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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Sumit Garg <sumit.garg@linaro.org>
Cc: Cengiz Can <cengiz@kernel.wtf>,
	Daniel Thompson <daniel.thompson@linaro.org>,
	Douglas Anderson <dianders@chromium.org>,
	Jason Wessel <jason.wessel@windriver.com>,
	kgdb-bugreport@lists.sourceforge.net,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Petr Mladek <pmladek@suse.com>
Subject: Re: [PATCH v3] kdb: remove unnecessary null check of dbg_io_ops
Date: Tue, 30 Jun 2020 14:48:53 +0300	[thread overview]
Message-ID: <20200630114853.GS3703480@smile.fi.intel.com> (raw)
In-Reply-To: <CAFA6WYPDTKQ4cm+TMmRt+qDiF+s3gggCsW1gfzCaaOdP9rJgdQ@mail.gmail.com>

On Tue, Jun 30, 2020 at 05:06:31PM +0530, Sumit Garg wrote:
> On Tue, 30 Jun 2020 at 14:00, Cengiz Can <cengiz@kernel.wtf> wrote:
> >
> > `kdb_msg_write` operates on a global `struct kgdb_io *` called
> > `dbg_io_ops`.
> >
> > It's initialized in `debug_core.c` and checked throughout the debug
> > flow.
> >
> > There's a null check in `kdb_msg_write` which triggers static analyzers
> > and gives the (almost entirely wrong) impression that it can be null.
> >
> > Coverity scanner caught this as CID 1465042.
> >
> > I have removed the unnecessary null check and eliminated false-positive
> > forward null dereference warning.

> > -               while (len--) {
> > -                       dbg_io_ops->write_char(*cp);
> > -                       cp++;
> > -               }
> > +       while (len--) {
> > +               dbg_io_ops->write_char(*cp);
> > +               cp++;
> >         }

Despite being in the original code this can be simple done in two lines:

	while (len--)
		dbg_io_ops->write_char(*cp++);

-- 
With Best Regards,
Andy Shevchenko



  reply	other threads:[~2020-06-30 11:48 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-29 13:59 [PATCH] kdb: prevent possible null deref in kdb_msg_write Cengiz Can
2020-06-29 14:27 ` Daniel Thompson
2020-06-29 14:50 ` Petr Mladek
2020-06-29 14:53   ` Petr Mladek
2020-06-29 15:37   ` Daniel Thompson
2020-06-29 20:50     ` [PATCH v2] kdb: remove unnecessary null check of dbg_io_ops Cengiz Can
2020-06-29 21:16       ` Doug Anderson
2020-06-29 22:10         ` Cengiz Can
2020-06-30  5:55     ` [PATCH] kdb: prevent possible null deref in kdb_msg_write Sumit Garg
2020-06-30  8:29       ` [PATCH v3] kdb: remove unnecessary null check of dbg_io_ops Cengiz Can
2020-06-30 11:36         ` Sumit Garg
2020-06-30 11:48           ` Andy Shevchenko [this message]
2020-06-30 22:32         ` Doug Anderson
2020-07-10 12:15           ` Cengiz Can
2020-07-10 13:41             ` Daniel Thompson

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