From: Paul Mackerras <paulus@samba•org>
To: Ingo Molnar <mingo@elte•hu>
Cc: Sam Ravnborg <sam@ravnborg•org>, Yinghai Lu <yinghai@kernel•org>,
David Howells <dhowells@redhat•com>,
Kamalesh Babulal <kamalesh@linux•vnet.ibm.com>,
Andrew Morton <akpm@linux-foundation•org>,
Stephen Rothwell <sfr@canb•auug.org.au>,
linux-next@vger•kernel.org, LKML <linux-kernel@vger•kernel.org>,
mel@csn•ul.ie
Subject: Re: [PATCH] kbuild, sparseirq: work around GCC bug with __weak aliases
Date: Sat, 27 Dec 2008 15:09:44 +1100 [thread overview]
Message-ID: <18773.43656.189438.155690@cargo.ozlabs.ibm.com> (raw)
In-Reply-To: <20081226134218.GA1054@elte.hu>
Ingo Molnar writes:
> * Ingo Molnar <mingo@elte•hu> wrote:
>
> > > I recall David Howells had a similar issue with the bootparamter patch
> > > set. The workaround he used was to add a barrier(); call in the weak
> > > function to avoid the inline.
> >
> > could we add some extra attribute to __weak that would have a similar
> > effect? Something like __attribute__((noinline)), or something silly
> > like __attribute__((deprecated)) - just to keep gcc from screwing up
> > __weak functions? Perhaps adding a section attribute would have a
> > similar effect? (putting weak definitions into an extra section is
> > probably helpful anyway)
>
> I've applied the patch below to tip/irq/sparseirq - could someone with an
> affected GCC version please check whether this solves the crash?
I recall from discussions earlier that noinline doesn't fix the
problem, and I just tested a similar case and verified that adding
noinline doesn't stop some versions of gcc from inlining them. The
empty weak functions in kernel/perf_counter.c were getting inlined by
the cross-gcc (gcc 4.1.1) I use for compiling powerpc kernels on my
laptop, and adding noinline doesn't help there.
Paul.
next prev parent reply other threads:[~2008-12-27 4:11 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-16 11:37 linux-next: Tree for December 16 Stephen Rothwell
2008-12-16 23:26 ` Andrew Morton
2008-12-17 6:59 ` linux-next: mtd tree build failures (Was: Re: linux-next: Tree for December 16) Stephen Rothwell
2008-12-17 9:32 ` Artem Bityutskiy
2008-12-17 9:57 ` Stephen Rothwell
2008-12-17 7:07 ` linux-next: Tree for December 16 Artem Bityutskiy
2008-12-17 7:08 ` next-20081216 - powerpc link error 'dynreloc miscount' Kamalesh Babulal
2008-12-17 7:28 ` Sam Ravnborg
2008-12-17 7:30 ` Stephen Rothwell
2008-12-19 10:54 ` [BUG] next-20081216 - WARNING: at kernel/smp.c:333 smp_call_function_mask Kamalesh Babulal
2008-12-19 11:51 ` Yinghai Lu
2008-12-19 13:46 ` Kamalesh Babulal
2008-12-19 21:02 ` Yinghai Lu
2008-12-23 13:21 ` Kamalesh Babulal
2008-12-23 21:09 ` Yinghai Lu
2008-12-24 16:34 ` Kamalesh Babulal
2008-12-24 20:34 ` Yinghai Lu
2008-12-26 9:12 ` Kamalesh Babulal
2008-12-26 10:05 ` Yinghai Lu
2008-12-26 10:27 ` Sam Ravnborg
2008-12-26 13:33 ` Ingo Molnar
2008-12-26 13:42 ` [PATCH] kbuild, sparseirq: work around GCC bug with __weak aliases Ingo Molnar
2008-12-27 4:09 ` Paul Mackerras [this message]
2008-12-27 10:59 ` Ingo Molnar
2008-12-28 23:27 ` Paul Mackerras
2008-12-26 15:28 ` [BUG] next-20081216 - WARNING: at kernel/smp.c:333 smp_call_function_mask Kamalesh Babulal
2008-12-26 15:33 ` Ingo Molnar
2008-12-26 17:04 ` Kamalesh Babulal
2008-12-26 18:17 ` Ingo Molnar
2008-12-27 7:11 ` Kamalesh Babulal
2008-12-27 7:14 ` Yinghai Lu
2008-12-27 7:39 ` Yinghai Lu
2008-12-27 8:37 ` Ingo Molnar
2008-12-27 8:39 ` Ingo Molnar
2008-12-27 11:21 ` Kamalesh Babulal
2008-12-27 11:24 ` Ingo Molnar
2008-12-27 11:57 ` Kamalesh Babulal
2008-12-27 12:26 ` Ingo Molnar
2008-12-27 15:29 ` Kamalesh Babulal
2008-12-27 21:10 ` Yinghai Lu
2008-12-28 12:55 ` Ingo Molnar
2008-12-28 16:11 ` Kamalesh Babulal
2008-12-28 23:09 ` Yinghai Lu
2008-12-27 5:05 ` [PATCH] perf_counter: more barrier in blank weak function Yinghai Lu
2008-12-27 5:06 ` [PATCH] kgdb: " Yinghai Lu
2008-12-27 8:17 ` Ingo Molnar
2008-12-27 8:34 ` Andrew Morton
2008-12-27 6:07 ` [PATCH] perf_counter: " KOSAKI Motohiro
2008-12-27 9:46 ` [BUG] next-20081216 - WARNING: at kernel/smp.c:333 smp_call_function_mask David Howells
2008-12-27 9:50 ` Ingo Molnar
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