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authorIngo Molnar <mingo@kernel.org>2016-02-08 08:47:48 +0100
committerIngo Molnar <mingo@kernel.org>2016-02-08 12:10:03 +0100
commit59fd1214561921343305a0e9dc218bf3d40068f3 (patch)
treee35ddc812e3aa13b08ae2227e544390eae723043 /arch/x86
parentx86: Fix KASAN false positives in thread_saved_pc() (diff)
downloadlinux-59fd1214561921343305a0e9dc218bf3d40068f3.tar.xz
linux-59fd1214561921343305a0e9dc218bf3d40068f3.zip
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 <y14sg1@comcast.net> 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 <y14sg1@comcast.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Brad Spengler <spender@grsecurity.net> Cc: Chen Tang <imtangchen@gmail.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: PaX Team <pageexec@freemail.hu> Cc: Taku Izumi <izumi.taku@jp.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/mm/numa.c2
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;
/*