From: Peter Zijlstra <peterz@infradead.org>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: kernel test robot <lkp@intel.com>,
Steven Rostedt <rostedt@goodmis.org>,
LKML <linux-kernel@vger.kernel.org>,
x86@kernel.org, lkp@lists.01.org, keescook@chromium.org,
hjl.tools@gmail.com
Subject: Re: [sched] c3a340f7e7: invalid_opcode:#[##]
Date: Tue, 30 Jun 2020 16:35:04 +0200 [thread overview]
Message-ID: <20200630143504.GI117543@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200630140231.GW4817@hirez.programming.kicks-ass.net>
On Tue, Jun 30, 2020 at 04:02:31PM +0200, Peter Zijlstra wrote:
> On Tue, Jun 30, 2020 at 03:55:05PM +0200, Rasmus Villemoes wrote:
>
> > > Consistently so with GCC-4.9. Any other GCC I tried does the sane thing.
> >
> > Does that include gcc 4.8, or is it only "anything newer than 4.9"?
>
> It includes 4.8 :-)
>
> > so the section it was put in has an alignment of 64. The generated
> > assembly is indeed
> >
> > .globl fair_sched_class
> > .section __fair_sched_class,"a",@progbits
> > .align 64
> >
> > /me goes brew coffee
>
> Right.. so I now have the below patch, and with that I get:
>
> 62931: c1e62c20 0 NOTYPE GLOBAL DEFAULT 2 __begin_sched_classes
> 65736: c1e62e40 128 OBJECT GLOBAL DEFAULT 2 stop_sched_class
> 71813: c1e62cc0 128 OBJECT GLOBAL DEFAULT 2 fair_sched_class
> 78689: c1e62c40 128 OBJECT GLOBAL DEFAULT 2 idle_sched_class
> 78953: c1e62ec0 0 NOTYPE GLOBAL DEFAULT 2 __end_sched_classes
> 79090: c1e62d40 128 OBJECT GLOBAL DEFAULT 2 rt_sched_class
> 79431: c1e62dc0 128 OBJECT GLOBAL DEFAULT 2 dl_sched_class
>
>
> Which has me stumped on __begin_sched_classes being on a 32byte edge
> (and crashes differently due to that).
OK, when I look at defconfig-build/arch/x86/kernel/vmlinux.lds I get:
. = ALIGN(32); *(__dummy_sched_class) __begin_sched_classes = .;
So I'm thinking the GCC_VERSION thing works for sched.h but not for
arch//x86/kernel/vmlinux.lds.S, lovely. Let me try and figure out why.
next prev parent reply other threads:[~2020-06-30 14:35 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-29 0:31 [sched] c3a340f7e7: invalid_opcode:#[##] kernel test robot
2020-06-30 12:46 ` Peter Zijlstra
2020-06-30 13:55 ` Rasmus Villemoes
2020-06-30 14:02 ` Peter Zijlstra
2020-06-30 14:11 ` Peter Zijlstra
2020-06-30 14:35 ` Peter Zijlstra [this message]
2020-06-30 14:49 ` Peter Zijlstra
2020-07-09 8:45 ` [tip: sched/core] sched, vmlinux.lds: Increase STRUCT_ALIGNMENT to 64 bytes for GCC-4.9 tip-bot2 for Peter Zijlstra
2020-10-20 23:39 ` [sched] c3a340f7e7: invalid_opcode:#[##] Florian Fainelli
2020-10-21 8:00 ` GCC section alignment, and GCC-4.9 being a weird one Peter Zijlstra
2020-10-21 13:18 ` Jakub Jelinek
2020-10-21 13:44 ` Peter Zijlstra
2020-10-21 17:42 ` Nick Desaulniers
2020-10-21 17:54 ` Miguel Ojeda
2020-10-21 18:35 ` Joe Perches
2020-10-21 19:27 ` Miguel Ojeda
2020-10-22 7:38 ` Peter Zijlstra
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