Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Wed, 12 Oct 2022 10:45:46 -0600
From:   "Jason A. Donenfeld" <Jason@zx2c4.com>
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     Michael Ellerman <mpe@ellerman.id.au>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        ajd@linux.ibm.com, aneesh.kumar@linux.ibm.com,
        atrajeev@linux.vnet.ibm.com, christophe.leroy@csgroup.eu,
        cuigaosheng1@huawei.com, david@redhat.com, farosas@linux.ibm.com,
        geoff@infradead.org, gustavoars@kernel.org, haren@linux.ibm.com,
        hbathini@linux.ibm.com, joel@jms.id.au, lihuafei1@huawei.com,
        linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        lukas.bulwahn@gmail.com, mikey@neuling.org, nathan@kernel.org,
        nathanl@linux.ibm.com, nicholas@linux.ibm.com, npiggin@gmail.com,
        pali@kernel.org, paul@paul-moore.com, rmclure@linux.ibm.com,
        ruscur@russell.cc, windhl@126.com,
        wsa+renesas@sang-engineering.com, ye.xingchen@zte.com.cn,
        yuanjilin@cdjrlc.com, zhengyongjun3@huawei.com
Subject: Re: [GIT PULL] Please pull powerpc/linux.git powerpc-6.1-1 tag
Message-ID: <Y0bvOreqH2BdyVqt@zx2c4.com>
References: <87edvhntv0.fsf@mpe.ellerman.id.au>
 <20221012141827.GA2405914@roeck-us.net>
 <Y0biBtCUtc2mowbQ@zx2c4.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <Y0biBtCUtc2mowbQ@zx2c4.com>
Precedence: bulk

On Wed, Oct 12, 2022 at 09:49:26AM -0600, Jason A. Donenfeld wrote:
> On Wed, Oct 12, 2022 at 07:18:27AM -0700, Guenter Roeck wrote:
> > NIP [c000000000031630] .replay_soft_interrupts+0x60/0x300
> > LR [c000000000031964] .arch_local_irq_restore+0x94/0x1c0
> > Call Trace:
> > [c000000007df3870] [c000000000031964] .arch_local_irq_restore+0x94/0x1c0 (unreliable)
> > [c000000007df38f0] [c000000000f8a444] .__schedule+0x664/0xa50
> > [c000000007df39d0] [c000000000f8a8b0] .schedule+0x80/0x140
> > [c000000007df3a50] [c00000000092f0dc] .try_to_generate_entropy+0x118/0x174
> > [c000000007df3b40] [c00000000092e2e4] .urandom_read_iter+0x74/0x140
> > [c000000007df3bc0] [c0000000003b0044] .vfs_read+0x284/0x2d0
> > [c000000007df3cd0] [c0000000003b0d2c] .ksys_read+0xdc/0x130
> > [c000000007df3d80] [c00000000002a88c] .system_call_exception+0x19c/0x330
> > [c000000007df3e10] [c00000000000c1d4] system_call_common+0xf4/0x258
> 
> Obviously the first couple lines of this concern me a bit. But I think
> actually this might just be a catalyst for another bug. You could view
> that function as basically just:
> 
>     while (something)
>     	schedule();
> 
> And I guess in the process of calling the scheduler a lot, which toggles
> interrupts a lot, something got wedged.
> 
> Curious, though, I did try to reproduce this, to no avail. My .config is
> https://xn--4db.cc/rBvHWfDZ . What's yours?

I also just tried using your github linux-build-test scripts as a guide
for construction a config -- https://xn--4db.cc/B0HpEQDQ -- and loaded
up your rootfs over sdhci and such, and still couldn't manage to
reproduce. I tried commenting out the line "if (!bits)" in
_credit_init_bits(), so that the rng would never initialize, so that the
schedule() loop would just keep on running indefinitely, but still no
dice.

But also, I'm running Linus' tree. From your log, I see
"6.0.0-rc2-00163-ga5edf9815dd7". So maybe these bugs got fixed
elsewhere?

Jason