From: Will Deacon Date: Fri, 8 Feb 2013 11:52:29 +0000 (+0100) Subject: ARM: 7641/1: memory: fix broken mmap by ensuring TASK_UNMAPPED_BASE is aligned X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=79d1f5c9acf9fc8d06e5537083b19114ce87159f;p=linux-beck.git ARM: 7641/1: memory: fix broken mmap by ensuring TASK_UNMAPPED_BASE is aligned We have received multiple reports of mmap failures when running with a 2:2 vm split. These manifest as either -EINVAL with a non page-aligned address (ending 0xaaa) or a SEGV, depending on the application. The issue is commonly observed in children of make, which appears to use bottom-up mmap (assumedly because it changes the stack rlimit). Further investigation reveals that this regression was triggered by 394ef6403abc ("mm: use vm_unmapped_area() on arm architecture"), whereby TASK_UNMAPPED_BASE is no longer page-aligned for bottom-up mmap, causing get_unmapped_area to choke on misaligned addressed. This patch fixes the problem by defining TASK_UNMAPPED_BASE in terms of TASK_SIZE and explicitly aligns the result to 16M, matching the other end of the heap. Acked-by: Nicolas Pitre Reported-by: Steve Capper Reported-by: Jean-Francois Moine Reported-by: Christoffer Dall Signed-off-by: Will Deacon Signed-off-by: Russell King --- diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h index 73cf03aa981e..1c4df27f9332 100644 --- a/arch/arm/include/asm/memory.h +++ b/arch/arm/include/asm/memory.h @@ -37,7 +37,7 @@ */ #define PAGE_OFFSET UL(CONFIG_PAGE_OFFSET) #define TASK_SIZE (UL(CONFIG_PAGE_OFFSET) - UL(0x01000000)) -#define TASK_UNMAPPED_BASE (UL(CONFIG_PAGE_OFFSET) / 3) +#define TASK_UNMAPPED_BASE ALIGN(TASK_SIZE / 3, SZ_16M) /* * The maximum size of a 26-bit user space task.