From: Stephen Rothwell <sfr@canb•auug.org.au>
To: David Miller <davem@davemloft•net>
Cc: netdev@vger•kernel.org, linux-next@vger•kernel.org,
linux-kernel@vger•kernel.org, sd@queasysnail•net,
Linus Torvalds <torvalds@linux-foundation•org>
Subject: Re: linux-next: build warning after merge of the net tree
Date: Fri, 6 Dec 2019 10:48:23 +1100 [thread overview]
Message-ID: <20191206104823.36998638@canb.auug.org.au> (raw)
In-Reply-To: <20191205.145739.377846077558856039.davem@davemloft.net>
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Hi Dave,
On Thu, 05 Dec 2019 14:57:39 -0800 (PST) David Miller <davem@davemloft•net> wrote:
>
> I think it is a false positive as well. It looks like the compiler
> has trouble seeing through ptr error guards.
>
> In the new code the compiler can only see that the return value in the
> error case is non-zero, not necessarily that it is < 0 which is the
> guard against uninitialized accesses of 'obj'.
>
> It will satisfy this property, but through the various casts and
> implicit demotions, this information is lost on the compiler.
>
> My compiler didn't emit this warning FWIW.
>
> gcc (GCC) 8.3.1 20190223 (Red Hat 8.3.1-2)
>
> I'm unsure how to handle this, setting 'n' to explicitly be NULL
> is bogus because the compiler now will think that a NULL deref
> happens since the guard isn't guarding the existing assignment.
Yeah, not much we can do.
x86_64-linux-gnu-gcc (Debian 9.2.1-19) 9.2.1 20191109
--
Cheers,
Stephen Rothwell
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next prev parent reply other threads:[~2019-12-05 23:48 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-04 21:44 linux-next: build warning after merge of the net tree Stephen Rothwell
2019-12-05 22:57 ` David Miller
2019-12-05 23:48 ` Stephen Rothwell [this message]
-- strict thread matches above, loose matches on Subject: below --
2019-01-14 4:15 Stephen Rothwell
2018-08-21 22:04 Stephen Rothwell
2018-08-22 19:26 ` Cong Wang
2017-08-22 23:34 Stephen Rothwell
2017-06-13 11:08 Stephen Rothwell
2017-06-13 11:31 ` Ashwanth Goli
2017-01-18 22:56 Stephen Rothwell
2017-01-19 8:26 ` Tariq Toukan
2014-09-18 0:32 Stephen Rothwell
2014-09-18 0:35 ` Randy Dunlap
2014-09-23 14:59 ` Michal Marek
2014-09-23 21:23 ` Stephen Rothwell
2014-09-24 0:36 ` Stephen Rothwell
2014-09-24 1:58 ` David Miller
2011-05-13 1:41 Stephen Rothwell
2011-05-13 3:04 ` David Miller
2011-05-09 3:46 Stephen Rothwell
2011-05-09 4:13 ` David Miller
2010-07-22 2:11 Stephen Rothwell
2010-07-22 4:09 ` David Miller
2010-07-07 4:30 Stephen Rothwell
2010-07-08 1:23 ` David Miller
2010-07-06 4:25 Stephen Rothwell
2010-07-08 0:45 ` David Miller
2010-07-08 1:18 ` David Miller
2010-07-08 4:13 ` Joe Perches
2010-07-11 2:52 ` David Miller
2010-08-31 2:57 ` Stephen Rothwell
2010-08-31 3:14 ` Joe Perches
2010-08-31 3:58 ` Stephen Rothwell
2010-08-31 4:03 ` Joe Perches
2010-08-31 4:46 ` David Miller
2010-08-31 4:45 ` David Miller
2010-08-31 4:42 ` David Miller
2010-03-01 5:47 Stephen Rothwell
2010-03-01 7:02 ` David Miller
2010-02-15 3:32 Stephen Rothwell
2010-02-15 6:21 ` David Miller
2010-02-15 6:51 ` David Miller
2010-02-15 9:36 ` Jiri Pirko
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