When checking for overflow, the code in mm/mmap.c compares the first byte
*after* the end of mapped region to the start of the region instead of the
last byte of the mapped region. This prevents mapping a region which abuts
the end of physical space, as mmap() incorrectly rejects the region with
-EOVERFLOW, because pgoff + (len >> PAGE_SHIFT) will be 0, which is < pgoff.
-reese
Reese Faucette
Cisco Systems, Inc.
====================================================
--- mm/mmap.c
+++ mm/mmap.c
@@ -1241,7 +1241,7 @@
return -ENOMEM;
/* offset overflow? */
- if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
+ if ((pgoff + (len >> PAGE_SHIFT) - 1) < pgoff)
return -EOVERFLOW;
/* Too many mappings? */
--
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