Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760690AbaLLGdY (ORCPT ); Fri, 12 Dec 2014 01:33:24 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:51972 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759332AbaLLGQ6 (ORCPT ); Fri, 12 Dec 2014 01:16:58 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Will Deacon" , "Linus Torvalds" Date: Fri, 12 Dec 2014 06:14:25 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 091/164] zap_pte_range: update addr when forcing flush after TLB batching faiure In-Reply-To: X-SA-Exim-Connect-IP: 2001:470:1f08:1539:c97:8151:cc89:c28d X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.65-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Will Deacon commit ce9ec37bddb633404a0c23e1acb181a264e7f7f2 upstream. When unmapping a range of pages in zap_pte_range, the page being unmapped is added to an mmu_gather_batch structure for asynchronous freeing. If we run out of space in the batch structure before the range has been completely unmapped, then we break out of the loop, force a TLB flush and free the pages that we have batched so far. If there are further pages to unmap, then we resume the loop where we left off. Unfortunately, we forget to update addr when we break out of the loop, which causes us to truncate the range being invalidated as the end address is exclusive. When we re-enter the loop at the same address, the page has already been freed and the pte_present test will fail, meaning that we do not reconsider the address for invalidation. This patch fixes the problem by incrementing addr by the PAGE_SIZE before breaking out of the loop on batch failure. Signed-off-by: Will Deacon Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: adjust context; add braces] Signed-off-by: Ben Hutchings --- --- a/mm/memory.c +++ b/mm/memory.c @@ -1178,8 +1178,10 @@ again: if (unlikely(page_mapcount(page) < 0)) print_bad_pte(vma, addr, ptent, page); force_flush = !__tlb_remove_page(tlb, page); - if (force_flush) + if (force_flush) { + addr += PAGE_SIZE; break; + } continue; } /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/