Messages in this thread Patch in this message | | | Date | Wed, 7 Nov 2007 23:15:38 +0900 | From | "Akinobu Mita" <> | Subject | Re: [PATCH] x86: fix cpu-hotplug regression |
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> [PATCH] x86: fix cpu hotplug regression (don't call mce_create_device on CPU_UP_PREPARE) > > Fix regression introduced with d435d862baca3e25e5eec236762a43251b1e7ffc > ("cpu hotplug: mce: fix cpu hotplug error handling"). > > For CPUs not brought up during boot (using maxcpus and additional_cpus > parameters) we don't know whether mce is supported or not at "CPU_UP_PREPARE"-time. > Thus mce_cpu_callback should be called after the CPU is online.
Thank you for finding and fixing the problem. I added two fixes to your patch:
- Avoid mce_remove_device() for the CPU that is not correctly initialized by mce_create_device() failure.
- make CPU_ONLINE callback always return NOTIFY_OK. Because CPU_ONLINE callback return value is always ignored.
> Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
[akinobu.mita@gmail.com: make CPU_ONLINE callback always return NOTIFY_OK] [akinobu.mita@gmail.com: avoid mce_remove_device() for not initialized device]
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
--- arch/x86/kernel/cpu/mcheck/mce_64.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-)
Index: 2.6-git/arch/x86/kernel/cpu/mcheck/mce_64.c =================================================================== --- 2.6-git.orig/arch/x86/kernel/cpu/mcheck/mce_64.c +++ 2.6-git/arch/x86/kernel/cpu/mcheck/mce_64.c @@ -802,6 +802,8 @@ static struct sysdev_attribute *mce_attr NULL };
+static cpumask_t mce_device_initialized = CPU_MASK_NONE; + /* Per cpu sysdev init. All of the cpus still share the same ctl bank */ static __cpuinit int mce_create_device(unsigned int cpu) { @@ -825,6 +827,7 @@ static __cpuinit int mce_create_device(u if (err) goto error; } + cpu_set(cpu, mce_device_initialized);
return 0; error: @@ -841,10 +844,14 @@ static void mce_remove_device(unsigned i { int i;
+ if (!cpu_isset(cpu, mce_device_initialized)) + return; + for (i = 0; mce_attributes[i]; i++) sysdev_remove_file(&per_cpu(device_mce,cpu), mce_attributes[i]); sysdev_unregister(&per_cpu(device_mce,cpu)); + cpu_clear(cpu, mce_device_initialized); }
/* Get notified when a cpu comes on/off. Be hotplug friendly. */ @@ -852,21 +859,18 @@ static int mce_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) { unsigned int cpu = (unsigned long)hcpu; - int err = 0;
switch (action) { - case CPU_UP_PREPARE: - case CPU_UP_PREPARE_FROZEN: - err = mce_create_device(cpu); + case CPU_ONLINE: + case CPU_ONLINE_FROZEN: + mce_create_device(cpu); break; - case CPU_UP_CANCELED: - case CPU_UP_CANCELED_FROZEN: case CPU_DEAD: case CPU_DEAD_FROZEN: mce_remove_device(cpu); break; } - return err ? NOTIFY_BAD : NOTIFY_OK; + return NOTIFY_OK; }
static struct notifier_block mce_cpu_notifier = { - 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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