3.2.51-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Radu Caragea <sinaelgl@xxxxxxxxx>
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 <sinaelgl@xxxxxxxxx>
Reported-and-tested-by: Jeff Shorey <shoreyjeff@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Michel Lespinasse <walken@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Adrian Sendroiu <molecula2788@xxxxxxxxx>
Cc: Greg KH <greg@xxxxxxxxx>
Cc: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
arch/x86/kernel/sys_x86_64.c | 2 +-
arch/x86/mm/mmap.c | 6 ++++--
include/linux/mm_types.h | 1 +
3 files changed, 6 insertions(+), 3 deletions(-)
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -115,7 +115,7 @@ static void find_start_end(unsigned long
*begin = new_begin;
}
} else {
- *begin = TASK_UNMAPPED_BASE;
+ *begin = current->mm->mmap_legacy_base;
*end = TASK_SIZE;
}
}
--- a/arch/x86/mm/mmap.c
+++ b/arch/x86/mm/mmap.c
@@ -112,12 +112,14 @@ static unsigned long mmap_legacy_base(vo
*/
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;
}
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -297,6 +297,7 @@ struct mm_struct {
void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
#endif
unsigned long mmap_base; /* base of mmap area */
+ unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
unsigned long task_size; /* size of task vm space */
unsigned long cached_hole_size; /* if non-zero, the largest hole below free_area_cache */
unsigned long free_area_cache; /* first hole of size cached_hole_size or larger */
--
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