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Message-ID: <b402098421927699db853e5e05fbb9d48fa24886.camel@xry111.site>
Subject: Re: [PATCH 04/47] LoongArch: Set _PAGE_DIRTY only if _PAGE_WRITE is
 set in {pmd,pte}_mkdirty()
From:   Xi Ruoyao <xry111@xry111.site>
To:     Huacai Chen <chenhuacai@loongson.cn>,
        Huacai Chen <chenhuacai@kernel.org>
Cc:     loongarch@lists.linux.dev, Xuefeng Li <lixuefeng@loongson.cn>,
        Guo Ren <guoren@kernel.org>, Xuerui Wang <kernel@xen0n.name>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        "David S . Miller" <davem@davemloft.net>,
        sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org, Peter Xu <peterx@redhat.com>
Date:   Thu, 17 Nov 2022 23:42:17 +0800
In-Reply-To: <b1707e1c04a6a9b91fd5f70ea012b5bcc764516e.camel@xry111.site>
References: <20221117042532.4064448-1-chenhuacai@loongson.cn>
         <b1707e1c04a6a9b91fd5f70ea012b5bcc764516e.camel@xry111.site>
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On Thu, 2022-11-17 at 21:59 +0800, Xi Ruoyao wrote:
> Hi Huacai,
>=20
> On Thu, 2022-11-17 at 12:25 +0800, Huacai Chen wrote:
> > Now {pmd,pte}_mkdirty() set _PAGE_DIRTY bit unconditionally, this cause=
s
> > random segmentation fault after commit 0ccf7f168e17bb7e ("mm/thp: carry
> > over dirty bit when thp splits on pmd").
>=20
> Hmm, the pte_mkdirty call is already removed in commit 624a2c94f5b7a081
> ("Partly revert \"mm/thp: carry over dirty bit when thp splits on
> pmd\"").
>=20
> Not sure if this issue is related to some random segfaults I've observed
> recently though.=C2=A0 My last kernel build contains 0ccf7f168e17bb7e but
> does not contain 624a2c94f5b7a081.

I can confirm this patch alone (without 624a2c94f5b7a081) fixes the
random segfaults I've recently encountered running GCC testsuite.

Link: https://gcc.gnu.org/pipermail/gcc/2022-November/239857.html
Tested-by: Xi Ruoyao <xry111@xry111.site>

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