Re: [PATCH] mm: fix incorrect behavior when process virtual address space limit is exceeded

From: Chris Metcalf
Date: Tue Nov 17 2015 - 12:38:32 EST

On 11/17/2015 11:19 AM, Oleg Nesterov wrote:
On 11/16, Piotr Kwapulinski wrote:
@@ -1551,7 +1552,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
* MAP_FIXED may remove pages of mappings that intersects with
* requested mapping. Account for the pages it would unmap.
- if (!(vm_flags & MAP_FIXED))
+ if (!(flags & MAP_FIXED))
return -ENOMEM;
And afaics arch/tile/mm/elf.c can use do_mmap(MAP_FIXED ...) rather than
mmap_region(), it can be changed by a separate patch. In this case we can
unexport mmap_region().

The problem is that we are mapping a region of virtual address space that
the chip provides for setting up interrupt handlers (at 0xfc000000) but that
is above the TASK_SIZE cutoff, so do_mmap() would fail the call in

Chris Metcalf, EZChip Semiconductor

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at