Re: Random guest crashes since 5c34d002dcc7 ("virtio_pci: use shared interrupts for virtqueues")

[Mike Galbraith <efault@gmx.de>]

On Mon, 2017-03-27 at 19:05 +0200, Christoph Hellwig wrote:
> Hi Mike,
> 
> does the patch below fix that issue for you?

Thanks, I'll give it a go in the A.M.

BTW, WRT RT woes with $subject, I tried booting a generic kernel with
threadirqs, and bingo, same deal, just a bit more painful than for RT,
where there's no watchdog moaning accompanying the (preemptible) spin.

[   28.346311] NMI watchdog: BUG: soft lockup - CPU#7 stuck for 22s! [kworker/7:1:108]
[   28.347536] Modules linked in: virtio_rng(E) virtio_blk(E) virtio_console(E) ata_piix(E) qxl(E) drm_kms_helper(E) syscopyarea(E) sysfillrect(E) sysimgblt(E) fb_sys_fops(E) ttm(E) ahci(E) libahci(E) drm(E) ehci_pci(E) uhci_hcd(E) ehci_hcd(E) usbcore(E) libata(E) virtio_pci(E) virtio_ring(E) virtio(E) 8139cp(E) floppy(E) mii(E) sg(E) scsi_mod(E) autofs4(E)
[   28.351160] CPU: 7 PID: 108 Comm: kworker/7:1 Tainted: G            E   4.11.0-default #30
[   28.352085] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20161202_174313-build11a 04/01/2014
[   28.353547] Workqueue: events control_work_handler [virtio_console]
[   28.354450] task: ffff8802370d4440 task.stack: ffffc900010d8000
[   28.355281] RIP: 0010:__send_control_msg+0xbd/0xd0 [virtio_console]
[   28.356005] RSP: 0018:ffffc900010dbd20 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff10
[   28.356987] RAX: 0000000000000000 RBX: ffff880231c31ec8 RCX: ffff880231cb1000
[   28.357866] RDX: 0000000000000001 RSI: ffffc900010dbd2c RDI: ffff880234f87400
[   28.358738] RBP: ffffc900010dbd78 R08: 0000000001080020 R09: ffffc900010dbd30
[   28.359718] R10: ffff88023fdddc00 R11: ffffffffffffffc8 R12: ffff880234f87400
[   28.360653] R13: ffff880231c31ea8 R14: 0000000000000001 R15: 0000000000000003
[   28.361510] FS:  0000000000000000(0000) GS:ffff88023fdc0000(0000) knlGS:0000000000000000
[   28.362433] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   28.363177] CR2: 00007f4da0f40000 CR3: 0000000001c09000 CR4: 00000000001406e0
[   28.363994] Call Trace:
[   28.364420]  add_port+0x23f/0x3d0 [virtio_console]
[   28.365094]  ? _raw_spin_unlock_irqrestore+0x24/0x40
[   28.365765]  handle_control_message.constprop.32+0x2c2/0x2e0 [virtio_console]
[   28.366622]  control_work_handler+0x52/0xb7 [virtio_console]
[   28.367291]  process_one_work+0x15c/0x440
[   28.367869]  worker_thread+0x137/0x4b0
[   28.368426]  kthread+0x10c/0x140
[   28.368921]  ? process_one_work+0x440/0x440
[   28.369477]  ? kthread_create_on_node+0x40/0x40
[   28.370067]  ret_from_fork+0x2c/0x40
[   28.370611] Code: 57 e1 48 83 c4 30 31 c0 5b 41 5c 41 5d 41 5e 41 5f 5d c3 4c 89 e7 e8 03 93 f7 ff eb 0e 4c 89 e7 e8 89 84 f7 ff 84 c0 75 d1 f3 90 <48> 8d 75 b4 4c 89 e7 e8 57 91 f7 ff 48 85 c0 74 e1 eb bc 0f 1f