Messages in this thread Patch in this message | | | Date | Wed, 7 Mar 2007 18:12:31 +0100 | From | Ingo Molnar <> | Subject | [patch] CPU hotplug: call check_tsc_sync_source() with irqs off |
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* Linus Torvalds <torvalds@linux-foundation.org> wrote:
> [ Ingo and Thomas added to Cc, because I think this is them.. ] > > Ingo, I think this came in during commit 95492e4646, "x86: rewrite SMP > TSC sync code".
yeah.
> > I get this while > > echo shutdown > /sys/power/disk; echo disk > /sys/power/state > > > > BUG: using smp_processor_id() in preemptible [00000001] code: swsusp_shutdown/3359 > > caller is check_tsc_sync_source+0x1b/0xef
Michal, could you try the patch below?
Ingo
-----------------------------> Subject: [patch] CPU hotplug: call check_tsc_sync_source() with irqs off From: Ingo Molnar <mingo@elte.hu>
check_tsc_sync_source() depends on being called with irqs disabled (it checks whether the TSC is coherent across two specific CPUs). This is incidentally true during bootup, but not during cpu hotplug __cpu_up(). This got found via smp_processor_id() debugging.
disable irqs explicitly and remove the unconditional enabling of interrupts. Add touch_nmi_watchdog() to the cpu_online_map busy loop.
this bug is present both on i386 and on x86_64.
Reported-by: Michal Piotrowski <michal.k.k.piotrowski@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> --- arch/i386/kernel/smpboot.c | 16 ++++++++++------ arch/x86_64/kernel/smpboot.c | 5 ++++- 2 files changed, 14 insertions(+), 7 deletions(-)
Index: linux/arch/i386/kernel/smpboot.c =================================================================== --- linux.orig/arch/i386/kernel/smpboot.c +++ linux/arch/i386/kernel/smpboot.c @@ -50,6 +50,7 @@ #include <linux/notifier.h> #include <linux/cpu.h> #include <linux/percpu.h> +#include <linux/nmi.h> #include <linux/delay.h> #include <linux/mc146818rtc.h> @@ -1283,8 +1284,9 @@ void __cpu_die(unsigned int cpu) int __cpuinit __cpu_up(unsigned int cpu) { + unsigned long flags; #ifdef CONFIG_HOTPLUG_CPU - int ret=0; + int ret = 0; /* * We do warm boot only on cpus that had booted earlier @@ -1302,23 +1304,25 @@ int __cpuinit __cpu_up(unsigned int cpu) /* In case one didn't come up */ if (!cpu_isset(cpu, cpu_callin_map)) { printk(KERN_DEBUG "skipping cpu%d, didn't come online\n", cpu); - local_irq_enable(); return -EIO; } - local_irq_enable(); - per_cpu(cpu_state, cpu) = CPU_UP_PREPARE; /* Unleash the CPU! */ cpu_set(cpu, smp_commenced_mask); /* - * Check TSC synchronization with the AP: + * Check TSC synchronization with the AP (keep irqs disabled + * while doing so): */ + local_irq_save(flags); check_tsc_sync_source(cpu); + local_irq_restore(flags); - while (!cpu_isset(cpu, cpu_online_map)) + while (!cpu_isset(cpu, cpu_online_map)) { cpu_relax(); + touch_nmi_watchdog(); + } #ifdef CONFIG_X86_GENERICARCH if (num_online_cpus() > 8 && genapic == &apic_default) Index: linux/arch/x86_64/kernel/smpboot.c =================================================================== --- linux.orig/arch/x86_64/kernel/smpboot.c +++ linux/arch/x86_64/kernel/smpboot.c @@ -923,8 +923,9 @@ void __init smp_prepare_boot_cpu(void) */ int __cpuinit __cpu_up(unsigned int cpu) { - int err; int apicid = cpu_present_to_apicid(cpu); + unsigned long flags; + int err; WARN_ON(irqs_disabled()); @@ -958,7 +959,9 @@ int __cpuinit __cpu_up(unsigned int cpu) /* * Make sure and check TSC sync: */ + local_irq_save(flags); check_tsc_sync_source(cpu); + local_irq_restore(flags); while (!cpu_isset(cpu, cpu_online_map)) cpu_relax(); - 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/
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