Re: [PATCH 3/3] kasan: stackdepot: move filter_irq_stacks() to stackdepot.c

From: Greentime Hu <green.hu@gmail.com>
To: Alexander Potapenko <glider@google.com>
Cc: Nick Hu <nickhu@andestech.com>,
	Vincent Chen <deanbo422@gmail.com>,
	 Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	 Arnd Bergmann <arnd@arndb.de>,
	Linux Memory Management List <linux-mm@kvack.org>,
	kbuild-all@lists.01.org
Subject: Re: [PATCH 3/3] kasan: stackdepot: move filter_irq_stacks() to stackdepot.c
Date: Thu, 27 Feb 2020 11:16:17 +0800	[thread overview]
Message-ID: <CAEbi=3dg2qYC=wModQmXcTp_=BBKKBuuwG2WxpW43n2760s-TA@mail.gmail.com> (raw)
In-Reply-To: <CAG_fn=X7mUyJxLBMohkud6DEwyf6gvU7j_eXW6kc_qYUdURo=Q@mail.gmail.com>

Alexander Potapenko <glider@google.com> 於 2020年2月26日 週三 下午5:53寫道：
>
> Hi Andes maintainers,
>
> On Tue, Feb 25, 2020 at 9:26 PM kbuild test robot <lkp@intel.com> wrote:
> >
> > Hi,
> >
> > I love your patch! Yet something to improve:
> >
> > [auto build test ERROR on linus/master]
> > [also build test ERROR on v5.6-rc3 next-20200225]
> > [if your patch is applied to the wrong git tree, please drop us a note to help
> > improve the system. BTW, we also suggest to use '--base' option to specify the
> > base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
> >
> > url:    https://github.com/0day-ci/linux/commits/glider-google-com/stackdepot-check-depot_index-before-accessing-the-stack-slab/20200222-065605
> > base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 0c0ddd6ae47c9238c18f475bcca675ca74c9dc31
> > config: nds32-randconfig-a001-20200225 (attached as .config)
> > compiler: nds32le-linux-gcc (GCC) 9.2.0
> > reproduce:
> >         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> >         chmod +x ~/bin/make.cross
> >         # save the attached .config to linux build tree
> >         GCC_VERSION=9.2.0 make.cross ARCH=nds32
> >
> > If you fix the issue, kindly add following tag
> > Reported-by: kbuild test robot <lkp@intel.com>
> >
> > All errors (new ones prefixed by >>):
> >
> >    nds32le-linux-ld: lib/stackdepot.o: in function `filter_irq_stacks':
> > >> stackdepot.c:(.text+0xc6): undefined reference to `__softirqentry_text_start'
> > >> nds32le-linux-ld: stackdepot.c:(.text+0xca): undefined reference to `__softirqentry_text_start'
> > >> nds32le-linux-ld: stackdepot.c:(.text+0xce): undefined reference to `__softirqentry_text_end'
> >    nds32le-linux-ld: stackdepot.c:(.text+0xd2): undefined reference to `__softirqentry_text_end'
>
> Can you please help me with this?
> I couldn't find out where this section needs to be declared, and I
> don't really know whether nds32 is supposed to have softirqs or not.
> Maybe filter_irq_stacks() should be no-op on nds32?

Hi Alexander,

I've disccussed this with Nick.
There might be 2 solutions, but we are not sure which one is better or
maybe there are another better solutions.
Since nds32 doesn't support KASAN, we might not need to use this section.

Solution 1.
  We may just add the dependency in STACKDEPOT depend on KASAN

Solution 2.
  Just add SOFTIRQENTRY_TEXT this section to nds32's linker script

What do you think? :)