linux-kernel - Re: [RESEND PATCH V2] arm64: fault: avoid send SIGBUS two times

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Message-ID: <316b5416-1268-1e9b-ae07-aa6cd31db8a8@huawei.com>
Date:   Tue, 12 Dec 2017 11:31:15 +0800
From:   Xie XiuQi <xiexiuqi@...wei.com>
To:     Dongjiu Geng <gengdongjiu@...wei.com>, <catalin.marinas@....com>,
        <will.deacon@....com>, <james.morse@....com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <huangshaoyu@...wei.com>,
        <wuquanming@...wei.com>, <linuxarm@...wei.com>
Subject: Re: [RESEND PATCH V2] arm64: fault: avoid send SIGBUS two times

Hi Dongjiu,

On 2017/12/12 0:05, Dongjiu Geng wrote:
> do_sea() calls arm64_notify_die() which will always signal
> user-space. It also returns whether APEI claimed the external
> abort as a RAS notification. If it returns failure do_mem_abort()
> will signal user-space too.
> 
> do_mem_abort() wants to know if we handled the error, we always
> call arm64_notify_die() so can always return success.
> 
> Signed-off-by: Dongjiu Geng <gengdongjiu@...wei.com>
> ---
> 1. Address James's comments to update the commit messages
> 2. Address James's comments to not change the si_code for SIGBUS
> ---
>  arch/arm64/mm/fault.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
> index b64958b..38b9f3e 100644
> --- a/arch/arm64/mm/fault.c
> +++ b/arch/arm64/mm/fault.c
> @@ -610,7 +610,6 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
>  {
>  	struct siginfo info;
>  	const struct fault_info *inf;
> -	int ret = 0;
>  
>  	inf = esr_to_fault_info(esr);
>  	pr_err("Synchronous External Abort: %s (0x%08x) at 0x%016lx\n",
> @@ -625,7 +624,7 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
>  		if (interrupts_enabled(regs))
>  			nmi_enter();
>  
> -		ret = ghes_notify_sea();
> +		ghes_notify_sea();
>  
>  		if (interrupts_enabled(regs))
>  			nmi_exit();
> @@ -640,7 +639,7 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
>  		info.si_addr  = (void __user *)addr;
>  	arm64_notify_die("", regs, &info, esr);
>  
> -	return ret;
> +	return 0;

It looks good to me. do_sea() has done all necessary action for SEA, so it should always return 0,
no matter ghes_notify_sea() return true or false.

Reviewed-by: Xie XiuQi <xiexiuqi@...wei.com>

>  }
>  
>  static const struct fault_info fault_info[] = {
> --
> 2.10.1
> 

-- 
Thanks,
Xie XiuQi