Messages in this thread | | | Date | Mon, 26 Oct 2009 09:37:06 -0700 | From | Andrew Morton <> | Subject | Re: Unnecessary overhead with stack protector. |
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On Mon, 26 Oct 2009 12:30:04 -0400 Chuck Ebbert <cebbert@redhat.com> wrote:
> On Wed, 21 Oct 2009 18:26:36 -0700 > Andrew Morton <akpm@linux-foundation.org> wrote: > > > On Thu, 15 Oct 2009 14:35:41 -0400 Dave Jones <davej@redhat.com> wrote: > > > > > 113c5413cf9051cc50b88befdc42e3402bb92115 introduced a change that > > > made CC_STACKPROTECTOR_ALL not-selectable if someone enables CC_STACKPROTECTOR. > > > > > > We've noticed in Fedora that this has introduced noticable overhead on > > > some functions, including those which don't even have any on-stack variables. > > > > > > According to the gcc manpage, -fstack-protector will protect functions with > > > as little as 8 bytes of stack usage. So we're introducing a huge amount > > > of overhead, to close a small amount of vulnerability (the >0 && <8 case). > > > > > > The overhead as it stands right now means this whole option is unusable for > > > a distro kernel without reverting the above commit. > > > > > > > This looks like a fairly serious problem to me, but I'm confused by the > > commit ID. February 2008 - is this correct? > > > > That date is pure fiction AFAICT. And the Mercurial kernel repo says May 2008... > Is there some way to get the date a change was merged into the official tree as > opposed to the date it was created in some other tree?
oh, so someone _did_ read my email!
git show --pretty=fuller 113c5413cf9051cc50b88befdc42e3402bb92115
commit 113c5413cf9051cc50b88befdc42e3402bb92115 Author: Ingo Molnar <mingo@elte.hu> AuthorDate: Thu Feb 14 10:36:03 2008 +0100 Commit: Thomas Gleixner <tglx@linutronix.de> CommitDate: Mon May 26 16:15:32 2008 +0200
I think the CommitDate is when it hit mainline.
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