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References: <20210927064300.624279-1-chenhuacai@loongson.cn>
 <20210927064300.624279-15-chenhuacai@loongson.cn> <YVkVeREEIy23yVFX@zeniv-ca.linux.org.uk>
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From:   Huacai Chen <chenhuacai@gmail.com>
Date:   Sun, 3 Oct 2021 17:09:38 +0800
Message-ID: <CAAhV-H5oex-q_Pq4ibhXzvoQTQORmi+O8waJQwEm6jyDJ=xF4A@mail.gmail.com>
Subject: Re: [PATCH V4 14/22] LoongArch: Add signal handling support
To:     Al Viro <viro@zeniv.linux.org.uk>
Cc:     Huacai Chen <chenhuacai@loongson.cn>,
        Arnd Bergmann <arnd@arndb.de>,
        Andy Lutomirski <luto@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        David Airlie <airlied@linux.ie>,
        Jonathan Corbet <corbet@lwn.net>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-arch <linux-arch@vger.kernel.org>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Xuefeng Li <lixuefeng@loongson.cn>,
        Yanteng Si <siyanteng@loongson.cn>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        Eric Biederman <ebiederm@xmission.com>
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Hi, Al,

On Sun, Oct 3, 2021 at 10:36 AM Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> On Mon, Sep 27, 2021 at 02:42:51PM +0800, Huacai Chen wrote:
> > This patch adds signal handling support for LoongArch.
>
> No matter what you get in regs[4] after sys_rt_sigreturn(),
> you should *NOT* treat it as restartable.  IOW, you need to set
> regs[0] to 0 in there (or in restore_sigcontext()).  See e.g.
> 653d48b22166 for details of similar bug on arm.
Thanks, regs[0] should be cleared here.

Huacai