The patch titled Subject: mm compaction: fix of improper cache flush in migration code has been added to the -mm tree. Its filename is mm-compaction-fix-of-improper-cache-flush-in-migration-code.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Leonid Yegoshin <Leonid.Yegoshin@xxxxxxxxxx> Subject: mm compaction: fix of improper cache flush in migration code 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 <Leonid.Yegoshin@xxxxxxxxxx> Cc: Leonid Yegoshin <yegoshin@xxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxx> Cc: Mel Gorman <mel@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/migrate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN mm/migrate.c~mm-compaction-fix-of-improper-cache-flush-in-migration-code mm/migrate.c --- a/mm/migrate.c~mm-compaction-fix-of-improper-cache-flush-in-migration-code +++ a/mm/migrate.c @@ -165,7 +165,7 @@ static int remove_migration_pte(struct p pte = arch_make_huge_pte(pte, vma, new, 0); } #endif - flush_cache_page(vma, addr, pte_pfn(pte)); + flush_dcache_page(new); set_pte_at(mm, addr, ptep, pte); if (PageHuge(new)) { _ Patches currently in -mm which might be from Leonid.Yegoshin@xxxxxxxxxx are linux-next.patch mm-compaction-fix-of-improper-cache-flush-in-migration-code.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html