Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761658AbaGRNTc (ORCPT ); Fri, 18 Jul 2014 09:19:32 -0400 Received: from bband-dyn38.178-41-141.t-com.sk ([178.41.141.38]:18006 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1761042AbaGRNT2 (ORCPT ); Fri, 18 Jul 2014 09:19:28 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Hugh Dickins , KOSAKI Motohiro , Minchan Kim , Andrew Morton , Linus Torvalds , Jiri Slaby Subject: [PATCH 3.12 126/170] mm: fix crashes from mbind() merging vmas Date: Fri, 18 Jul 2014 14:12:11 +0200 Message-Id: <4c4071938fab9a592014426ede8d0bb0f68e5392.1405685481.git.jslaby@suse.cz> X-Mailer: git-send-email 2.0.0 In-Reply-To: <48e8cad86bb1241c08bdaa80db022c25068ff8e0.1405685481.git.jslaby@suse.cz> References: <48e8cad86bb1241c08bdaa80db022c25068ff8e0.1405685481.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hugh Dickins 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit d05f0cdcbe6388723f1900c549b4850360545201 upstream. In v2.6.34 commit 9d8cebd4bcd7 ("mm: fix mbind vma merge problem") introduced vma merging to mbind(), but it should have also changed the convention of passing start vma from queue_pages_range() (formerly check_range()) to new_vma_page(): vma merging may have already freed that structure, resulting in BUG at mm/mempolicy.c:1738 and probably worse crashes. Fixes: 9d8cebd4bcd7 ("mm: fix mbind vma merge problem") Reported-by: Naoya Horiguchi Tested-by: Naoya Horiguchi Signed-off-by: Hugh Dickins Acked-by: Christoph Lameter Cc: KOSAKI Motohiro Cc: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Jiri Slaby --- mm/mempolicy.c | 46 ++++++++++++++++++++-------------------------- 1 file changed, 20 insertions(+), 26 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index a005cc9f6f18..945316989352 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -653,19 +653,18 @@ static unsigned long change_prot_numa(struct vm_area_struct *vma, * @nodes and @flags,) it's isolated and queued to the pagelist which is * passed via @private.) */ -static struct vm_area_struct * +static int queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end, const nodemask_t *nodes, unsigned long flags, void *private) { - int err; - struct vm_area_struct *first, *vma, *prev; - + int err = 0; + struct vm_area_struct *vma, *prev; - first = find_vma(mm, start); - if (!first) - return ERR_PTR(-EFAULT); + vma = find_vma(mm, start); + if (!vma) + return -EFAULT; prev = NULL; - for (vma = first; vma && vma->vm_start < end; vma = vma->vm_next) { + for (; vma && vma->vm_start < end; vma = vma->vm_next) { unsigned long endvma = vma->vm_end; if (endvma > end) @@ -675,9 +674,9 @@ queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end, if (!(flags & MPOL_MF_DISCONTIG_OK)) { if (!vma->vm_next && vma->vm_end < end) - return ERR_PTR(-EFAULT); + return -EFAULT; if (prev && prev->vm_end < vma->vm_start) - return ERR_PTR(-EFAULT); + return -EFAULT; } if (flags & MPOL_MF_LAZY) { @@ -691,15 +690,13 @@ queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end, err = queue_pages_pgd_range(vma, start, endvma, nodes, flags, private); - if (err) { - first = ERR_PTR(err); + if (err) break; - } } next: prev = vma; } - return first; + return err; } /* @@ -1184,16 +1181,17 @@ out: /* * Allocate a new page for page migration based on vma policy. - * Start assuming that page is mapped by vma pointed to by @private. + * Start by assuming the page is mapped by the same vma as contains @start. * Search forward from there, if not. N.B., this assumes that the * list of pages handed to migrate_pages()--which is how we get here-- * is in virtual address order. */ -static struct page *new_vma_page(struct page *page, unsigned long private, int **x) +static struct page *new_page(struct page *page, unsigned long start, int **x) { - struct vm_area_struct *vma = (struct vm_area_struct *)private; + struct vm_area_struct *vma; unsigned long uninitialized_var(address); + vma = find_vma(current->mm, start); while (vma) { address = page_address_in_vma(page, vma); if (address != -EFAULT) @@ -1223,7 +1221,7 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from, return -ENOSYS; } -static struct page *new_vma_page(struct page *page, unsigned long private, int **x) +static struct page *new_page(struct page *page, unsigned long start, int **x) { return NULL; } @@ -1233,7 +1231,6 @@ static long do_mbind(unsigned long start, unsigned long len, unsigned short mode, unsigned short mode_flags, nodemask_t *nmask, unsigned long flags) { - struct vm_area_struct *vma; struct mm_struct *mm = current->mm; struct mempolicy *new; unsigned long end; @@ -1299,11 +1296,9 @@ static long do_mbind(unsigned long start, unsigned long len, if (err) goto mpol_out; - vma = queue_pages_range(mm, start, end, nmask, + err = queue_pages_range(mm, start, end, nmask, flags | MPOL_MF_INVERT, &pagelist); - - err = PTR_ERR(vma); /* maybe ... */ - if (!IS_ERR(vma)) + if (!err) err = mbind_range(mm, start, end, new); if (!err) { @@ -1311,9 +1306,8 @@ static long do_mbind(unsigned long start, unsigned long len, if (!list_empty(&pagelist)) { WARN_ON_ONCE(flags & MPOL_MF_LAZY); - nr_failed = migrate_pages(&pagelist, new_vma_page, - (unsigned long)vma, - MIGRATE_SYNC, MR_MEMPOLICY_MBIND); + nr_failed = migrate_pages(&pagelist, new_page, + start, MIGRATE_SYNC, MR_MEMPOLICY_MBIND); if (nr_failed) putback_movable_pages(&pagelist); } -- 2.0.0 -- 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/