From: Christian Borntraeger <[email protected]>
We have seen an oops in an OOM situation, where show_mem tried to
access the struct page of a dcss segment. The vmemmap code has
already created the 1:1 mapping but failed allocating the struct
pages. In the OOM case, show_mem now walks the memory. It uses
pfn_valid to detect if it may access the struct page. In the case
described above, the mapping was established and pfn_valid returned
true. As the struct pages were not allocated, the kernel oopsed.
We have to ensure that we have created the struct pages, before we
add a mapping pointing to the pages.
Signed-off-by: Christian Borntraeger <[email protected]>
Signed-off-by: Martin Schwidefsky <[email protected]>
---
arch/s390/mm/vmem.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
Index: quilt-2.6/arch/s390/mm/vmem.c
===================================================================
--- quilt-2.6.orig/arch/s390/mm/vmem.c
+++ quilt-2.6/arch/s390/mm/vmem.c
@@ -236,10 +236,10 @@ static int vmem_add_mem(unsigned long st
{
int ret;
- ret = vmem_add_range(start, size);
+ ret = vmem_add_mem_map(start, size);
if (ret)
return ret;
- return vmem_add_mem_map(start, size);
+ return vmem_add_range(start, size);
}
/*
--
blue skies,
Martin.
"Reality continues to ruin my life." - Calvin.