| Message ID | 1423577390-25487-1-git-send-email-luis.henriques@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/mm/pagewalk.c b/mm/pagewalk.c index 2beeabf502c5..9056d22d2880 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -199,7 +199,10 @@ int walk_page_range(unsigned long addr, unsigned long end, */ if ((vma->vm_start <= addr) && (vma->vm_flags & VM_PFNMAP)) { - next = vma->vm_end; + if (walk->pte_hole) + err = walk->pte_hole(addr, next, walk); + if (err) + break; pgd = pgd_offset(walk->mm, next); continue; }
This is a note to let you know that I have just added a patch titled mm: pagewalk: call pte_hole() for VM_PFNMAP during walk_page_range to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt7. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From 48596119928ea8232968de454da1b1cd2e0b17a3 Mon Sep 17 00:00:00 2001 From: Shiraz Hashim <shashim@codeaurora.org> Date: Thu, 5 Feb 2015 12:25:06 -0800 Subject: mm: pagewalk: call pte_hole() for VM_PFNMAP during walk_page_range commit 23aaed6659df9adfabe9c583e67a36b54e21df46 upstream. walk_page_range() silently skips vma having VM_PFNMAP set, which leads to undesirable behaviour at client end (who called walk_page_range). Userspace applications get the wrong data, so the effect is like just confusing users (if the applications just display the data) or sometimes killing the processes (if the applications do something with misunderstanding virtual addresses due to the wrong data.) For example for pagemap_read, when no callbacks are called against VM_PFNMAP vma, pagemap_read may prepare pagemap data for next virtual address range at wrong index. Eventually userspace may get wrong pagemap data for a task. Corresponding to a VM_PFNMAP marked vma region, kernel may report mappings from subsequent vma regions. User space in turn may account more pages (than really are) to the task. In my case I was using procmem, procrack (Android utility) which uses pagemap interface to account RSS pages of a task. Due to this bug it was giving a wrong picture for vmas (with VM_PFNMAP set). Fixes: a9ff785e4437 ("mm/pagewalk.c: walk_page_range should avoid VM_PFNMAP areas") Signed-off-by: Shiraz Hashim <shashim@codeaurora.org> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- mm/pagewalk.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) -- 2.1.4