x86/mm/numa: Fix 32-bit memblock range truncation bug on 32-bit NUMA kernels

The following commit:

  a0acda917284 ("acpi, numa, mem_hotplug: mark all nodes the kernel resides un-hotpluggable")

Introduced numa_clear_kernel_node_hotplug(), which function is executed
during early bootup, and which marks all currently reserved memblock
regions as hot-memory-unswappable as well.

y14sg1 <[email protected]> reported that when running 32-bit NUMA kernels,
the grsecurity/PAX kernel patch flagged a size overflow in this function:

  PAX: size overflow detected in function x86_numa_init arch/x86/mm/numa.c:691 [...]

... the reason for the overflow is that memblock_clear_hotplug() takes physical
addresses as arguments, while the start/end variables used by
numa_clear_kernel_node_hotplug() are 'unsigned long', which is 32-bit on PAE
kernels, but which has 64-bit physical addresses.

So on 32-bit PAE kernels that have physical memory above the 4GB boundary,
we truncate a 64-bit physical address range to 32 bits and pass it to
memblock_clear_hotplug(), which at minimum prevents the original memory-hotplug
bugfix from working, but might have other side effects as well.

The fix is to use the proper type to handle physical addresses, phys_addr_t.

Reported-by: y14sg1 <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Brad Spengler <[email protected]>
Cc: Chen Tang <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: PaX Team <[email protected]>
Cc: Taku Izumi <[email protected]>
Cc: Tang Chen <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Wen Congyang <[email protected]>
Cc: Yasuaki Ishimatsu <[email protected]>
Cc: Zhang Yanfei <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index c3b3f653ed0c..d04f8094bc23 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -469,7 +469,7 @@ static void __init numa_clear_kernel_node_hotplug(void)
 {
 	int i, nid;
 	nodemask_t numa_kernel_nodes = NODE_MASK_NONE;
-	unsigned long start, end;
+	phys_addr_t start, end;
 	struct memblock_region *r;
 
 	/*