From: Alexandre Ghiti <a...@ghiti.fr> [ Upstream commit 86e568e9c0525fc40e76d827212d5e9721cf7504 ]
mmap base address must be computed wrt stack top address, using TASK_SIZE is wrong since STACK_TOP and TASK_SIZE are not equivalent. Link: http://lkml.kernel.org/r/20190730055113.23635-8-a...@ghiti.fr Signed-off-by: Alexandre Ghiti <a...@ghiti.fr> Acked-by: Kees Cook <keesc...@chromium.org> Reviewed-by: Luis Chamberlain <mcg...@kernel.org> Cc: Albert Ou <a...@eecs.berkeley.edu> Cc: Alexander Viro <v...@zeniv.linux.org.uk> Cc: Catalin Marinas <catalin.mari...@arm.com> Cc: Christoph Hellwig <h...@infradead.org> Cc: Christoph Hellwig <h...@lst.de> Cc: James Hogan <jho...@kernel.org> Cc: Palmer Dabbelt <pal...@sifive.com> Cc: Paul Burton <paul.bur...@mips.com> Cc: Ralf Baechle <r...@linux-mips.org> Cc: Russell King <li...@armlinux.org.uk> Cc: Will Deacon <will.dea...@arm.com> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Sasha Levin <sas...@kernel.org> --- arch/arm/mm/mmap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c index bff3d00bda5be..0b94b674aa91f 100644 --- a/arch/arm/mm/mmap.c +++ b/arch/arm/mm/mmap.c @@ -19,7 +19,7 @@ /* 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) @@ -51,7 +51,7 @@ 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); } /* -- 2.20.1
