linux-kernel - Re: [PATCHSET x86/core/percpu] implement dynamic percpu allocator

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <200902192244.15055.rusty@rustcorp.com.au>
Date:	Thu, 19 Feb 2009 22:44:14 +1030
From:	Rusty Russell <rusty@...tcorp.com.au>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Tejun Heo <tj@...nel.org>, tglx@...utronix.de, x86@...nel.org,
	linux-kernel@...r.kernel.org, hpa@...or.com, jeremy@...p.org,
	cpw@....com
Subject: Re: [PATCHSET x86/core/percpu] implement dynamic percpu allocator

On Thursday 19 February 2009 21:36:31 Ingo Molnar wrote:
> 
> * Rusty Russell <rusty@...tcorp.com.au> wrote:
> 
> > On Thursday 19 February 2009 00:13:31 Ingo Molnar wrote:
> > > 
> > > * Tejun Heo <tj@...nel.org> wrote:
> > > 
> > > >   0001-vmalloc-call-flush_cache_vunmap-from-unmap_kernel.patch
> > > >   0002-module-fix-out-of-range-memory-access.patch
> > > 
> > > Hm, these two seem to be .29 material too, agreed?
> > > 
> > > Rusty, if the fixes are fine with you i can put those two 
> > > commits into tip/core/urgent straight away, the full string of 
> > > 10 commits into tip/core/percpu and thus we'd avoid duplicate 
> > > (or even conflicting) commits.
> > 
> > No, the second one is not .29 material; it's a nice, but 
> > theoretical, fix.
> 
> Can it never trigger?

Actually, checked again.  It's not even necessary AFAICT (tho a comment
would be nice):

	for (i = 0; i < pcpu_num_used; ptr += block_size(pcpu_size[i]), i++) {
		/* Extra for alignment requirement. */
		extra = ALIGN((unsigned long)ptr, align) - (unsigned long)ptr;
		BUG_ON(i == 0 && extra != 0);

		if (pcpu_size[i] < 0 || pcpu_size[i] < extra + size)
			continue;

		/* Transfer extra to previous block. */
		if (pcpu_size[i-1] < 0)
			pcpu_size[i-1] -= extra;
		else
			pcpu_size[i-1] += extra;

pcpu_size[0] is *always* negative: it's marked allocated at initialization
(it's the static per-cpu allocations).

Sorry I didn't examine more closely,
Rusty.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/