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Message-ID: <8900ac3f1ea2e9bf5e5dff21734ea5f8f284e761.camel@xry111.site>
Subject: Re: "random" segment faults in expect running GCC regression test
 on LoongArch
From: Xi Ruoyao <xry111@xry111.site>
To: gcc@gcc.gnu.org
Cc: Lulu Cheng <chenglulu@loongson.cn>, Wang Xuerui <i@xen0n.name>, Chenghua
 Xu <xuchenghua@loongson.cn>
Date: Thu, 17 Nov 2022 22:15:37 +0800
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On Wed, 2022-11-09 at 15:43 +0800, Xi Ruoyao wrote:
> Hi,
>=20
> This is a "help wanted" message.=C2=A0 When I run GCC regression test on
> loongarch64-linux-gnu, expect occasionally crashes with a segment fault.
> The stack backtrace is like:

/* snip */

> The crashes happen on both my own LoongArch board and
> gcc401.fsffrance.org.=C2=A0 So I don't think it was an "only me" problem.
>=20
> The segment fault is not deterministic.=C2=A0 A Expect command like
>=20
> cd /path/to/gcc/build/gcc
> expect -- /usr/share/dejagnu/runtest.exp --tool gfortran dg.exp=3Dbind-c-=
contiguous-1.f90
>=20
> sometimes succeeds, sometimes immediately segfaults, sometimes prints
> several lines of strange error message and then exits abnormally.
>=20
> Usually I don't like to send "help wanted" messages, but this time I
> have no idea how to fix (or even triage) the problem.=C2=A0 I don't even =
know
> which component (Tcl? Expect? GCC? Glibc? Kernel?) I should blame.=C2=A0 =
So
> it seems I really need some help now...

I'm now 99% sure this is a kernel issue:

https://lore.kernel.org/loongarch/20221117042532.4064448-1-chenhuacai@loong=
son.cn/

--=20
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University