Messages in this thread Patch in this message | | | Date | Tue, 07 Aug 2012 18:50:40 +0900 | From | "Chen, LinX Z" <> | Subject | [PATCH] x86/smp: Fix cpuN startup panic |
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From: Lin Chen <linx.z.chen@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_zhang@linux.intel.com> Signed-off-by: Lin Chen <linx.z.chen@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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