[PATCH V3] xen: Check if the range is valid in init_domheap_pages

* [PATCH V3] xen: Check if the range is valid in init_domheap_pages
@ 2013-11-13 13:37 Julien Grall
  2013-11-13 14:58 ` Keir Fraser
  2013-11-20 16:09 ` Julien Grall
  0 siblings, 2 replies; 4+ messages in thread
From: Julien Grall @ 2013-11-13 13:37 UTC (permalink / raw)
  To: xen-devel
  Cc: Keir Fraser, ian.campbell, stefano.stabellini, Julien Grall, tim,
	Jan Beulich, patches

On ARM, when an initrd is given to xen by U-boot, it will reserve the memory in
the device tree.
In this case, when xen decides to free unused memory, dt_unreserved_regions
will call init_domheap_pages with the start and the end of range equals. But
the latter assumes that (start > end), if not Xen will hang because the
number of pages is equals to (unsigned)-1.

Signed-off-by: Julien Grall <julien.grall@linaro.org>
CC: Keir Fraser <keir@xen.org>
CC: Jan Beulich <jbeulich@suse.com>

---
    Changes in v3:
        - Invert the check

    Changes in v2:
        - Change commit title
        - Move the check in init_domheap_pages
---
 xen/common/page_alloc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index 4c17fbd..0701333 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -1429,6 +1429,9 @@ void init_domheap_pages(paddr_t ps, paddr_t pe)
     smfn = round_pgup(ps) >> PAGE_SHIFT;
     emfn = round_pgdown(pe) >> PAGE_SHIFT;
 
+    if ( emfn <= smfn )
+        return;
+
     init_heap_pages(mfn_to_page(smfn), emfn - smfn);
 }
 
-- 
1.8.3.1

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