From: Jakub Jelinek <jakub@redhat.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Fengguang Wu <fengguang.wu@intel.com>,
Richard Henderson <rth@twiddle.net>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [x86] BUG: unable to handle kernel paging request at 00740060
Date: Tue, 8 Oct 2013 21:05:23 +0200 [thread overview]
Message-ID: <20131008190523.GW30970@tucnak.zalov.cz> (raw)
In-Reply-To: <20131008185154.GA8258@redhat.com>
On Tue, Oct 08, 2013 at 08:51:54PM +0200, Oleg Nesterov wrote:
> On 10/08, Linus Torvalds wrote:
> >
> > (not yet merged), see:
> >
> > http://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/commit/?id=0c44c2d0f459cd7e275242b72f500137c4fa834d
>
> I do not really understand inline assembly constraints, but I'll ask
> anyway.
>
> +#define __GEN_RMWcc(fullop, var, cc, ...) \
> +do { \
> + asm volatile goto (fullop "; j" cc " %l[cc_label]" \
> + : : "m" (var), ## __VA_ARGS__ \
> ^^^^^^^^^
>
> don't we need
>
> "+m" (var)
>
> here?
You actually can't have output operands with asm goto, only inputs
and clobbers. But the "memory" clobber should be enough here.
If you suspect a compiler bug, can somebody please narrow it down to
a single object file (if I've skimmed the patch right, it is just an
optimization, where object files compiled without and with the patch
should actually coexist fine in the same kernel), ideally to a single
routine if possible and post a preprocessed source + gcc command line
+ version of gcc?
Jakub
next prev parent reply other threads:[~2013-10-08 19:06 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-05 23:44 [x86] BUG: unable to handle kernel paging request at 00740060 Fengguang Wu
2013-10-05 23:47 ` [x86] BUG: unable to handle kernel paging request at 08000060 Fengguang Wu
2013-10-06 7:27 ` Mike Galbraith
2013-10-06 7:36 ` Fengguang Wu
2013-10-07 8:49 ` Peter Zijlstra
2013-10-07 9:17 ` Fengguang Wu
2013-10-07 9:36 ` Peter Zijlstra
2013-10-07 9:46 ` Fengguang Wu
2013-10-07 8:55 ` [x86] BUG: unable to handle kernel paging request at 00740060 Peter Zijlstra
2013-10-07 9:08 ` Peter Zijlstra
2013-10-07 11:32 ` Fengguang Wu
2013-10-07 9:27 ` Fengguang Wu
2013-10-07 18:47 ` Linus Torvalds
2013-10-08 7:51 ` Fengguang Wu
2013-10-08 16:21 ` Linus Torvalds
2013-10-08 17:15 ` [x86] BUG: unable to handle kernel NULL pointer dereference at (null) Fengguang Wu
2013-10-08 17:31 ` Linus Torvalds
2013-10-09 1:09 ` Fengguang Wu
2013-10-09 1:33 ` Linus Torvalds
2013-10-08 18:51 ` [x86] BUG: unable to handle kernel paging request at 00740060 Oleg Nesterov
2013-10-08 19:05 ` Jakub Jelinek [this message]
2013-10-08 19:20 ` Linus Torvalds
2013-10-08 19:34 ` Linus Torvalds
2013-10-08 19:35 ` Oleg Nesterov
2013-10-08 19:49 ` Linus Torvalds
2013-10-09 1:43 ` Mike Galbraith
2013-10-08 19:05 ` Linus Torvalds
2013-10-08 16:46 ` Oleg Nesterov
2013-10-08 14:34 ` Oleg Nesterov
2013-10-09 8:04 ` Fengguang Wu
2013-10-09 12:19 ` Fengguang Wu
2013-10-09 12:21 ` Fengguang Wu
2013-10-09 12:27 ` Peter Zijlstra
2013-10-09 12:52 ` Ingo Molnar
2013-10-09 17:18 ` Ingo Molnar
2013-10-10 2:15 ` Mike Galbraith
2013-10-09 12:56 ` Fengguang Wu
2013-10-09 12:43 ` Oleg Nesterov
2013-10-09 14:07 ` Peter Zijlstra
2013-10-09 14:17 ` Oleg Nesterov
2013-10-09 14:32 ` Ingo Molnar
2013-10-09 14:33 ` Peter Zijlstra
2013-10-09 14:46 ` Peter Zijlstra
2013-10-09 18:16 ` Jakub Jelinek
2013-10-09 18:54 ` Linus Torvalds
2013-10-09 19:02 ` Peter Zijlstra
2013-10-09 19:08 ` Jakub Jelinek
2013-10-10 6:22 ` Ingo Molnar
2013-10-10 6:51 ` Jakub Jelinek
2013-10-10 8:04 ` Jakub Jelinek
2013-10-10 8:24 ` [PATCH] gcc4: Add 'asm goto' miscompilation quirk Ingo Molnar
2013-10-10 8:31 ` Jakub Jelinek
2013-10-10 8:45 ` Ingo Molnar
2013-10-10 8:55 ` [PATCH, -v2] compiler/gcc4: Add quirk for 'asm goto' miscompilation bug Ingo Molnar
2013-10-10 11:56 ` Peter Zijlstra
2013-10-10 12:32 ` Jakub Jelinek
2013-10-10 13:10 ` Peter Zijlstra
2013-10-10 15:04 ` Ingo Molnar
2013-10-10 14:04 ` [PATCH] gcc4: Add 'asm goto' miscompilation quirk Richard Henderson
2013-10-10 14:27 ` Jakub Jelinek
2013-10-10 15:12 ` [PATCH, -v3] compiler/gcc4: Add quirk for 'asm goto' miscompilation bug Ingo Molnar
2013-10-10 16:15 ` Richard Henderson
2013-10-10 16:49 ` Ingo Molnar
2013-10-11 4:35 ` Fengguang Wu
2013-10-11 5:46 ` Ingo Molnar
2013-10-11 6:51 ` Fengguang Wu
2013-10-11 9:30 ` Fengguang Wu
2013-10-12 17:03 ` Ingo Molnar
2013-10-10 8:34 ` [PATCH] gcc4: Add 'asm goto' miscompilation quirk Ingo Molnar
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