The patch titled
kexec: fix segmentation fault in kimage_add_entry
has been added to the -mm tree. Its filename is
kexec-segmentation-fault-in-kimage_add_entry.patch
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------------------------------------------------------
Subject: kexec: fix segmentation fault in kimage_add_entry
From: Jonathan Steel <jon.steel@xxxxxxxxxxxx>
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@xxxxxxxxxxxx>
Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/kexec.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff -puN kernel/kexec.c~kexec-segmentation-fault-in-kimage_add_entry kernel/kexec.c
--- a/kernel/kexec.c~kexec-segmentation-fault-in-kimage_add_entry
+++ a/kernel/kexec.c
@@ -753,8 +753,14 @@ static struct page *kimage_alloc_page(st
*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;
_
Patches currently in -mm which might be from jon.steel@xxxxxxxxxxxx are
kexec-segmentation-fault-in-kimage_add_entry.patch
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