dom0less boot two compressed kernel images out-of-memory work-around

[Charles Chiou <cchiou@xxxxxxxxxxxxx>]

Hello,

When trying to boot two zImage using dom0less boot on ARM, we encountered this 
problem when xen runs gunzip on second guest:

(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) Out of memory
(XEN) ****************************************

And worked around it with the following patch. We'd like to check to see if 
this is a known issue and if the work-around looks reasonable. Thank you


diff --git a/xen/common/gunzip.c b/xen/common/gunzip.c
index db4efcd34b..e5bd19ba7f 100644
--- a/xen/common/gunzip.c
+++ b/xen/common/gunzip.c
@@ -113,8 +113,10 @@ __init int perform_gunzip(char *output, char *image, 
unsigned long image_len)

     window = (unsigned char *)output;

+    if (!free_mem_ptr) {
         free_mem_ptr = (unsigned long)alloc_xenheap_pages(HEAPORDER, 0);
         free_mem_end_ptr = free_mem_ptr + (PAGE_SIZE << HEAPORDER);
+    }

     inbuf = (unsigned char *)image;
     insize = image_len;
@@ -131,7 +133,12 @@ __init int perform_gunzip(char *output, char *image, 
unsigned long image_len)
         rc = 0;
     }

+    if (free_mem_ptr) {
         free_xenheap_pages((void *)free_mem_ptr, HEAPORDER);
+        free_mem_ptr = 0;
+    }
+
+    bytes_out = 0;

     return rc;
}
diff --git a/xen/common/inflate.c b/xen/common/inflate.c
index f99c985d61..de96002188 100644
--- a/xen/common/inflate.c
+++ b/xen/common/inflate.c
@@ -244,7 +244,7 @@ static void *INIT malloc(int size)

     if (size < 0)
         error("Malloc error");
-    if (!malloc_ptr)
+    if ((!malloc_ptr) || (!malloc_count))
         malloc_ptr = free_mem_ptr;

     malloc_ptr = (malloc_ptr + 3) & ~3;     /* Align */

--
Charles Chiou


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