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authorJonathan Steel <jon.steel@esentire.com>2008-09-22 13:57:45 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-09-23 08:09:14 -0700
commitf9092f358bc2ec5367621478811f046f82873376 (patch)
tree12c91aff3aa1d32b2f747470c160093aab6bdabe /kernel/kexec.c
parent39f00c087d31f668eb6eaf97508af22a32c5b1d9 (diff)
kexec: fix segmentation fault in kimage_add_entry
A segmentation fault can occur in kimage_add_entry in kexec.c when loading a kernel image into memory. The fault occurs because a page is requested by calling kimage_alloc_page with gfp_mask GFP_KERNEL and the function may actually return a page with gfp_mask GFP_HIGHUSER. The high mem page is returned because it was swapped with the kernel page due to the kernel page being a page that will shortly be copied to. This patch ensures that kimage_alloc_page returns a page that was created with the correct gfp flags. I have verified the change and fixed the whitespace damage of the original patch. Jonathan did a great job of tracking this down after he hit the problem. -- Eric Signed-off-by: Jonathan Steel <jon.steel@esentire.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Simon Horman <horms@verge.net.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/kexec.c')
-rw-r--r--kernel/kexec.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 59f3f0df35d4..aef265325cd3 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -753,8 +753,14 @@ static struct page *kimage_alloc_page(struct kimage *image,
*old = addr | (*old & ~PAGE_MASK);
/* The old page I have found cannot be a
- * destination page, so return it.
+ * destination page, so return it if it's
+ * gfp_flags honor the ones passed in.
*/
+ if (!(gfp_mask & __GFP_HIGHMEM) &&
+ PageHighMem(old_page)) {
+ kimage_free_pages(old_page);
+ continue;
+ }
addr = old_addr;
page = old_page;
break;