syzbot


KCSAN: data-race in virtqueue_disable_cb / virtqueue_enable_cb_delayed (9)

Status: upstream: reported on 2025/03/04 21:52
Subsystems: virt
[Documentation on labels]
Reported-by: syzbot+efe683d57990864b8c8e@syzkaller.appspotmail.com
First crash: 7d12h, last: 7d12h
Discussions (2)
Title Replies (including bot) Last reply
[PATCH] virtio_ring: Fix data race when accessing the event_triggered field of vring_virtqueue 2 (2) 2025/03/12 01:11
[syzbot] [virt?] KCSAN: data-race in virtqueue_disable_cb / virtqueue_enable_cb_delayed (9) 0 (1) 2025/03/04 21:52
Similar bugs (8)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in virtqueue_disable_cb / virtqueue_enable_cb_delayed (3) virt 1 1668d 1668d 0/28 auto-closed as invalid on 2020/09/20 20:51
upstream KCSAN: data-race in virtqueue_disable_cb / virtqueue_enable_cb_delayed (5) virt 3 1011d 1061d 0/28 auto-closed as invalid on 2022/07/09 17:31
upstream KCSAN: data-race in virtqueue_disable_cb / virtqueue_enable_cb_delayed (2) virt 3 1841d 1913d 0/28 auto-closed as invalid on 2020/05/05 19:05
upstream KCSAN: data-race in virtqueue_disable_cb / virtqueue_enable_cb_delayed (8) virt 2 630d 649d 0/28 auto-obsoleted due to no activity on 2023/07/25 21:20
upstream KCSAN: data-race in virtqueue_disable_cb / virtqueue_enable_cb_delayed (6) virt 1 852d 852d 0/28 auto-obsoleted due to no activity on 2022/12/15 06:15
upstream KCSAN: data-race in virtqueue_disable_cb / virtqueue_enable_cb_delayed virt 2 1953d 1965d 0/28 closed as invalid on 2019/11/19 13:54
upstream KCSAN: data-race in virtqueue_disable_cb / virtqueue_enable_cb_delayed (7) virt 1 707d 707d 0/28 auto-obsoleted due to no activity on 2023/05/09 11:44
upstream KCSAN: data-race in virtqueue_disable_cb / virtqueue_enable_cb_delayed (4) virt 1 1575d 1555d 0/28 auto-closed as invalid on 2020/12/23 03:08

Sample crash report:
==================================================================
BUG: KCSAN: data-race in virtqueue_disable_cb / virtqueue_enable_cb_delayed

write to 0xffff8881025bc452 of 1 bytes by task 3288 on cpu 0:
 virtqueue_enable_cb_delayed+0x42/0x3c0 drivers/virtio/virtio_ring.c:2653
 start_xmit+0x230/0x1310 drivers/net/virtio_net.c:3264
 __netdev_start_xmit include/linux/netdevice.h:5151 [inline]
 netdev_start_xmit include/linux/netdevice.h:5160 [inline]
 xmit_one net/core/dev.c:3800 [inline]
 dev_hard_start_xmit+0x119/0x3f0 net/core/dev.c:3816
 sch_direct_xmit+0x1a9/0x580 net/sched/sch_generic.c:343
 __dev_xmit_skb net/core/dev.c:4039 [inline]
 __dev_queue_xmit+0xf6a/0x2090 net/core/dev.c:4615
 dev_queue_xmit include/linux/netdevice.h:3313 [inline]
 neigh_hh_output include/net/neighbour.h:523 [inline]
 neigh_output include/net/neighbour.h:537 [inline]
 ip_finish_output2+0x71d/0x880 net/ipv4/ip_output.c:236
 ip_finish_output+0x11a/0x2a0 net/ipv4/ip_output.c:324
 NF_HOOK_COND include/linux/netfilter.h:303 [inline]
 ip_output+0xab/0x170 net/ipv4/ip_output.c:434
 dst_output include/net/dst.h:459 [inline]
 ip_local_out net/ipv4/ip_output.c:130 [inline]
 __ip_queue_xmit+0xb2c/0xb50 net/ipv4/ip_output.c:528
 ip_queue_xmit+0x38/0x50 net/ipv4/ip_output.c:542
 __tcp_transmit_skb+0x15ca/0x19d0 net/ipv4/tcp_output.c:1471
 tcp_transmit_skb net/ipv4/tcp_output.c:1489 [inline]
 tcp_write_xmit+0x1217/0x3020 net/ipv4/tcp_output.c:2832
 __tcp_push_pending_frames+0x6a/0x1a0 net/ipv4/tcp_output.c:3015
 tcp_push+0x320/0x340 net/ipv4/tcp.c:751
 tcp_sendmsg_locked+0x21a1/0x26a0 net/ipv4/tcp.c:1326
 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1358
 inet_sendmsg+0x77/0xd0 net/ipv4/af_inet.c:851
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg+0x102/0x180 net/socket.c:733
 sock_write_iter+0x15e/0x1a0 net/socket.c:1137
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0x77b/0x920 fs/read_write.c:679
 ksys_write+0xe8/0x1b0 fs/read_write.c:731
 __do_sys_write fs/read_write.c:742 [inline]
 __se_sys_write fs/read_write.c:739 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:739
 x64_sys_call+0x287e/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881025bc452 of 1 bytes by interrupt on cpu 1:
 virtqueue_disable_cb_split drivers/virtio/virtio_ring.c:880 [inline]
 virtqueue_disable_cb+0x92/0x180 drivers/virtio/virtio_ring.c:2566
 skb_xmit_done+0x5f/0x140 drivers/net/virtio_net.c:777
 vring_interrupt+0x161/0x190 drivers/virtio/virtio_ring.c:2715
 __handle_irq_event_percpu+0x95/0x490 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+0x16d/0x5b0 kernel/irq/chip.c:831
 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
 handle_irq arch/x86/kernel/irq.c:249 [inline]
 call_irq_handler arch/x86/kernel/irq.c:261 [inline]
 __common_interrupt+0x58/0xe0 arch/x86/kernel/irq.c:287
 common_interrupt+0x7c/0x90 arch/x86/kernel/irq.c:280
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
 rep_movs_alternative+0x33/0x70 arch/x86/lib/copy_user_64.S:57
 copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline]
 raw_copy_from_user arch/x86/include/asm/uaccess_64.h:141 [inline]
 _inline_copy_from_user include/linux/uaccess.h:178 [inline]
 _copy_from_user+0x6f/0xa0 lib/usercopy.c:18
 copy_from_user include/linux/uaccess.h:212 [inline]
 copy_msghdr_from_user+0x54/0x2a0 net/socket.c:2503
 recvmsg_copy_msghdr net/socket.c:2759 [inline]
 ___sys_recvmsg net/socket.c:2831 [inline]
 do_recvmmsg+0x256/0x6d0 net/socket.c:2930
 __sys_recvmmsg net/socket.c:3004 [inline]
 __do_sys_recvmmsg net/socket.c:3027 [inline]
 __se_sys_recvmmsg net/socket.c:3020 [inline]
 __x64_sys_recvmmsg+0xe2/0x170 net/socket.c:3020
 x64_sys_call+0x2a9a/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:300
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x01 -> 0x00

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 4167 Comm: syz.0.259 Not tainted 6.14.0-rc5-syzkaller-00013-g99fa936e8e4f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/03/04 16:34 upstream 99fa936e8e4f c3901742 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in virtqueue_disable_cb / virtqueue_enable_cb_delayed
* Struck through repros no longer work on HEAD.