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From: Peter Zijlstra <peterz@infradead.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Nathan Chancellor <natechancellor@gmail.com>,
	clang-built-linux <clang-built-linux@googlegroups.com>,
	x86@kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Sedat Dilek <sedat.dilek@gmail.com>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: x86 - clang / objtool status
Date: Wed, 24 Jul 2019 09:47:32 +0200	[thread overview]
Message-ID: <20190724074732.GJ3402@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190724023946.yxsz5im22fz4zxrn@treble>

On Tue, Jul 23, 2019 at 09:43:24PM -0500, Josh Poimboeuf wrote:
> On Thu, Jul 18, 2019 at 10:40:09PM +0200, Thomas Gleixner wrote:
> 
> >   drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: .altinstr_replacement+0x86: redundant UACCESS disable
> 
> Looking at this one, I think I agree with objtool.
> 
> PeterZ, Linus, I know y'all discussed this code a few months ago.
> 
> __copy_from_user() already does a CLAC in its error path.  So isn't the
> user_access_end() redundant for the __copy_from_user() error path?

Hmm, is this a result of your c705cecc8431 ("objtool: Track original function across branches") ?

I'm thinking it might've 'overlooked' the CLAC in the error path before
(because it didn't have a related function) and now it sees it and
worries about it.

Then again, I'm not seeing this warning on my GCC builds; so what's
happening?

  reply	other threads:[~2019-07-24  7:47 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-18 20:40 x86 - clang / objtool status Thomas Gleixner
2019-07-18 20:58 ` Nathan Chancellor
2019-07-19  6:39   ` Thomas Gleixner
2019-07-19  7:00     ` Arnd Bergmann
2019-07-19  7:03     ` Nathan Chancellor
2019-07-24 16:57     ` Nick Desaulniers
2019-07-18 22:42 ` Nick Desaulniers
2019-07-19  6:44   ` Thomas Gleixner
2019-07-19 11:37 ` Sedat Dilek
2019-07-19 13:48   ` Sedat Dilek
2019-07-22 15:40     ` Sedat Dilek
2019-07-25  6:17       ` Sedat Dilek
2019-07-24  2:43 ` Josh Poimboeuf
2019-07-24  7:47   ` Peter Zijlstra [this message]
2019-07-24 12:37     ` Josh Poimboeuf
2019-07-24 12:55     ` Josh Poimboeuf
2019-07-24 13:35       ` Peter Zijlstra
2019-07-24 14:05         ` Josh Poimboeuf
2019-07-24 14:10         ` Peter Zijlstra
2019-07-24 16:48           ` [PATCH] objtool: Improve UACCESS coverage Peter Zijlstra
2019-07-24 16:54             ` Nathan Chancellor
2019-07-24 16:55             ` Nick Desaulniers
2019-07-24 18:30             ` Sedat Dilek
2019-07-24 18:32               ` Sedat Dilek
2019-07-24 16:52   ` x86 - clang / objtool status Peter Zijlstra
2019-07-24 17:22   ` Nick Desaulniers

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