From 59fd1214561921343305a0e9dc218bf3d40068f3 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 8 Feb 2016 08:47:48 +0100 Subject: 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 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 Cc: Andrew Morton Cc: Brad Spengler Cc: Chen Tang Cc: "H. Peter Anvin" Cc: Lai Jiangshan Cc: Linus Torvalds Cc: PaX Team Cc: Taku Izumi Cc: Tang Chen Cc: Thomas Gleixner Cc: Wen Congyang Cc: Yasuaki Ishimatsu Cc: Zhang Yanfei Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- arch/x86/mm/numa.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86') 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; /* -- cgit v1.2.3