[PATCH 5/9] x86-64 fix smp boot failure with thread_info change

From: Benjamin LaHaise (bcrl_at_kvack.org)
Date: 11/30/05

  • Next message: Tejun Heo: "Re: totally random "VFS: Cannot open root device"" 
    Date:	Tue, 29 Nov 2005 23:21:48 -0500
To: Andi Kleen <ak@suse.de>

    Make sure that stack_smp_processor_id() gets set for all CPUs regardless of
    which path we take in do_boot_cpu(), as well as in upcoming case where
    tsk->thread_info != task_thread_info(tsk).

    Add a memory barrier to ensure this change is flushed before the other
    CPU comes up. My P4/HT machine was occasionally randomly failing to boot
    without this barrier. 

    ---
 arch/x86_64/kernel/smpboot.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
applies-to: ff25c960b7af25819aba4fbecbd94bd3500a3a4a
932262b117ba1c3a77078b64674e1a1823c169df
diff --git a/arch/x86_64/kernel/smpboot.c b/arch/x86_64/kernel/smpboot.c
index 50d018a..10b951b 100644
--- a/arch/x86_64/kernel/smpboot.c
+++ b/arch/x86_64/kernel/smpboot.c
@@ -780,6 +780,9 @@ do_rest:
 
 	cpu_pda[cpu].pcurrent = c_idle.idle;
 
+	/* set the CPU for stack_smp_processor_id() */
+	c_idle.idle->thread_info->cpu = cpu;
+
 	start_rip = setup_trampoline();
 
 	init_rsp = c_idle.idle->thread.rsp;
@@ -796,6 +799,7 @@ do_rest:
 	 * the targeted processor.
 	 */
 
+	mb();
 	atomic_set(&init_deasserted, 0);
 
 	Dprintk("Setting warm reset code and vector.\n");
---
0.99.9.GIT
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/
  • Next message: Tejun Heo: "Re: totally random "VFS: Cannot open root device""