Who broke cb8f488c33 patch? (was Re: [PATCH 1/1] USBHID: correctstart/stop cycle)

From: Jiri Kosina
Date: Tue Nov 11 2008 - 19:45:51 EST


On Wed, 12 Nov 2008, Denys Vlasenko wrote:

> > > > I fully bisected it, and the final "buggy" patch seems to have been
> > > > Denys Vlasenko's patch: cb8f488c33539f096580e202f5438a809195008f (see
> > > > http://github.com/jonsmirl/digispeaker/commit/cb8f488c33539f096580e202f5438a809195008f)
> > > > Denys: Any reason you removed "!prev" in front of "expand_stack"?
> > > Looks like I erroneously thought it can't be NULL,
> > > or that expand_upwards() is ok with getting NULL vma parameter.
> > > I looked again and neither is true.
> > > Sorry, looks like I indeed broke this.
> > Hmm, so ... ? Seems like this didn't get fixed in Linus' tree yet?
> I found my original email in "sent" folder. The patch in that mail does
> NOT remove !prev. That change had beed added by someone else. See
> attached file with original email.
> Ok, I think we are not much interested in who did it,

Hmm, I in fact think we would like to know who removed the check and
folded it into your original patch. I have added all the Signoffs and CCs
to the recepient list.

Andrew usually puts

[someone@xxxxxxxxxxxxx: added this and that to the patch]

marker into the changelog, but it's not the case here.

Having your name in Signed-off-by field of something you are not aware of
should make you feel at least a little bit nervous IMHO.

> let's fix it for good.
> Signed-off-by: Denys Vlasenko <vda.linux@xxxxxxxxxxxxxx>
> --- linux-2.6.28-rc4/mm/mmap.c Mon Nov 10 01:36:15 2008
> +++ linux-2.6.28-rc4.fix/mm/mmap.c Wed Nov 12 01:21:39 2008
> @@ -1704,7 +1704,7 @@
> vma = find_vma_prev(mm, addr, &prev);
> if (vma && (vma->vm_start <= addr))
> return vma;
> - if (expand_stack(prev, addr))
> + if (!prev || expand_stack(prev, addr))
> return NULL;
> if (prev->vm_flags & VM_LOCKED) {
> if (mlock_vma_pages_range(prev, addr, prev->vm_end) < 0)

Thanks,

--
Jiri Kosina
SUSE Labs
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