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x86, kdump: fix invalid access on i386 sparsemem

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Impact: fix kdump crash on 32-bit sparsemem kernels

Since linux-2.6.27, kdump has failed on i386 sparsemem kernel.
1st-kernel gets a panic just before switching to 2nd-kernel.

The cause is that a kernel accesses invalid mem_section by
page_to_pfn(image->swap_page) at machine_kexec().
image->swap_page is allocated if kexec for hibernation, but
it is not allocated if kdump. So if kdump, a kernel should
not access the mem_section corresponding to image->swap_page.

The attached patch fixes this invalid access.

Signed-off-by: Ken'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp>
Cc: kexec-ml <kexec@lists.infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ken'ichi Ohmichi 2008-10-20 13:51:52 +09:00 committed by Ingo Molnar
parent 1281675e9c
commit e7706fc691
1 changed files with 4 additions and 1 deletions
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5
arch/x86/kernel/machine_kexec_32.c
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@ -162,7 +162,10 @@ void machine_kexec(struct kimage *image)
page_list[VA_PTE_0] = (unsigned long)kexec_pte0;
page_list[PA_PTE_1] = __pa(kexec_pte1);
page_list[VA_PTE_1] = (unsigned long)kexec_pte1;
page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page) << PAGE_SHIFT);
if (image->type == KEXEC_TYPE_DEFAULT)
page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
<< PAGE_SHIFT);
/* The segment registers are funny things, they have both a
* visible and an invisible part. Whenever the visible part is