From: Shaohua Li <shaohua.li@intel.com>
Date: Fri, 8 Dec 2006 10:41:13 +0000 (-0800)
Subject: [PATCH] CPU hotplug broken with 2GB VMSPLIT
X-Git-Tag: v2.6.20-rc1~34^2~42
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3b1bdf4e08d6a8d4fae5a30224ed2c55bf1e43fc;p=linux-2.6

[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>
---

diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c
index 4bf0e3c83b..1e00b03163 100644
--- a/arch/i386/kernel/smpboot.c
+++ b/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);