linux-kernel - Re: linux-next: build failure after merge of the akpm-current tree

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150724230902.GQ3717@linux.vnet.ibm.com>
Date:	Fri, 24 Jul 2015 16:09:02 -0700
From:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	Davidlohr Bueso <dave@...olabs.net>
Cc:	Stephen Rothwell <sfr@...b.auug.org.au>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-next@...r.kernel.org, linux-kernel@...r.kernel.org,
	josh@...htriplett.org
Subject: Re: linux-next: build failure after merge of the akpm-current tree

On Fri, Jul 24, 2015 at 01:16:05PM -0700, Davidlohr Bueso wrote:
> On Fri, 2015-07-24 at 15:33 +1000, Stephen Rothwell wrote:
> > Hi Andrew,
> > 
> > After merging the akpm-current tree, today's linux-next build (powerpc
> > allnoconfig) failed like this:
> > 
> > mm/built-in.o: In function `shrink_slab.part.73.constprop.83':
> > vmscan.c:(.text+0xf760): undefined reference to `__srcu_read_lock'
> > vmscan.c:(.text+0xf924): undefined reference to `__srcu_read_unlock'
> > mm/built-in.o: In function `unregister_shrinker':
> > (.text+0xfa60): undefined reference to `synchronize_srcu'
> > mm/built-in.o:(.data+0x1e8): undefined reference to `process_srcu'
> > 
> > Caused by commit
> > 
> >   dab937da82f9 ("mm: srcu-ify shrinkers")
> > 
> > I have reverted that commit for today.
> 
> Adding paulmck.
> 
> I'm not entirely sure what is the fix here. Paul G also reported it
> failing for arm. I was able to reproduce with powerpc, and the following
> fixes the issue, but I doubt it is the correct way to address this. The
> idea was based on how we do it for x86.
> 
> Also, having SRCU in mm is, lets say, more than convenient, beyond
> MMU_NOTIFIERS which explicitly selects SRCU.
> 
> Paul?

SRCU was made optional as part of the kernel tinification project,
so adding Josh on CC.  The hope would be that the feature needing SRCU
could add the "select" rather than having major architectures doing so.

I guess if SRCU is needed everywhere, it is needed everywhere, but...

							Thanx, Paul

> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 5ef2711..774207e 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -124,6 +124,7 @@ config PPC
>         select GENERIC_IRQ_SHOW
>         select GENERIC_IRQ_SHOW_LEVEL
>         select IRQ_FORCED_THREADING
> +       select SRCU
>         select HAVE_RCU_TABLE_FREE if SMP
>         select HAVE_SYSCALL_TRACEPOINTS
>         select HAVE_BPF_JIT
> 
> Thanks,
> Davidlohr
> 

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/