2017-12-22 10:28:56

by Dou Liyang

[permalink] [raw]
Subject: Re: PROBLEM: 4.15.0-rc3 APIC causes lockups on Core 2 Duo laptop

Hi Alexandru,

At 12/21/2017 10:23 AM, Alexandru Chirvasitu wrote:
> This might be more helpful. I ran another bisect with the following
> final log:
>
> ---
>
> git bisect start
> # bad: [d6ffc6ac83b1f9f12652d89b9cb5bcbfbea7796c] x86/vector: Respect affinity mask in irq descriptor
> git bisect bad d6ffc6ac83b1f9f12652d89b9cb5bcbfbea7796c
> # good: [e4ae4c8ea7c65f61fde29c689d148c8c9e05305a] Merge branch 'irq/core' into x86/apic
> git bisect good e4ae4c8ea7c65f61fde29c689d148c8c9e05305a
> # good: [4ef76eb6de734dc03a7f3b8f80884362364e6049] x86/apic: Get rid of the legacy irq data storage
> git bisect good 4ef76eb6de734dc03a7f3b8f80884362364e6049
> # good: [ba801640b10d87b1c4e26cbcbe414a001255404f] x86/vector: Compile SMP only code conditionally
> git bisect good ba801640b10d87b1c4e26cbcbe414a001255404f
> # good: [90ad9e2d91067983f3328e21b306323877e5f48a] x86/io_apic: Reevaluate vector configuration on activate()
> git bisect good 90ad9e2d91067983f3328e21b306323877e5f48a
> # bad: [4900be83602b6be07366d3e69f756c1959f4169a] x86/vector/msi: Switch to global reservation mode
> git bisect bad 4900be83602b6be07366d3e69f756c1959f4169a
> # bad: [2db1f959d9dc16035f2eb44ed5fdb2789b754d6a] x86/vector: Handle managed interrupts proper
> git bisect bad 2db1f959d9dc16035f2eb44ed5fdb2789b754d6a
> # first bad commit: [2db1f959d9dc16035f2eb44ed5fdb2789b754d6a] x86/vector: Handle managed interrupts proper

It's helpful to me. I tried it in QEmu with

(Intel(R) Core(TM)2 Duo CPU T7700 @ 2.40GHz)
but, can't reproduced the bug.

>
> ---
>
> That first bad commit 2db1f95 identified at the end is interesting:
> it's the only one I've tried through all of this that actually gives
> me a kernel panic when unadorned with kernel options (so unlike all of
> the others it fails to even drop me at a tty login prompt).
>
> I tried a number of things to fiddle with it: it boots fine with
> either nolapic or noapic. The former results in seeing a single cpu
> with lscpu, but the latter (noapic) seems to give me as much
> functionality as I'd need. I'm not seeing the issue noted before,

Because the "noapic" just disable the I/O APIC, but, the "nolapic" will
disable both the Local APIC and I/O APIC

> whereby noapic for 4.15.0-rc3 was somehow disabling my ethernet card.
>
> I hope this second bisect went down better than the last one..

Could you add "apic=debug" in the kernel command line, then, give me the
dmesg log?

Thanks,
dou.