On Wed, Aug 14, 2024 at 02:25:00PM +0200, Jiri Pirko wrote: > From: Jiri Pirko <jiri@xxxxxxxxxx> > > During suspend/resume the following BUG was hit: > ------------[ cut here ]------------ > kernel BUG at lib/dynamic_queue_limits.c:99! > Internal error: Oops - BUG: 0 [#1] SMP ARM > Modules linked in: bluetooth ecdh_generic ecc libaes > CPU: 1 PID: 1282 Comm: rtcwake Not tainted > 6.10.0-rc3-00732-gc8bd1f7f3e61 #15240 > Hardware name: Generic DT based system > PC is at dql_completed+0x270/0x2cc > LR is at __free_old_xmit+0x120/0x198 > pc : [<c07ffa54>] lr : [<c0c42bf4>] psr: 80000013 > ... > Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none > Control: 10c5387d Table: 43a4406a DAC: 00000051 > ... > Process rtcwake (pid: 1282, stack limit = 0xfbc21278) > Stack: (0xe0805e80 to 0xe0806000) > ... > Call trace: > dql_completed from __free_old_xmit+0x120/0x198 > __free_old_xmit from free_old_xmit+0x44/0xe4 > free_old_xmit from virtnet_poll_tx+0x88/0x1b4 > virtnet_poll_tx from __napi_poll+0x2c/0x1d4 > __napi_poll from net_rx_action+0x140/0x2b4 > net_rx_action from handle_softirqs+0x11c/0x350 > handle_softirqs from call_with_stack+0x18/0x20 > call_with_stack from do_softirq+0x48/0x50 > do_softirq from __local_bh_enable_ip+0xa0/0xa4 > __local_bh_enable_ip from virtnet_open+0xd4/0x21c > virtnet_open from virtnet_restore+0x94/0x120 > virtnet_restore from virtio_device_restore+0x110/0x1f4 > virtio_device_restore from dpm_run_callback+0x3c/0x100 > dpm_run_callback from device_resume+0x12c/0x2a8 > device_resume from dpm_resume+0x12c/0x1e0 > dpm_resume from dpm_resume_end+0xc/0x18 > dpm_resume_end from suspend_devices_and_enter+0x1f0/0x72c > suspend_devices_and_enter from pm_suspend+0x270/0x2a0 > pm_suspend from state_store+0x68/0xc8 > state_store from kernfs_fop_write_iter+0x10c/0x1cc > kernfs_fop_write_iter from vfs_write+0x2b0/0x3dc > vfs_write from ksys_write+0x5c/0xd4 > ksys_write from ret_fast_syscall+0x0/0x54 > Exception stack(0xe8bf1fa8 to 0xe8bf1ff0) > ... > ---[ end trace 0000000000000000 ]--- > > After virtnet_napi_enable() is called, the following path is hit: > __napi_poll() > -> virtnet_poll() > -> virtnet_poll_cleantx() > -> netif_tx_wake_queue() > > That wakes the TX queue and allows skbs to be submitted and accounted by > BQL counters. > > Then netdev_tx_reset_queue() is called that resets BQL counters and > eventually leads to the BUG in dql_completed(). > > Move virtnet_napi_tx_enable() what does BQL counters reset before RX > napi enable to avoid the issue. > > Reported-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> > Closes: https://lore.kernel.org/netdev/e632e378-d019-4de7-8f13-07c572ab37a9@xxxxxxxxxxx/ > Fixes: c8bd1f7f3e61 ("virtio_net: add support for Byte Queue Limits") > Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> > Signed-off-by: Jiri Pirko <jiri@xxxxxxxxxx> Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > --- > drivers/net/virtio_net.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 3f10c72743e9..c6af18948092 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -2867,8 +2867,8 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index) > if (err < 0) > goto err_xdp_reg_mem_model; > > - virtnet_napi_enable(vi->rq[qp_index].vq, &vi->rq[qp_index].napi); > netdev_tx_reset_queue(netdev_get_tx_queue(vi->dev, qp_index)); > + virtnet_napi_enable(vi->rq[qp_index].vq, &vi->rq[qp_index].napi); > virtnet_napi_tx_enable(vi, vi->sq[qp_index].vq, &vi->sq[qp_index].napi); > > return 0; > -- > 2.45.2
