 net/core/dev.c:6292
 __netif_receive_skb_list net/core/dev.c:6344 [inline]
 netif_receive_skb_list_internal+0x47d/0x5f0 net/core/dev.c:6435
 gro_normal_list include/net/gro.h:523 [inline]
 gro_flush_normal include/net/gro.h:531 [inline]
 napi_complete_done+0x19c/0x3f0 net/core/dev.c:6803
 virtqueue_napi_complete drivers/net/virtio_net.c:740 [inline]
 virtnet_poll+0x1b33/0x1fc0 drivers/net/virtio_net.c:3021
 __napi_poll+0x61/0x300 net/core/dev.c:7733
 napi_poll net/core/dev.c:7796 [inline]
 net_rx_action+0x452/0x930 net/core/dev.c:7953
 handle_softirqs+0xb9/0x280 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x42/0xd0 kernel/softirq.c:735
 common_interrupt+0x83/0x90 arch/x86/kernel/irq.c:326
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688
 kcsan_setup_watchpoint+0x404/0x410 kernel/kcsan/core.c:705
 __copy_msghdr net/socket.c:2584 [inline]
 copy_msghdr_from_user net/socket.c:2631 [inline]
 recvmsg_copy_msghdr net/socket.c:2884 [inline]
 ___sys_recvmsg+0x1d2/0x3b0 net/socket.c:2956
 do_recvmmsg+0x1ef/0x560 net/socket.c:3055
 __sys_recvmmsg net/socket.c:3129 [inline]
 __do_sys_recvmmsg net/socket.c:3152 [inline]
 __se_sys_recvmmsg net/socket.c:3145 [inline]
 __x64_sys_recvmmsg+0xe5/0x170 net/socket.c:3145
 x64_sys_call+0x80f/0x3020 arch/x86/include/generated/asm/syscalls_64.h:300
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888102701d88 of 2 bytes by interrupt on cpu 1:
 virtqueue_disable_cb_split drivers/virtio/virtio_ring.c:1046 [inline]
 virtqueue_disable_cb+0x4c/0x2c0 drivers/virtio/virtio_ring.c:3108
 skb_xmit_done+0x67/0x1a0 drivers/net/virtio_net.c:774
 vring_interrupt+0x2d7/0x310 drivers/virtio/virtio_ring.c:3254
 __handle_irq_event_percpu+0x8b/0x480 kernel/irq/handle.c:209
 handle_irq_event_percpu kernel/irq/handle.c:246 [inline]
 handle_irq_event+0x64/0xf0 kernel/irq/handle.c:263
 handle_edge_irq+0x154/0x450 kernel/irq/chip.c:857
 generic_handle_irq_desc include/linux/irqdesc.h:186 [inline]
 handle_irq arch/x86/kernel/irq.c:262 [inline]
 call_irq_handler arch/x86/kernel/irq.c:-1 [inline]
 __common_interrupt+0x60/0xb0 arch/x86/kernel/irq.c:333
 common_interrupt+0x7e/0x90 arch/x86/kernel/irq.c:326
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688
 crng_make_state+0xc1/0x200 drivers/char/random.c:384
 _get_random_bytes+0x85/0x1b0 drivers/char/random.c:396
 get_random_bytes+0x1d/0x30 drivers/char/random.c:427
 eth_random_addr include/linux/etherdevice.h:239 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:827 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline]
 nsim_dev_trap_report_work+0x23c/0x640 drivers/net/netdevsim/dev.c:922
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0x4f0/0x9c0 kernel/workqueue.c:3397
 worker_thread+0x58a/0x780 kernel/workqueue.c:3478
 kthread+0x22a/0x280 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x0000 -> 0x0001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3219 Comm: kworker/u8:12 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound nsim_dev_trap_report_work
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