Re: [PATCH] Fix allocation sizes of knfsd raparm hash

From: J. Bruce Fields
Date: Mon Aug 18 2008 - 10:59:41 EST


On Sat, Aug 16, 2008 at 10:45:56AM +0200, Takashi Iwai wrote:
> At Fri, 15 Aug 2008 15:02:21 -0400,
> J. Bruce Fields wrote:
> >
> > On Fri, Aug 15, 2008 at 03:34:39PM +0200, Takashi Iwai wrote:
> > > The raparm was allocated in a wrong size in the commit
> > >
> > > ca80290ebda9009aedc4bd93ede5d397cb1853dc
> > > nfsd: permit unauthenticated stat of export root
> > >
> > > and thus it resulted in memory corruption, eventually Oopsing.
> > > This patch fixes the allocation size.
> >
> > Whoops, my fault, now fixed; thanks!
> >
> > (Out of curiosity--how did you find this?)
>
> Actually I hit the related Oops with the latest linux-next tree.
> Since this bug appears first on that tree and didn't occur on the
> previous tree, it was apparently a regression. So, I looked through
> changes over knfsd since the previous tree, found a suspicious one,
> and tried to fix.
>
> The linux-next tree is pretty helpful to catch a regression if one
> eats own dog foods everyday.

OK, now I see my problem: my test systems deliver the rest of their
results by email, but if I want to check the logs for oops messages I
still need to remember to log in and look after each test run. So I got
lazy and missed the slab errors on nfsd shutdown.

I wonder what the easiest way would be to automate collection of oops
messages from the logs? I suppose I should look at what the code that
submits to kerneloops.org does.

--b.

>
> BTW, I've been building linux-next SUSE kernel packages at every
> linux-next release. The packages are found in the following URL:
>
> http://ftp.suse.com/pub/people/tiwai/kernel-next/
>
> If anyone has a SUSE system and would like to try linux-next kernel,
> just installs the package in addition. It won't conflict with
> existing standard kernel packages.
>
>
> thanks,
>
> Takashi
>
> >
> > --b.
> >
> > >
> > > Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
> > >
> > > ---
> > > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> > > index bfa5453..30d606f 100644
> > > --- a/fs/nfsd/vfs.c
> > > +++ b/fs/nfsd/vfs.c
> > > @@ -2093,7 +2093,7 @@ nfsd_racache_init(int cache_size)
> > >
> > > raparm = &raparm_hash[i].pb_head;
> > > for (j = 0; j < nperbucket; j++) {
> > > - *raparm = kzalloc(sizeof(*raparm), GFP_KERNEL);
> > > + *raparm = kzalloc(sizeof(**raparm), GFP_KERNEL);
> > > if (!*raparm)
> > > goto out_nomem;
> > > raparm = &(*raparm)->p_next;
> >
--
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