lkml.org 
[lkml]   [2014]   [Apr]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v4 2/5] x86: fix memory corruption in acpi_unmap_lsapic()
Date
if during CPU hotplug master CPU failed to wake up AP
it set percpu x86_cpu_to_apicid to BAD_APICID=0xFFFF for AP.

However following attempt to unplug that CPU will lead to
out of bound write access to __apicid_to_node[] which is
32768 items long on x86_64 kernel.

So drop setting x86_cpu_to_apicid to BAD_APICID in do_boot_cpu()
and allow acpi_processor_remove()->acpi_unmap_lsapic() cleanly
remove CPU.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
arch/x86/kernel/smpboot.c | 2 --
1 files changed, 0 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 6124f15..2988f69 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -859,8 +859,6 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle)

/* was set by cpu_init() */
cpumask_clear_cpu(cpu, cpu_initialized_mask);
-
- per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID;
}

/* mark "stuck" area as not stuck */
--
1.7.1


\
 
 \ /
  Last update: 2014-04-14 17:41    [W:0.107 / U:0.456 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site