[PATCH v6 10/14] mips: Use STACK_TOP when computing mmap base address

From: Alexandre Ghiti
Date: Thu Aug 08 2019 - 02:29:13 EST


mmap base address must be computed wrt stack top address, using TASK_SIZE
is wrong since STACK_TOP and TASK_SIZE are not equivalent.

Signed-off-by: Alexandre Ghiti <alex@xxxxxxxx>
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
Acked-by: Paul Burton <paul.burton@xxxxxxxx>
Reviewed-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
---
arch/mips/mm/mmap.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
index f5c778113384..a7e84b2e71d7 100644
--- a/arch/mips/mm/mmap.c
+++ b/arch/mips/mm/mmap.c
@@ -22,7 +22,7 @@ EXPORT_SYMBOL(shm_align_mask);

/* gap between mmap and stack */
#define MIN_GAP (128*1024*1024UL)
-#define MAX_GAP ((TASK_SIZE)/6*5)
+#define MAX_GAP ((STACK_TOP)/6*5)
#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12))

static int mmap_is_legacy(struct rlimit *rlim_stack)
@@ -54,7 +54,7 @@ static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack)
else if (gap > MAX_GAP)
gap = MAX_GAP;

- return PAGE_ALIGN(TASK_SIZE - gap - rnd);
+ return PAGE_ALIGN(STACK_TOP - gap - rnd);
}

#define COLOUR_ALIGN(addr, pgoff) \
--
2.20.1