On Sat, Feb 16, 2013 at 10:26:30AM -0800, Linus Torvalds wrote: > On Fri, Feb 15, 2013 at 3:44 AM, Ingo Molnar <mi...@kernel.org> wrote: > >> > >> c060f943d092 may be related as you config does not have > >> CONFIG_SPARSEMEM defined. > > > > Right, that's the commit causing the x86 regression: > > > > c060f943d0929f3e429c5d9522290584f6281d6e is the first bad commit > > commit c060f943d0929f3e429c5d9522290584f6281d6e > > Date: Fri Jan 11 14:31:51 2013 -0800 > > > > mm: use aligned zone start for pfn_to_bitidx calculation > > Ok, looking more at this, I don't really want to revert it, and I have > an idea of what is wrong. > > When we allocate the zone use bitmap, we do not take the > zone_start_pfn into account. So I *think* that what happens is that > "pfn_to_bitidx()" simply overruns the allocation for unaligned zonesm > and the spinlock just happens to be right after (or the overrun causes > some other memory corruption that then indirectly causes the spinlock > corruption). >
More likely the latter. I'd expect the usemap to be adjacent to the zone->wait_table because of when they are allocated by the bootmem allocator. This would break wait_on_page_[locked|writeback] at the very least. If page_waitqueue() returned a corrupt pointer from the wait table then it would lead to further corruption elsewhere each time wait_on_page_foo was called. > So I'm wondering if the fix is simply something like the attached > patch. It takes the zone_start_pfn into account when allocating the > zone bitmap. > > Laura? Mel? > Looks correct to me and should cc sta...@vger.kernel.org Acked-by: Mel Gorman <mgor...@suse.de> -- Mel Gorman SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
