From: Leonid Yegoshin Date: Fri, 24 May 2013 22:55:18 +0000 (-0700) Subject: mm compaction: fix of improper cache flush in migration code X-Git-Tag: v3.2.46~32 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7fa32acca588177bbc49dc2b4c6fa469c4aa5bd5;p=pandora-kernel.git mm compaction: fix of improper cache flush in migration code commit c2cc499c5bcf9040a738f49e8051b42078205748 upstream. Page 'new' during MIGRATION can't be flushed with flush_cache_page(). Using flush_cache_page(vma, addr, pfn) is justified only if the page is already placed in process page table, and that is done right after flush_cache_page(). But without it the arch function has no knowledge of process PTE and does nothing. Besides that, flush_cache_page() flushes an application cache page, but the kernel has a different page virtual address and dirtied it. Replace it with flush_dcache_page(new) which is the proper usage. The old page is flushed in try_to_unmap_one() before migration. This bug takes place in Sead3 board with M14Kc MIPS CPU without cache aliasing (but Harvard arch - separate I and D cache) in tight memory environment (128MB) each 1-3days on SOAK test. It fails in cc1 during kernel build (SIGILL, SIGBUS, SIGSEG) if CONFIG_COMPACTION is switched ON. Signed-off-by: Leonid Yegoshin Cc: Leonid Yegoshin Acked-by: Rik van Riel Cc: Michal Hocko Acked-by: Mel Gorman Cc: Ralf Baechle Cc: Russell King Cc: David Miller Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed