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From:   Sumit Garg <sumit.garg@linaro.org>
Date:   Wed, 14 Jul 2021 10:33:33 +0530
Message-ID: <CAFA6WYOMMGxoVg-WezjwAUhPjsu-dfKi=1DY-RDJjyiEA9P7QA@mail.gmail.com>
Subject: Re: [PATCH v3] kdb: Get rid of custom debug heap allocator
To:     Doug Anderson <dianders@chromium.org>
Cc:     Daniel Thompson <daniel.thompson@linaro.org>,
        kgdb-bugreport@lists.sourceforge.net,
        Jason Wessel <jason.wessel@windriver.com>,
        LKML <linux-kernel@vger.kernel.org>
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On Tue, 13 Jul 2021 at 20:42, Doug Anderson <dianders@chromium.org> wrote:
>
> Hi,
>
> On Tue, Jul 13, 2021 at 8:10 AM Daniel Thompson
> <daniel.thompson@linaro.org> wrote:
> >
> > On Tue, Jul 13, 2021 at 06:45:52AM -0700, Doug Anderson wrote:
> > > Hi,
> > >
> > > On Tue, Jul 13, 2021 at 4:24 AM Sumit Garg <sumit.garg@linaro.org> wrote:
> > > >
> > > > > >  int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab)
> > > > > >  {
> > > > > >         int ret = 0;
> > > > > >         unsigned long symbolsize = 0;
> > > > > >         unsigned long offset = 0;
> > > > > > -#define knt1_size 128          /* must be >= kallsyms table size */
> > > > > > -       char *knt1 = NULL;
> > > > > > +       static char namebuf[KSYM_NAME_LEN];
> > > > >
> > > > > I guess this also ends up fixing a bug too, right? My greps show that
> > > > > "KSYM_NAME_LEN" is 512
> > > >
> > > > I can see "KSYM_NAME_LEN" defined as 128 here [1]. Are you looking at
> > > > any other header file?
> > > >
> > > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/kallsyms.h#n18
> > >
> > > Ah ha, it's recent! See commit f2f6175186f4 ("kallsyms: increase
> > > maximum kernel symbol length to 512")
> >
> > Ineed. So recent that I think it hasn't been merged to mainline yet!
> >
> > This patch is part of the rust patch set. IIUC it is in linux-next for
> > wider testing but I'd be surprised if it gets merged to mainline anytime
> > soon (and even more amazed if it is merged without being rebased and
> > given a new hash value ;-) ).
>
> Ah, good point. Yeah, I should have mentioned that I was looking at
> linuxnext. I guess maybe the right compromise is just to mention that
> we'll be more robust in case that other #define changes. ;-)
>

Okay, I will update the commit description accordingly.

-Sumit

> -Doug