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From: Johan Hovold <johan@kernel.org>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>,
	"Du, Changbin" <changbin.du@intel.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	gregkh@linuxfoundation.org, alex.elder@linaro.org,
	Johan Hovold <johan@kernel.org>,
	kbuild test robot <lkp@intel.com>,
	linux-arch@vger.kernel.org, michal.lkml@markovi.net,
	linux-kernel@vger.kernel.org, arnd@arndb.de,
	yamada.masahiro@socionext.com, lgirdwood@gmail.com,
	broonie@kernel.org, rdunlap@infradead.org, x86@kernel.org,
	linux@armlinux.org.uk, linux-sparse@vger.kernel.org,
	mingo@redhat.com, kbuild-all@01.org, akpm@linux-foundation.org,
	changbin.du@gmail.com, tglx@linutronix.de,
	linux-kbuild@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v5 2/4] kernel hacking: new config NO_AUTO_INLINE to disable compiler auto-inline optimizations
Date: Thu, 7 Jun 2018 11:18:16 +0200	[thread overview]
Message-ID: <20180607091816.GT13775@localhost> (raw)
In-Reply-To: <20180607091025.m7dfix3e2xbwx4cs@vireshk-i7>

On Thu, Jun 07, 2018 at 02:40:25PM +0530, Viresh Kumar wrote:
> On 07-06-18, 11:03, Bernd Petrovitsch wrote:
> > On Thu, 2018-06-07 at 14:08 +0530, Viresh Kumar wrote:
> > > On 07-06-18, 15:46, Du, Changbin wrote:
> > > > I think if the destination is not a null terminated string (If I understand your
> > > > description below), memcpy can be used to get rid of such warning. The warning
> > > > makes sense in general as explained in mannual. Thanks!
> > > 
> > > The destination should be a null terminated string eventually, but we first need
> > > to make sure src is a null terminated string.
> > 
> > Is there strnlen() or memchr() in the kernel?
> > Then check the source before copying it.
> 
> It would be extra work, but memchr can be used to work around this I believe.
> 
> @Johan ??

If you want to work around the warning and think you can do it in some
non-contrived way, then go for it.

Clearing the request buffer, checking for termination using strnlen, and
then using memcpy might not be too bad.

But after all, it is a false positive, so leaving things as they stand
is fine too.

Thanks,
Johan

WARNING: multiple messages have this Message-ID (diff)
From: johan@kernel.org (Johan Hovold)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v5 2/4] kernel hacking: new config NO_AUTO_INLINE to disable compiler auto-inline optimizations
Date: Thu, 7 Jun 2018 11:18:16 +0200	[thread overview]
Message-ID: <20180607091816.GT13775@localhost> (raw)
In-Reply-To: <20180607091025.m7dfix3e2xbwx4cs@vireshk-i7>

On Thu, Jun 07, 2018 at 02:40:25PM +0530, Viresh Kumar wrote:
> On 07-06-18, 11:03, Bernd Petrovitsch wrote:
> > On Thu, 2018-06-07 at 14:08 +0530, Viresh Kumar wrote:
> > > On 07-06-18, 15:46, Du, Changbin wrote:
> > > > I think if the destination is not a null terminated string (If I understand your
> > > > description below), memcpy can be used to get rid of such warning. The warning
> > > > makes sense in general as explained in mannual. Thanks!
> > > 
> > > The destination should be a null terminated string eventually, but we first need
> > > to make sure src is a null terminated string.
> > 
> > Is there strnlen() or memchr() in the kernel?
> > Then check the source before copying it.
> 
> It would be extra work, but memchr can be used to work around this I believe.
> 
> @Johan ??

If you want to work around the warning and think you can do it in some
non-contrived way, then go for it.

Clearing the request buffer, checking for termination using strnlen, and
then using memcpy might not be too bad.

But after all, it is a false positive, so leaving things as they stand
is fine too.

Thanks,
Johan

  reply	other threads:[~2018-06-07  9:18 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-05  8:13 [RESEND PATCH v5 0/4] kernel hacking: GCC optimization for better debug experience (-Og) changbin.du
2018-06-05  8:13 ` changbin.du at intel.com
2018-06-05  8:13 ` [PATCH v5 1/4] x86/mm: surround level4_kernel_pgt with #ifdef CONFIG_X86_5LEVEL...#endif changbin.du
2018-06-05  8:13   ` changbin.du at intel.com
2018-06-05  8:13 ` [PATCH v5 2/4] kernel hacking: new config NO_AUTO_INLINE to disable compiler auto-inline optimizations changbin.du
2018-06-05  8:13   ` changbin.du at intel.com
2018-06-05 21:21   ` kbuild test robot
2018-06-05 21:21     ` kbuild test robot
2018-06-05 21:21     ` kbuild test robot
2018-06-05 21:21     ` kbuild test robot
2018-06-06 13:57     ` Steven Rostedt
2018-06-06 13:57       ` Steven Rostedt
2018-06-06 14:26       ` Johan Hovold
2018-06-06 14:26         ` Johan Hovold
2018-06-06 18:26         ` Steven Rostedt
2018-06-06 18:26           ` Steven Rostedt
2018-06-07  4:17           ` Viresh Kumar
2018-06-07  4:17             ` Viresh Kumar
2018-06-07  7:46             ` Du, Changbin
2018-06-07  7:46               ` Du, Changbin
2018-06-07  8:38               ` Viresh Kumar
2018-06-07  8:38                 ` Viresh Kumar
2018-06-07  9:03                 ` Bernd Petrovitsch
2018-06-07  9:03                   ` Bernd Petrovitsch
2018-06-07  9:03                   ` Bernd Petrovitsch
2018-06-07  9:10                   ` Viresh Kumar
2018-06-07  9:10                     ` Viresh Kumar
2018-06-07  9:18                     ` Johan Hovold [this message]
2018-06-07  9:18                       ` Johan Hovold
2018-06-07  9:19                       ` Viresh Kumar
2018-06-07  9:19                         ` Viresh Kumar
2018-06-07 10:12                         ` Alex Elder
2018-06-07 10:12                           ` Alex Elder
2018-06-07 10:27                           ` Johan Hovold
2018-06-07 10:27                             ` Johan Hovold
2018-06-07 10:27                             ` Johan Hovold
2018-06-08 20:03                       ` Steven Rostedt
2018-06-08 20:03                         ` Steven Rostedt
2018-06-11 15:46                         ` Johan Hovold
2018-06-11 15:46                           ` Johan Hovold
2018-06-07  8:06             ` Johan Hovold
2018-06-07  8:06               ` Johan Hovold
2018-06-05 21:34   ` kbuild test robot
2018-06-05 21:34     ` kbuild test robot
2018-06-05 21:34     ` kbuild test robot
2018-06-05 21:34     ` kbuild test robot
2018-06-06 14:01     ` Steven Rostedt
2018-06-06 14:01       ` Steven Rostedt
2018-06-05  8:13 ` [PATCH v5 3/4] ARM: mm: fix build error in fix_to_virt with CONFIG_CC_OPTIMIZE_FOR_DEBUGGING changbin.du
2018-06-05  8:13   ` changbin.du at intel.com
2018-06-05  8:13 ` [PATCH v5 4/4] kernel hacking: new config CC_OPTIMIZE_FOR_DEBUGGING to apply GCC -Og optimization changbin.du
2018-06-05  8:13   ` changbin.du at intel.com
2018-06-10 10:44   ` kbuild test robot
2018-06-10 10:44     ` kbuild test robot
2018-06-10 10:44     ` kbuild test robot
2018-06-10 10:44     ` kbuild test robot
2018-06-10 15:49   ` kbuild test robot
2018-06-10 15:49     ` kbuild test robot
2018-06-10 15:49     ` kbuild test robot
2018-06-10 15:49     ` kbuild test robot
2018-06-11 16:00     ` Steven Rostedt
2018-06-11 16:00       ` Steven Rostedt
  -- strict thread matches above, loose matches on Subject: below --
2018-05-11  8:09 [PATCH v5 0/4] kernel hacking: GCC optimization for better debug experience (-Og) changbin.du
2018-05-11  8:09 ` [PATCH v5 2/4] kernel hacking: new config NO_AUTO_INLINE to disable compiler auto-inline optimizations changbin.du
2018-05-17 15:49   ` kbuild test robot
2018-05-17 15:49     ` kbuild test robot
2018-05-17 15:49     ` kbuild test robot
2018-05-17 17:58   ` kbuild test robot
2018-05-17 17:58     ` kbuild test robot
2018-05-17 17:58     ` kbuild test robot

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