Re: upstream kernel crashes

On 2022-08-15 13:53:31 -0700, Andres Freund wrote:

The reason the debug patch didn't change anything, and that my debug printk
didn't show, is that gcp uses the legacy paths...

If there were a bug in the legacy path, it'd explain why the problem only
shows on gcp, and not in other situations.

I'll queue testing the legacy path with the equivalent change.

Booting with the equivalent change, atop 5.19, in the legacy setup_vq()
reliably causes boot to hang:

[    0.718768] ACPI: button: Sleep Button [SLPF]
[    0.721989] ACPI: \_SB_.LNKC: Enabled at IRQ 11
[    0.722688] adebug: use legacy: 0
[    0.722724] virtio-pci 0000:00:03.0: virtio_pci: leaving for legacy driver
[    0.724286] adebug: probe modern: -19
[    0.727353] ACPI: \_SB_.LNKD: Enabled at IRQ 10
[    0.728719] adebug: use legacy: 0
[    0.728766] virtio-pci 0000:00:04.0: virtio_pci: leaving for legacy driver
[    0.730422] adebug: probe modern: -19
[    0.733552] ACPI: \_SB_.LNKA: Enabled at IRQ 10
[    0.734923] adebug: use legacy: 0
[    0.734957] virtio-pci 0000:00:05.0: virtio_pci: leaving for legacy driver
[    0.736426] adebug: probe modern: -19
[    0.739039] ACPI: \_SB_.LNKB: Enabled at IRQ 11
[    0.740350] adebug: use legacy: 0
[    0.740390] virtio-pci 0000:00:06.0: virtio_pci: leaving for legacy driver
[    0.742142] adebug: probe modern: -19
[    0.747627] adebug: legacy setup_vq
[    0.748243] virtio-pci 0000:00:05.0: adebug: legacy: not limiting queue size, only 256
[    0.751081] adebug: legacy setup_vq
[    0.751110] virtio-pci 0000:00:05.0: adebug: legacy: not limiting queue size, only 256
[    0.754028] adebug: legacy setup_vq
[    0.754059] virtio-pci 0000:00:05.0: adebug: legacy: not limiting queue size, only 1
[    0.757760] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
[    0.759135] 00:03: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A
[    0.760399] 00:04: ttyS1 at I/O 0x2f8 (irq = 3, base_baud = 115200) is a 16550A
[    0.761610] 00:05: ttyS2 at I/O 0x3e8 (irq = 6, base_baud = 115200) is a 16550A
[    0.762923] 00:06: ttyS3 at I/O 0x2e8 (irq = 7, base_baud = 115200) is a 16550A
[    0.764222] Non-volatile memory driver v1.3
[    0.768857] adebug: legacy setup_vq
[    0.768882] virtio-pci 0000:00:06.0: adebug: legacy: not limiting queue size, only 256
[    0.773002] Linux agpgart interface v0.103
[    0.775424] loop: module loaded
[    0.780513] adebug: legacy setup_vq
[    0.780538] virtio-pci 0000:00:03.0: adebug: legacy: limiting queue size from 8192 to 1024
[    0.784075] adebug: legacy setup_vq
[    0.784104] virtio-pci 0000:00:03.0: adebug: legacy: limiting queue size from 8192 to 1024
[    0.787073] adebug: legacy setup_vq
[    0.787101] virtio-pci 0000:00:03.0: adebug: legacy: limiting queue size from 8192 to 1024
[    0.790379] scsi host0: Virtio SCSI HBA
[    0.795968] Freeing initrd memory: 7236K

Greetings,

Andres Freund