Messages in this thread | | | Date | Mon, 28 Sep 2009 06:11:08 +0200 | From | Andi Kleen <> | Subject | Re: [RFC][PATCH] HWPOISON: remove the unsafe __set_page_locked() |
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On Mon, Sep 28, 2009 at 04:57:41AM +0200, Nick Piggin wrote: > On Mon, Sep 28, 2009 at 03:19:43AM +0200, Andi Kleen wrote: > > > There is no real rush AFAIKS to fix this one single pagecache site > > > while we have problems with slab allocators and all other unaudited > > > places that nonatomically modify page flags with an elevated > > > > hwpoison ignores slab pages. > > "ignores" them *after* it has already written to page flags? > By that time it's too late.
Yes, currently the page lock comes first. The only exception is for page count == 0 pages. I suppose we could move the slab check up, but then it only helps when slab is set.
So if you make slab use refcount == 0 pages that would help.
> Well it's fundamentally badly buggy, rare or not. We could avoid
Let's put it like this -- any access to the poisoned cache lines in that page will trigger a panic anyways.
-Andi
-- ak@linux.intel.com -- Speaking for myself only.
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