Re: linux-next: Tree for Aug 31 (new arm, arm64, s390 failures)

From: Guenter Roeck
Date: Mon Aug 31 2015 - 12:40:51 EST


Hi Marc,

On 08/31/2015 09:18 AM, Marc Zyngier wrote:
On Mon, 31 Aug 2015 08:47:07 -0700
Guenter Roeck <linux@xxxxxxxxxxxx> wrote:

Hi Marc,

On 08/31/2015 08:31 AM, Marc Zyngier wrote:
On Mon, 31 Aug 2015 07:17:36 -0700
Guenter Roeck <linux@xxxxxxxxxxxx> wrote:

Hi Guenter,

Qemu test results:
total: 85 pass: 74 fail: 11
Failed tests:
arm:vexpress-a9:arm_vexpress_defconfig:vexpress-v2p-ca9
arm:vexpress-a15:arm_vexpress_defconfig:vexpress-v2p-ca15-tc1
arm:vexpress-a9:multi_v7_defconfig:vexpress-v2p-ca9
arm:vexpress-a15:multi_v7_defconfig:vexpress-v2p-ca15-tc1
arm:realview-pb-a8:arm_realview_pb_defconfig
arm:realview-eb:arm_realview_eb_defconfig
mips:fuloong2e_defconfig
xtensa:dc232b:lx60:xtensa_defconfig
xtensa:dc232b:kc705:xtensa_defconfig
xtensa:dc233c:ml605:generic_kc705_defconfig
xtensa:dc233c:kc705:generic_kc705_defconfi

Notable new failures (since next-20150828) are the s390 build failures,
the arm64 build failure, and the arm qemu test failures.


[...]

The qemu arm tests all fail silently, meaning there is no console
output. Bisect points to 'irqchip/GIC: Convert to EOImode == 1'.
Bisect log attached.

Could you give me a qemu command-line I can use to track this down?
Real HW seems happy enough, from what I can see...


That is what I was most concerned about :-(. Unfortunately, it
affects many of the most widely used arm qemu emulations, so it
would be very desirable to get this fixed, either in the kernel
or in qemu.

See https://github.com/groeck/linux-build-test, specifically
https://github.com/groeck/linux-build-test/tree/master/rootfs/arm/.
run-qemu-arm.sh includes the various command lines and configurations.

Note that some of the tests require a patched version of qemu.
The tests failing above should all work with the latest published
version of qemu (2.4), though.

Please let me know if there is anything I can do to help tracking
this down.

I give it a quick go with qemu 2.1.2 as installed on my laptop, and the
results are interesting:

- With -next as of today, qemu segfaults. Humpffff.

- If I use my branch that contains the EOImode==1 patch, the system
boots normally.

So there is an interaction between this patch and whatever is in -next
at the moment, but that patch on its own is not what triggers the issue.

Looks like it.

I did a couple of tests.
- Revert 'irqchip/GIC: Don't deactivate interrupts forwarded to a guest'.
Same problem.
- Revert both 'irqchip/GIC: Don't deactivate interrupts forwarded to a guest'
and 'irqchip/GIC: Convert to EOImode == 1'.
Problem is no longer seen.

There are several other patches in drivers/irqchip/irq-gic.c since 4.2.

4c2880b31c70 irqchip/gic: Ensure gic_cpu_if_up/down() programs correct GIC instance
567e5a014848 irqchip/gic: Only allow the primary GIC to set the CPU map
4b979e4c611c Merge branch 'linus' into irq/core
0d3f2c92e004 irqchip/gic: Remove redundant gic_set_irqchip_flags
aec89ef72ba6 irqchip/gic: Enable SKIP_SET_WAKE and MASK_ON_SUSPEND
5b29264c659c irqchip: Use irq_desc_get_xxx() to avoid redundant lookup of irq_desc
4d83fcf8d615 irqchip/gic: Consolidate chained IRQ handler install/remove
41a83e06e2bb irqchip: Prepare for local stub header removal

Maybe there is an interaction between those and your patch ?

I need to build a more recent version of qemu, but the above doesn't
fill be with confidence...

My patched version of qemu 2.4 doesn't crash for me, it simply hangs.
Not that this is much better.

Thanks,
Guenter

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