[PATCH] CPU hotplug broken with 2GB VMSPLIT

In VMSPLIT mode, kernel PGD might have more entries than user space.

Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/i386/kernel/smpboot.c

@@ -1118,7 +1118,7 @@ static int __cpuinit __smp_prepare_cpu(int cpu)
 
 	/* init low mem mapping */
 	clone_pgd_range(swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
-			KERNEL_PGD_PTRS);
+			min_t(unsigned long, KERNEL_PGD_PTRS, USER_PGD_PTRS));
 	flush_tlb_all();
 	schedule_work(&info.task);
 	wait_for_completion(&done);