ARM: 7641/1: memory: fix broken mmap by ensuring TASK_UNMAPPED_BASE is aligned
authorWill Deacon <>
Fri, 8 Feb 2013 11:52:29 +0000 (12:52 +0100)
committerRussell King <>
Fri, 8 Feb 2013 12:21:07 +0000 (12:21 +0000)
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 <>

index 73cf03aa981e1b665d9a40f4f80847335ca49441..1c4df27f93322604398d70f9c585332e97374b10 100644 (file)
@@ -37,7 +37,7 @@
 #define TASK_SIZE              (UL(CONFIG_PAGE_OFFSET) - UL(0x01000000))
  * The maximum size of a 26-bit user space task.