From: Segher Boessenkool <segher@kernel.crashing.org>
To: Guohua Zhong <zhongguohua1@huawei.com>
Cc: wangle6@huawei.com, gregkh@linuxfoundation.org,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org, paulus@samba.org, nixiaoming@huawei.com
Subject: Re: Re：Re: [PATCH] powerpc: Fix a bug in __div64_32 if divisor is zero
Date: Sat, 22 Aug 2020 19:11:01 -0500 [thread overview]
Message-ID: <20200823001101.GO28786@gate.crashing.org> (raw)
In-Reply-To: <20200822165433.58228-1-zhongguohua1@huawei.com>
On Sun, Aug 23, 2020 at 12:54:33AM +0800, Guohua Zhong wrote:
> Yet, I have noticed that there is no checking of 'base' in these functions.
> But I am not sure how to check is better.As we know that the result is
> undefined when divisor is zero. It maybe good to print error and dump stack.
> Let the process to know that the divisor is zero by sending SIGFPE.
That is now what the PowerPC integer divide insns do: they just leave
the result undefined (and they can set the overflow flag then, but no
one uses that).
Segher
WARNING: multiple messages have this Message-ID (diff)
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Guohua Zhong <zhongguohua1@huawei.com>
Cc: christophe.leroy@csgroup.eu, nixiaoming@huawei.com,
wangle6@huawei.com, gregkh@linuxfoundation.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org,
paulus@samba.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: Re：Re: [PATCH] powerpc: Fix a bug in __div64_32 if divisor is zero
Date: Sat, 22 Aug 2020 19:11:01 -0500 [thread overview]
Message-ID: <20200823001101.GO28786@gate.crashing.org> (raw)
In-Reply-To: <20200822165433.58228-1-zhongguohua1@huawei.com>
On Sun, Aug 23, 2020 at 12:54:33AM +0800, Guohua Zhong wrote:
> Yet, I have noticed that there is no checking of 'base' in these functions.
> But I am not sure how to check is better.As we know that the result is
> undefined when divisor is zero. It maybe good to print error and dump stack.
> Let the process to know that the divisor is zero by sending SIGFPE.
That is now what the PowerPC integer divide insns do: they just leave
the result undefined (and they can set the overflow flag then, but no
one uses that).
Segher
next prev parent reply other threads:[~2020-08-23 0:13 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-20 13:10 [PATCH] powerpc: Fix a bug in __div64_32 if divisor is zero Guohua Zhong
2020-08-20 13:10 ` Guohua Zhong
2020-08-20 17:02 ` Christophe Leroy
2020-08-20 17:02 ` Christophe Leroy
2020-08-22 16:29 ` Guohua Zhong
2020-08-22 16:29 ` Guohua Zhong
2020-08-20 18:23 ` Christophe Leroy
2020-08-20 18:23 ` Christophe Leroy
2020-08-22 16:54 ` Re：Re: " Guohua Zhong
2020-08-22 16:54 ` Guohua Zhong
2020-08-22 17:25 ` Gabriel Paubert
2020-08-22 17:25 ` Gabriel Paubert
2020-08-24 13:25 ` Guohua Zhong
2020-08-24 13:25 ` Guohua Zhong
2020-08-24 15:05 ` David Laight
2020-08-24 15:05 ` David Laight
2020-08-23 0:11 ` Segher Boessenkool [this message]
2020-08-23 0:11 ` Segher Boessenkool
2020-08-24 11:54 ` Guohua Zhong
2020-08-24 11:54 ` Guohua Zhong
2020-08-24 18:17 ` Segher Boessenkool
2020-08-24 18:17 ` Segher Boessenkool
2020-08-22 16:06 ` Guohua Zhong
2020-08-22 16:06 ` Guohua Zhong
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