Re: + arch-x86-mm-numa_32c-fix-the-initialization-of-physnode_map.patch added to -mm tree
On Mon, 3 Feb 2014, a...@linux-foundation.org wrote:
> From: Petr Tesarik
> Subject: arch/x86/mm/numa_32.c: fix the initialization of physnode_map
>
> With DISCONTIGMEM, the mapping between a pfn and its owning node is
> initialized using data provided by the BIOS. However, the initialization
> may fail if the extents are not aligned to section boundary (64M).
>
> The symptom of this bug is an early boot failure in pfn_to_page(), as it
> tries to access NODE_DATA(__nid) using index from an unitialized element
> of the physnode_map[] array.
>
> While the bug is always present, it is more likely to be hit in kdump
> kernels on large machines, because:
>
> 1. The memory map for a kdump kernel is specified as exactmap, and
>exactmap is more likely to be unaligned.
>
> 2. Large reservations are more likely to span across a 64M boundary.
>
> Signed-off-by: Petr Tesarik
> Signed-off-by: Andrew Morton
> ---
>
> arch/x86/mm/numa_32.c |2 ++
> 1 file changed, 2 insertions(+)
>
> diff -puN
> arch/x86/mm/numa_32.c~arch-x86-mm-numa_32c-fix-the-initialization-of-physnode_map
> arch/x86/mm/numa_32.c
> ---
> a/arch/x86/mm/numa_32.c~arch-x86-mm-numa_32c-fix-the-initialization-of-physnode_map
> +++ a/arch/x86/mm/numa_32.c
> @@ -52,6 +52,8 @@ void memory_present(int nid, unsigned lo
> nid, start, end);
> printk(KERN_DEBUG " Setting physnode_map array to node %d for
> pfns:\n", nid);
> printk(KERN_DEBUG " ");
> + pfn = round_down(pfn, PAGES_PER_SECTION);
> + end = round_up(end, PAGES_PER_SECTION);
> for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {
> physnode_map[pfn / PAGES_PER_SECTION] = nid;
> printk(KERN_CONT "%lx ", pfn);
This is the buggy version of the patch which erroneously rounds down the
uninitialized "pfn" rather than "start". hpa has already merged the
corrected patch into x86/urgent.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: + arch-x86-mm-numa_32c-fix-the-initialization-of-physnode_map.patch added to -mm tree
On Mon, 3 Feb 2014, a...@linux-foundation.org wrote:
From: Petr Tesarik ptesa...@suse.cz
Subject: arch/x86/mm/numa_32.c: fix the initialization of physnode_map
With DISCONTIGMEM, the mapping between a pfn and its owning node is
initialized using data provided by the BIOS. However, the initialization
may fail if the extents are not aligned to section boundary (64M).
The symptom of this bug is an early boot failure in pfn_to_page(), as it
tries to access NODE_DATA(__nid) using index from an unitialized element
of the physnode_map[] array.
While the bug is always present, it is more likely to be hit in kdump
kernels on large machines, because:
1. The memory map for a kdump kernel is specified as exactmap, and
exactmap is more likely to be unaligned.
2. Large reservations are more likely to span across a 64M boundary.
Signed-off-by: Petr Tesarik ptesa...@suse.cz
Signed-off-by: Andrew Morton a...@linux-foundation.org
---
arch/x86/mm/numa_32.c |2 ++
1 file changed, 2 insertions(+)
diff -puN
arch/x86/mm/numa_32.c~arch-x86-mm-numa_32c-fix-the-initialization-of-physnode_map
arch/x86/mm/numa_32.c
---
a/arch/x86/mm/numa_32.c~arch-x86-mm-numa_32c-fix-the-initialization-of-physnode_map
+++ a/arch/x86/mm/numa_32.c
@@ -52,6 +52,8 @@ void memory_present(int nid, unsigned lo
nid, start, end);
printk(KERN_DEBUG Setting physnode_map array to node %d for
pfns:\n, nid);
printk(KERN_DEBUG );
+ pfn = round_down(pfn, PAGES_PER_SECTION);
+ end = round_up(end, PAGES_PER_SECTION);
for (pfn = start; pfn end; pfn += PAGES_PER_SECTION) {
physnode_map[pfn / PAGES_PER_SECTION] = nid;
printk(KERN_CONT %lx , pfn);
This is the buggy version of the patch which erroneously rounds down the
uninitialized pfn rather than start. hpa has already merged the
corrected patch into x86/urgent.
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
