On Mon, 2012-07-02 at 20:46 -0300, Herton Ronaldo Krzesinski wrote: > On Sun, Jul 01, 2012 at 06:20:13PM +0100, Ben Hutchings wrote: > > 3.2-stable review patch. If anyone has any objections, please let me know. > > > > ------------------ > > > > From: Pravin B Shelar <[email protected]> > > > > commit abca7c4965845924f65d40e0aa1092bdd895e314 upstream. > > > > On arches that do not support this_cpu_cmpxchg_double() slab_lock is used > > to do atomic cmpxchg() on double word which contains page->_count. The > > page count can be changed from get_page() or put_page() without taking > > slab_lock. That corrupts page counter. > > > > Fix it by moving page->_count out of cmpxchg_double data. So that slub > > does no change it while updating slub meta-data in struct page. > > Hi, > > I got a frozen machine on boot with 3.2.22 proposed patches, bisect > pointed out to this commit (and reverting only this commit on top of > 3.2.22 patches confirmed it). So far I was able to reproduce always. [...]
Sorry, I should remember to test with SLUB whenever there's a patch that touches it! I'll drop this for now, given Pravin's feedback. Please let me know when this is completely fixed in mainline and ready to be cherry-picked/backported. Ben. -- Ben Hutchings When in doubt, use brute force. - Ken Thompson
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