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From: <charley.ashbringer@gmail.com>
To: "'Matthew Wilcox'" <willy@infradead.org>,
	"'Randy Dunlap'" <rdunlap@infradead.org>
Cc: <keescook@chromium.org>, <mcgrof@kernel.org>,
	<yzaikin@google.com>, <linux-kernel@vger.kernel.org>,
	<linux-fsdevel@vger.kernel.org>
Subject: RE: [PATCH] sysctl: add bound to panic_timeout to prevent overflow
Date: Fri, 10 Jul 2020 18:28:45 -0400	[thread overview]
Message-ID: <0d4601d65709$7a0e2d80$6e2a8880$@gmail.com> (raw)
In-Reply-To: <20200710112803.GI12769@casper.infradead.org>

> On Thu, Jul 09, 2020 at 08:31:39PM -0700, Randy Dunlap wrote:
> > > +/* this is needed for setting boundery for panic_timeout to prevent
> > > +it from overflow*/
> >
> >                                  boundary (or max value)
overflow */
> >
> > > +static int panic_time_max = INT_MAX / 1000;
> 
> Or just simplify the comment.
> 
> /* Prevent overflow in panic() */
> 
> Or perhaps better, fix panic() to not overflow.
> 
> -		for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP)
{
> +		for (i = 0; i / 1000 < panic_timeout; i += PANIC_TIMER_STEP)
{
> 
> you probably also want to change i to be a long long or the loop may never
> terminate.

Thanks for the feedback, I too agree this should be better than 
modifying the sysctl, considering how localized and neat this
change is. It's also more readable. Setting a bound in sysctl.c
which is dependent on the constant value in panic.c is not a very
good idea.

I agree changing i from long to long long is necessary. 

I'll submit a v2 patch enforcing this shortly.

Cheers,
Changming


      reply	other threads:[~2020-07-10 22:28 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-10  3:22 Changming Liu
2020-07-10  3:31 ` Randy Dunlap
2020-07-10 11:28   ` Matthew Wilcox
2020-07-10 22:28     ` charley.ashbringer [this message]

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