>From baa30fb2027096d6604c9f0ba2bad04a30edc482 Mon Sep 17 00:00:00 2001 From: Stefan Bader Date: Tue, 31 Aug 2010 13:59:58 +0200 Subject: [PATCH] mm: Fix hiding the stack guard page in proc Commit d7824370e26325c881b665350ce64fb0a4fde24a tried to hide the stack guard page from user-space by adapting mlock and hiding it in /proc. Commit 7798330ac8114c731cfab83e634c6ecedaa233d7 fixed the mlock part, using the newly added double linked vma lists. Still the proc change would hide the first page of each stack vma which would be wrong for those vmas that are just continuations of the stack after its vma has been split. Signed-off-by: Stefan Bader Cc: stable@kernel.org --- fs/proc/task_mmu.c | 4 +++- 1 files changed, 3 insertions(+), 1 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 439fc1f..2e302b4 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -224,7 +224,9 @@ static void show_map_vma(struct seq_file *m, struct vm_area_struct *vma) /* We don't show the stack guard page in /proc/maps */ start = vma->vm_start; if (vma->vm_flags & VM_GROWSDOWN) - start += PAGE_SIZE; + if (!vma->vm_prev || vma->vm_prev->vm_flags != VM_GROWSDOWN || + vma->vm_start != vma->vm_prev->vm_end) + start += PAGE_SIZE; seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n", start, -- 1.7.0.4