From: Shaokun Zhang <zhangshaokun@xxxxxxxxxxxxx> This patch has been added to the 3.18 stable tree. If you have any objections, please let us know. =============== [ Upstream commit 20c27a4270c775d7ed661491af8ac03264d60fc6 ] __sync_icache_dcache unconditionally skips the cache maintenance for anonymous pages, under the assumption that flushing is only required in the presence of D-side aliases [see 7249b79f6b4cc ("arm64: Do not flush the D-cache for anonymous pages")]. Unfortunately, this breaks migration of anonymous pages holding self-modifying code, where userspace cannot be reasonably expected to reissue maintenance instructions in response to a migration. This patch fixes the problem by removing the broken page_mapping(page) check from the cache syncing code, otherwise we may end up fetching and executing stale instructions from the PoU. Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Will Deacon <will.deacon@xxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx> Signed-off-by: Shaokun Zhang <zhangshaokun@xxxxxxxxxxxxx> Signed-off-by: Will Deacon <will.deacon@xxxxxxx> Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx> --- arch/arm64/mm/flush.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c index b6f14e8..bfb8eb16 100644 --- a/arch/arm64/mm/flush.c +++ b/arch/arm64/mm/flush.c @@ -74,10 +74,6 @@ void __sync_icache_dcache(pte_t pte, unsigned long addr) { struct page *page = pte_page(pte); - /* no flushing needed for anonymous pages */ - if (!page_mapping(page)) - return; - if (!test_and_set_bit(PG_dcache_clean, &page->flags)) { __flush_dcache_area(page_address(page), PAGE_SIZE << compound_order(page)); -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html