From: Lin Chen <linx.z.c...@intel.com>
We hit a panic while doing cpu hotplug test.
<0>[ 627.982857] Kernel panic - not syncing: smp_callin: CPU1 started up but
did not get a callout!
<0>[ 627.982864]
<4>[ 627.982876] Pid: 0, comm: kworker/0:1 Tainted: G ...
<4>[ 627.982883] Call Trace:
<4>[ 627.982903] [<c18f2977>] panic+0x66/0x16c
<4>[ 627.982918] [<c12234cc>] ? default_get_apic_id+0x1c/0x40
<4>[ 627.982931] [<c18ef96d>] start_secondary+0xda/0x252
During BSP bootup AP, it is possible that BSP be preempted before
finishing STARTUP sequence of AP(set cpu_callout_mask) which maybe cause
AP busy wait for it. At present, AP will wait for 2 seconds then panic.
This patch let AP waits until BSP finish the startup sequence and gives
WARNING when BSP is preempted more than 2 seconds.
Signed-off-by: Yanmin Zhang <yanmin_zh...@linux.intel.com>
Signed-off-by: Lin Chen <linx.z.c...@intel.com>
---
arch/x86/kernel/smpboot.c | 11 ++++++-----
1 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 7c5a8c3..a9e3379 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -165,19 +165,20 @@ static void __cpuinit smp_callin(void)
* Waiting 2s total for startup (udelay is not yet working)
*/
timeout = jiffies + 2*HZ;
- while (time_before(jiffies, timeout)) {
+ while (1) {
/*
* Has the boot CPU finished it's STARTUP sequence?
*/
if (cpumask_test_cpu(cpuid, cpu_callout_mask))
break;
cpu_relax();
+ if (!time_before(jiffies, timeout)) {
+ WARN(1, "%s: CPU%d started up but did not get a
callout!\n",
+ __func__, cpuid);
+ timeout = jiffies + 2*HZ;
+ }
}
- if (!time_before(jiffies, timeout)) {
- panic("%s: CPU%d started up but did not get a callout!\n",
- __func__, cpuid);
- }
/*
* the boot CPU has finished the init stage and is spinning
--
1.7.1
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