From ff1a668bc01c811ffcf19a3d43af58d7bd658986 Mon Sep 17 00:00:00 2001 From: Radu Caragea Date: Wed, 21 Aug 2013 20:55:59 +0300 Subject: x86 get_unmapped_area: Access mmap_legacy_base through mm_struct member commit 41aacc1eea645c99edbe8fbcf78a97dc9b862adc upstream. This is the updated version of df54d6fa5427 ("x86 get_unmapped_area(): use proper mmap base for bottom-up direction") that only randomizes the mmap base address once. Signed-off-by: Radu Caragea Reported-and-tested-by: Jeff Shorey Cc: Andrew Morton Cc: Michel Lespinasse Cc: Oleg Nesterov Cc: Rik van Riel Cc: Ingo Molnar Cc: Adrian Sendroiu Cc: Kamal Mostafa Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/sys_x86_64.c | 2 +- arch/x86/mm/mmap.c | 6 ++++-- 2 files changed, 5 insertions(+), 3 deletions(-) (limited to 'arch') diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c index dbded5aedb8..30277e27431 100644 --- a/arch/x86/kernel/sys_x86_64.c +++ b/arch/x86/kernel/sys_x86_64.c @@ -101,7 +101,7 @@ static void find_start_end(unsigned long flags, unsigned long *begin, *begin = new_begin; } } else { - *begin = TASK_UNMAPPED_BASE; + *begin = current->mm->mmap_legacy_base; *end = TASK_SIZE; } } diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c index 845df6835f9..5c1ae28825c 100644 --- a/arch/x86/mm/mmap.c +++ b/arch/x86/mm/mmap.c @@ -112,12 +112,14 @@ static unsigned long mmap_legacy_base(void) */ void arch_pick_mmap_layout(struct mm_struct *mm) { + mm->mmap_legacy_base = mmap_legacy_base(); + mm->mmap_base = mmap_base(); + if (mmap_is_legacy()) { - mm->mmap_base = mmap_legacy_base(); + mm->mmap_base = mm->mmap_legacy_base; mm->get_unmapped_area = arch_get_unmapped_area; mm->unmap_area = arch_unmap_area; } else { - mm->mmap_base = mmap_base(); mm->get_unmapped_area = arch_get_unmapped_area_topdown; mm->unmap_area = arch_unmap_area_topdown; } -- cgit v1.2.3