netdev - Re: bisected: 4.18-rc* regression: x86-32 troubles (with timers?)

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Date:   Tue, 24 Jul 2018 09:11:29 +0300 (EEST)
From:   Meelis Roos <mroos@...ux.ee>
To:     Daniel Borkmann <daniel@...earbox.net>
cc:     Arnd Bergmann <arnd@...db.de>,
        Linux Kernel list <linux-kernel@...r.kernel.org>,
        Networking <netdev@...r.kernel.org>
Subject: Re: bisected: 4.18-rc* regression: x86-32 troubles (with timers?)

> >> I would be curious as well about that whether revert would make it
> >> work. What's the value of sysctl net.core.bpf_jit_enable ? Does it
> >> change anything if you set it to 0 (only interpreter) or 1 (JIT
> >> enabled). Seems a bit strange to me that bisect ended at this commit
> >> given the issue you have. The JIT itself was also new in this window
> >> fwiw. In any case some more debug info would be great to have.
> > 
> > net.core.bpf_jit_enable is 1.
> > 
> > Since it breaks bootup, I can not easily change the value at runtime (it 
> > would be postfactum). Do you mean changing the 
> > CONFIG_BPF_JIT_ALWAYS_ON=y option?
> 
> Yeah if you chance it to N, and don't have any fixed /etc/sysctl.conf
> setting, then you'll boot up with interpreter first (net.core.bpf_jit_enable
> as 0). Curious whether that works just fine for you.

Disabled CONFIG_BPF_JIT_ALWAYS_ON on v4.18-rc5 and it works, tested on 2 
bootups.

-- 
Meelis Roos (mroos@...ux.ee)