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From: Andy Shevchenko <andriy.shevchenko@linux•intel.com>
To: David Laight <David.Laight@ACULAB•COM>
Cc: Petr Mladek <pmladek@suse•com>,
	"linux-arch@vger•kernel.org" <linux-arch@vger•kernel.org>,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail•com>,
	Heiko Carstens <heiko.carstens@de•ibm.com>,
	"linux-s390@vger•kernel.org" <linux-s390@vger•kernel.org>,
	"linuxppc-dev@lists•ozlabs.org" <linuxppc-dev@lists•ozlabs.org>,
	Rasmus Villemoes <linux@rasmusvillemoes•dk>,
	"linux-kernel@vger•kernel.org" <linux-kernel@vger•kernel.org>,
	Steven Rostedt <rostedt@goodmis•org>,
	Michal Hocko <mhocko@suse•cz>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail•com>,
	Stephen Rothwell <sfr@ozlabs•org>,
	Linus Torvalds <torvalds@linux-foundation•org>,
	Martin Schwidefsky <schwidefsky@de•ibm.com>,
	"Tobin C . Harding" <me@tobin•cc>
Subject: Re: [PATCH] vsprintf: Do not break early boot with probing addresses
Date: Mon, 13 May 2019 12:13:20 +0300	[thread overview]
Message-ID: <20190513091320.GK9224@smile.fi.intel.com> (raw)
In-Reply-To: <096d6c9c17b3484484d9d9d3f3aa3a7c@AcuMS.aculab.com>

On Mon, May 13, 2019 at 08:52:41AM +0000, David Laight wrote:
> From: christophe leroy
> > Sent: 10 May 2019 18:35
> > Le 10/05/2019 à 18:24, Steven Rostedt a écrit :
> > > On Fri, 10 May 2019 10:42:13 +0200
> > > Petr Mladek <pmladek@suse•com> wrote:

> > >> -	if (probe_kernel_address(ptr, byte))
> > >> +	if ((unsigned long)ptr < PAGE_SIZE || IS_ERR_VALUE(ptr))
> > >>   		return "(efault)";
> 
> "efault" looks a bit like a spellling mistake for "default".

It's a special, thus it's in parenthesis, though somebody can be
misguided.

> > Usually, < PAGE_SIZE means NULL pointer dereference (via the member of a
> > struct)
> 
> Maybe the caller should pass in a short buffer so that you can return
> "(err-%d)"
> or "(null+%#x)" ?

In both cases it should be limited to the size of pointer (8 or 16
characters). Something like "(e:%4d)" would work for error codes.

The "(null)" is good enough by itself and already an established
practice..

-- 
With Best Regards,
Andy Shevchenko



  reply	other threads:[~2019-05-13  9:16 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-09 12:19 [PATCH] vsprintf: Do not break early boot with probing addresses Petr Mladek
2019-05-09 13:05 ` Andy Shevchenko
2019-05-09 13:13 ` Steven Rostedt
2019-05-09 14:06   ` Petr Mladek
2019-05-09 13:38 ` Michal Suchánek
2019-05-09 13:46   ` David Laight
2019-05-10 10:21     ` Michael Ellerman
2019-05-10  4:32 ` Sergey Senozhatsky
2019-05-10  4:47   ` Linus Torvalds
2019-05-10  5:07     ` Sergey Senozhatsky
2019-05-10  6:41       ` Michael Ellerman
2019-05-10  8:06       ` Petr Mladek
2019-05-10  8:16         ` Sergey Senozhatsky
2019-05-10  8:42           ` Petr Mladek
2019-05-10  8:51             ` Sergey Senozhatsky
2019-05-10 14:49             ` Petr Mladek
2019-05-10 16:24             ` Steven Rostedt
2019-05-10 16:32               ` Martin Schwidefsky
2019-05-10 16:40                 ` Steven Rostedt
2019-05-10 16:45                   ` Martin Schwidefsky
2019-05-13 12:24                   ` Petr Mladek
2019-05-10 16:41               ` Andy Shevchenko
2019-05-10 17:35               ` christophe leroy
2019-05-13  8:52                 ` David Laight
2019-05-13  9:13                   ` Andy Shevchenko [this message]
2019-05-13 12:42                     ` Petr Mladek
2019-05-13 14:15                       ` Steven Rostedt
2019-05-14  2:07                       ` Sergey Senozhatsky
2019-05-14  2:25                         ` Sergey Senozhatsky
2019-05-14  8:28                         ` David Laight
2019-05-14  9:02                           ` Geert Uytterhoeven
2019-05-14 18:37                             ` Steven Rostedt
2019-05-14 19:13                               ` Geert Uytterhoeven
2019-05-14 19:35                                 ` Steven Rostedt
2019-05-15  7:23                                   ` Geert Uytterhoeven
2019-05-15  7:53                                     ` Petr Mladek
2019-05-15  6:21                                 ` Sergey Senozhatsky
2019-05-15  7:35                               ` Petr Mladek
2019-05-15  9:00                                 ` David Laight

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