[lkml]   [2007]   [Dec]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[patch 38/47] vmemmap: allocate struct pages before 1:1 mapping
From: Christian Borntraeger <>

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 <>
Signed-off-by: Martin Schwidefsky <>

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,

"Reality continues to ruin my life." - Calvin.

 \ /
  Last update: 2007-12-20 16:39    [W:0.110 / U:2.044 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site