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From: Szabolcs Nagy <szabolcs.nagy@arm.com>
To: Richard Henderson <richard.henderson@linaro.org>
Cc: nd@arm.com, qemu-devel@nongnu.org
Subject: Re: tst-arm-mte bug: PSTATE.TCO is cleared on exceptions
Date: Mon, 18 May 2020 13:59:01 +0100	[thread overview]
Message-ID: <20200518125901.GI27289@arm.com> (raw)
In-Reply-To: <5d0ae4c0-70a8-255c-9493-ca8b65e572fb@linaro.org>

The 05/07/2020 10:21, Richard Henderson wrote:
> A reproducer would be most helpful.
> 
> Something that can help is saving a VM snapshot with the kernel booted and the
> user logged in, just ready to run the test program.  Then you can get back to
> exactly the state you want before things go wrong, even with a different qemu
> build.

i got some time to create a reproducer (with public code),
temporarily hosting the binaries at

http://port70.net/~nsz/tmp/qemu-bug.tar.gz
~251M

here

echo ./bug.sh | ./qemu-bug.sh

crashes in about 1 minute (where qemu-bug.sh
loads a snapshot with root shell and ./bug.sh
triggers the bug)

the disk rootfs is based on
https://distfiles.adelielinux.org/adelie/1.0/iso/rc1/adelie-rootfs-aarch64-1.0-rc1-20200206.txz
the kernel Image is linux mte-v3 with reverting the commit
"arm64: mte: Check the DT memory nodes for MTE support"
qemu is static linked from the branch tgt-arm-mte.

the userspace workload that triggers the bug is using the
adelie linux package manager with a malloc with tagging.
(the malloc implementation is a modified version of
https://github.com/richfelker/mallocng-draft
the code is on the disk image, it has known issues, but
it should not crash qemu)

i will remove the file after a few days. hope this helps.


  reply	other threads:[~2020-05-18 13:18 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-20 10:29 tst-arm-mte bug: PSTATE.TCO is cleared on exceptions Szabolcs Nagy
2020-04-22  4:39 ` Richard Henderson
2020-04-24 19:47   ` Richard Henderson
2020-05-06 12:57     ` Szabolcs Nagy
2020-05-07  9:59       ` Szabolcs Nagy
2020-05-07 17:21         ` Richard Henderson
2020-05-18 12:59           ` Szabolcs Nagy [this message]
2020-05-19 18:46             ` Richard Henderson

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