On Thu, Sep 12, 2024 at 01:11:21AM -0700, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 7c6a3a65ace7 minmax: reduce min/max macro expansion in ato.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1608e49f980000 > kernel config: https://syzkaller.appspot.com/x/.config?x=1e7d02549be622b2 > dashboard link: https://syzkaller.appspot.com/bug?extid=8a02104389c2e0ef5049 > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/a1f7496fa21f/disk-7c6a3a65.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/f423739e51a9/vmlinux-7c6a3a65.xz > kernel image: https://storage.googleapis.com/syzbot-assets/b65a0f38cbd7/bzImage-7c6a3a65.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+8a02104389c2e0ef5049@xxxxxxxxxxxxxxxxxxxxxxxxx > > ================================================================== > BUG: KCSAN: data-race in virtqueue_disable_cb / vring_interrupt > > write to 0xffff88810285ef52 of 1 bytes by interrupt on cpu 0: > vring_interrupt+0x12b/0x180 drivers/virtio/virtio_ring.c:2591 Yes, it's racy! 2589: /* Just a hint for performance: so it's ok that this can be racy! */ 2590: if (vq->event) 2591: vq->event_triggered = true; Question: is there a way to annotate code to tell syzbot it's ok? > __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:247 [inline] > call_irq_handler arch/x86/kernel/irq.c:259 [inline] > __common_interrupt+0x58/0xe0 arch/x86/kernel/irq.c:285 > common_interrupt+0x7c/0x90 arch/x86/kernel/irq.c:278 > asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 > __preempt_count_dec_and_test arch/x86/include/asm/preempt.h:94 [inline] > __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] > _raw_spin_unlock_irq+0x2f/0x50 kernel/locking/spinlock.c:202 > process_one_work kernel/workqueue.c:3200 [inline] > process_scheduled_works+0x43b/0x9a0 kernel/workqueue.c:3312 > worker_thread+0x526/0x6e0 kernel/workqueue.c:3389 > kthread+0x1d1/0x210 kernel/kthread.c:389 > ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > read to 0xffff88810285ef52 of 1 bytes by interrupt on cpu 1: > virtqueue_disable_cb_split drivers/virtio/virtio_ring.c:892 [inline] > virtqueue_disable_cb+0x92/0x180 drivers/virtio/virtio_ring.c:2446 > start_xmit+0x14b/0x1260 drivers/net/virtio_net.c:3034 > __netdev_start_xmit include/linux/netdevice.h:4913 [inline] > netdev_start_xmit include/linux/netdevice.h:4922 [inline] > xmit_one net/core/dev.c:3580 [inline] > dev_hard_start_xmit+0x119/0x3f0 net/core/dev.c:3596 > sch_direct_xmit+0x1b0/0x580 net/sched/sch_generic.c:343 > __dev_xmit_skb net/core/dev.c:3809 [inline] > __dev_queue_xmit+0xf3d/0x1fe0 net/core/dev.c:4389 > dev_queue_xmit include/linux/netdevice.h:3105 [inline] > neigh_hh_output include/net/neighbour.h:526 [inline] > neigh_output include/net/neighbour.h:540 [inline] > ip_finish_output2+0x73d/0x8b0 net/ipv4/ip_output.c:235 > ip_finish_output+0x11a/0x2a0 net/ipv4/ip_output.c:323 > NF_HOOK_COND include/linux/netfilter.h:303 [inline] > ip_output+0xab/0x170 net/ipv4/ip_output.c:433 > dst_output include/net/dst.h:450 [inline] > ip_local_out net/ipv4/ip_output.c:129 [inline] > __ip_queue_xmit+0xbcc/0xbf0 net/ipv4/ip_output.c:535 > ip_queue_xmit+0x38/0x50 net/ipv4/ip_output.c:549 > __tcp_transmit_skb+0x15b0/0x1970 net/ipv4/tcp_output.c:1466 > tcp_transmit_skb net/ipv4/tcp_output.c:1484 [inline] > tcp_write_xmit+0x1273/0x31c0 net/ipv4/tcp_output.c:2829 > __tcp_push_pending_frames+0x6a/0x1a0 net/ipv4/tcp_output.c:3014 > tcp_push_pending_frames include/net/tcp.h:2106 [inline] > tcp_data_snd_check net/ipv4/tcp_input.c:5707 [inline] > tcp_rcv_established+0xa12/0xef0 net/ipv4/tcp_input.c:6141 > tcp_v4_do_rcv+0x662/0x740 net/ipv4/tcp_ipv4.c:1911 > tcp_v4_rcv+0x1b25/0x1ee0 net/ipv4/tcp_ipv4.c:2346 > ip_protocol_deliver_rcu+0x370/0x720 net/ipv4/ip_input.c:205 > ip_local_deliver_finish+0x17d/0x210 net/ipv4/ip_input.c:233 > NF_HOOK include/linux/netfilter.h:314 [inline] > ip_local_deliver+0xec/0x1d0 net/ipv4/ip_input.c:254 > dst_input include/net/dst.h:460 [inline] > ip_sublist_rcv_finish net/ipv4/ip_input.c:580 [inline] > ip_list_rcv_finish net/ipv4/ip_input.c:631 [inline] > ip_sublist_rcv+0x55a/0x640 net/ipv4/ip_input.c:639 > ip_list_rcv+0x25e/0x290 net/ipv4/ip_input.c:674 > __netif_receive_skb_list_ptype net/core/dev.c:5704 [inline] > __netif_receive_skb_list_core+0x4f0/0x520 net/core/dev.c:5752 > __netif_receive_skb_list net/core/dev.c:5804 [inline] > netif_receive_skb_list_internal+0x4e4/0x660 net/core/dev.c:5896 > gro_normal_list include/net/gro.h:515 [inline] > napi_complete_done+0x1cb/0x450 net/core/dev.c:6247 > virtqueue_napi_complete drivers/net/virtio_net.c:694 [inline] > virtnet_poll+0x1b73/0x1fd0 drivers/net/virtio_net.c:2826 > __napi_poll+0x63/0x3c0 net/core/dev.c:6772 > napi_poll net/core/dev.c:6841 [inline] > net_rx_action+0x3a1/0x7f0 net/core/dev.c:6963 > handle_softirqs+0xc3/0x280 kernel/softirq.c:554 > __do_softirq kernel/softirq.c:588 [inline] > invoke_softirq kernel/softirq.c:428 [inline] > __irq_exit_rcu kernel/softirq.c:637 [inline] > irq_exit_rcu+0x3e/0x90 kernel/softirq.c:649 > instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] > sysvec_apic_timer_interrupt+0x37/0x80 arch/x86/kernel/apic/apic.c:1043 > asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 > > value changed: 0x00 -> 0x01 > > Reported by Kernel Concurrency Sanitizer on: > CPU: 1 UID: 0 PID: 31238 Comm: syz.2.3839 Not tainted 6.11.0-rc7-syzkaller-00021-g7c6a3a65ace7 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 > ================================================================== > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > If the report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup
