From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Theodore Ts'o <tytso@mit.edu>,
Andreas Dilger <adilger.kernel@dilger.ca>,
linux-ext4@vger.kernel.org
Subject: Re: Aarch64 EXT4FS inode checksum failures - seems to be weak memory ordering issues
Date: Wed, 6 Jan 2021 17:46:05 +0000 [thread overview]
Message-ID: <20210106174605.GL1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <20210106172033.GA2165@willie-the-truck>
On Wed, Jan 06, 2021 at 05:20:34PM +0000, Will Deacon wrote:
> I've managed to reproduce the corruption on my AMD Seattle board (8x A57).
> I haven't had a chance to dig deeper yet, but here's the recipe which works
> for me:
>
> 1. I'm using GCC 4.9.4 simply to try to get as close as I can to rmk's
> setup. I don't know if this is necessary or not, but the toolchain is
> here:
>
> https://kernel.org/pub/tools/crosstool/files/bin/arm64/4.9.4/arm64-gcc-4.9.4-nolibc-aarch64-linux-gnu.tar.xz
>
> and I needed to pull down an old libmpfr to get cc1 to work:
>
> http://ports.ubuntu.com/pool/main/m/mpfr4/libmpfr4_3.1.2-1_arm64.deb
>
> 2. I build a 5.9 kernel with the config here:
>
> https://mirrors.edge.kernel.org/pub/linux/kernel/people/will/bugs/rmk/config-5.9.0
>
> and the resulting Image is here:
>
> https://mirrors.edge.kernel.org/pub/linux/kernel/people/will/bugs/rmk/Image-5.9.0
>
> 3. Using that kernel, I boot into a 64-bit Debian 10 filesystem and open a
> couple of terminals over SSH.
>
> 4. In one terminal, I run:
>
> $ while (true); do find /var /usr /bin /sbin -type f -print0 | xargs -0
> md5sum > /dev/null; echo 2 | sudo tee /proc/sys/vm/drop_caches; done
>
> (note that sudo will prompt you for a password on the first iteration)
>
> 5. In the other terminal, I run:
>
> $ while (true); do ./hackbench ; sleep 1; done
>
> where hackbench is built from:
>
> https://people.redhat.com/mingo/cfs-scheduler/tools/hackbench.c
>
> and compiled according to comment in the source code.
>
> With that, I see the following after ten seconds or so:
>
> EXT4-fs error (device sda2): ext4_lookup:1707: inode #674497: comm md5sum: iget: checksum invalid
>
> Russell, Mark -- does this recipe explode reliably for you too?
It took a couple of iterations of the find loop (4) here on a kernel
where I'd dropped BLK_WBT=y from my .config... whereas I wasn't able
to provoke it before. So running hackbench in parallel seems to
increase the probability.
I rebooted, set it going again, and on the first iteration it exploded
with ext4 inode checksum failure. And again on the following reboot.
So yes, it looks like you've found a way to more reliably reproduce
it.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
next prev parent reply other threads:[~2021-01-06 17:46 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-05 15:47 Aarch64 EXT4FS inode checksum failures - seems to be weak memory ordering issues Russell King - ARM Linux admin
2021-01-05 18:27 ` Darrick J. Wong
2021-01-05 19:50 ` Russell King - ARM Linux admin
2021-01-06 11:53 ` Mark Rutland
2021-01-06 12:13 ` Russell King - ARM Linux admin
2021-01-06 13:52 ` Russell King - ARM Linux admin
2021-01-06 17:20 ` Will Deacon
2021-01-06 17:46 ` Russell King - ARM Linux admin [this message]
2021-01-06 21:04 ` Arnd Bergmann
2021-01-06 22:00 ` Arnd Bergmann
2021-01-06 22:32 ` Russell King - ARM Linux admin
2021-01-07 11:18 ` Russell King - ARM Linux admin
2021-01-07 12:45 ` Russell King - ARM Linux admin
2021-01-07 13:16 ` Arnd Bergmann
2021-01-07 13:37 ` Russell King - ARM Linux admin
2021-01-07 16:27 ` Theodore Ts'o
2021-01-07 17:00 ` Florian Weimer
2021-01-07 21:48 ` Arnd Bergmann
2021-01-07 22:14 ` Russell King - ARM Linux admin
2021-01-07 22:41 ` Eric Biggers
2021-01-08 8:21 ` Ard Biesheuvel
2021-01-07 22:27 ` Eric Biggers
2021-01-07 23:53 ` Darrick J. Wong
2021-01-08 8:05 ` Arnd Bergmann
2021-01-08 9:13 ` Peter Zijlstra
2021-01-08 10:31 ` Pavel Machek
2021-01-07 21:20 ` Arnd Bergmann
2021-01-08 9:21 ` Peter Zijlstra
2021-01-08 9:26 ` Will Deacon
2021-01-08 20:02 ` Linus Torvalds
2021-01-08 20:22 ` Arnd Bergmann
2021-01-08 21:20 ` Nick Desaulniers
2021-01-08 20:29 ` Russell King - ARM Linux admin
2021-01-12 13:20 ` Lukas Wunner
2021-01-12 13:31 ` Florian Weimer
2021-01-12 13:46 ` David Laight
2021-01-12 17:28 ` Linus Torvalds
2021-01-14 13:13 ` Lukas Wunner
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