From: Uladzislau Rezki <urezki@gmail.com>
To: Daniel Axtens <dja@axtens.net>
Cc: rcu@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: powerpc 5.10-rcN boot failures with RCU_SCALE_TEST=m
Date: Fri, 27 Nov 2020 17:41:28 +0100 [thread overview]
Message-ID: <20201127164128.GA47008@pc638.lan> (raw)
In-Reply-To: <87eekfh80a.fsf@dja-thinkpad.axtens.net>
> Hi all,
>
> I'm having some difficulty tracking down a bug.
>
> Some configurations of the powerpc kernel since somewhere in the 5.10
> merge window fail to boot on some ppc64 systems. They hang while trying
> to bring up SMP. It seems to depend on the RCU_SCALE/PERF_TEST option.
> (It was renamed in the 5.10 merge window.)
>
> I can reproduce it as follows with qemu tcg:
>
> make -j64 pseries_le_defconfig
> scripts/config -m RCU_SCALE_TEST
> scripts/config -m RCU_PERF_TEST
> make -j 64 vmlinux CC="ccache gcc"
>
> qemu-system-ppc64 -cpu power9 -M pseries -m 1G -nographic -vga none -smp 4 -kernel vmlinux
>
> ...
> [ 0.036284][ T0] Mount-cache hash table entries: 8192 (order: 0, 65536 bytes, linear)
> [ 0.036481][ T0] Mountpoint-cache hash table entries: 8192 (order: 0, 65536 bytes, linear)
> [ 0.148168][ T1] POWER9 performance monitor hardware support registered
> [ 0.151118][ T1] rcu: Hierarchical SRCU implementation.
> [ 0.186660][ T1] smp: Bringing up secondary CPUs ...
> <hangs>
>
I am not sure if that is helpful but i checked it on my x86_64 system
using the cross compiled for powerpc Linux kernel:
<snip>
urezki@pc638:~/data/coding/linux-rcu.git$ powerpc64-linux-gnu-gcc
--version
powerpc64-linux-gnu-gcc (Debian 8.3.0-2) 8.3.0
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is
NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.
urezki@pc638:~/data/coding/linux-rcu.git$
<snip>
with ARCH=powerpc make -j64 pseries_defconfig configuration. I used the 5.10.0-rc1 kernel.
<snip>
urezki@pc638:~/data/coding/linux-rcu.git$ qemu-system-ppc64 --version
QEMU emulator version 3.1.0 (Debian 1:3.1+dfsg-8+deb10u8)
Copyright (c) 2003-2018 Fabrice Bellard and the QEMU Project developers
urezki@pc638:~/data/coding/linux-rcu.git$
<snip>
On my setup i can run the kernel with and without the modules which are
in question. So
qemu-system-ppc64 -cpu power9 -M pseries -m 1G -nographic -vga none -smp 4 -kernel ./vmlinux
works for both cases, with RCU_SCALE and without.
Just in case, maybe this information can be useful also.
--
Vlad Rezki
next prev parent reply other threads:[~2020-11-27 16:45 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-27 2:02 powerpc 5.10-rcN boot failures with RCU_SCALE_TEST=m Daniel Axtens
2020-11-27 15:50 ` Paul E. McKenney
2020-11-27 15:50 ` Paul E. McKenney
2020-11-27 16:41 ` Uladzislau Rezki [this message]
2020-12-02 14:03 ` Michael Ellerman
2020-12-02 14:39 ` Uladzislau Rezki
2020-12-02 14:39 ` Uladzislau Rezki
2020-12-03 6:22 ` Michael Ellerman
2020-12-03 6:22 ` Michael Ellerman
2020-12-03 14:34 ` Uladzislau Rezki
2020-12-03 14:34 ` Uladzislau Rezki
2020-12-04 20:23 ` Uladzislau Rezki
2020-12-04 20:23 ` Uladzislau Rezki
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