| Message ID | 20190612044506.16392-3-nathanl@linux.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | e59a175faa8df9d674247946f2a5a9c29c835725 |
| Headers | show |
| Series | live partition migration vs cacheinfo | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch next (a3bf9fbdad600b1e4335dd90979f8d6072e4f602) |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 26 lines checked |
Hello Nathan, On Wed, Jun 12, 2019 at 10:19 AM Nathan Lynch <nathanl@linux.ibm.com> wrote: > > CPU online/offline code paths are sensitive to parts of the device > tree (various cpu node properties, cache nodes) that can be changed as > a result of a migration. > > Prevent CPU hotplug while the device tree potentially is inconsistent. > > Fixes: 410bccf97881 ("powerpc/pseries: Partition migration in the kernel") > Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com> Audited the callbacks of of_reconfig_notify(). We are fine with respect to CPU-Hotplug locking. Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> > --- > arch/powerpc/platforms/pseries/mobility.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c > index 88925f8ca8a0..edc1ec408589 100644 > --- a/arch/powerpc/platforms/pseries/mobility.c > +++ b/arch/powerpc/platforms/pseries/mobility.c > @@ -9,6 +9,7 @@ > * 2 as published by the Free Software Foundation. > */ > > +#include <linux/cpu.h> > #include <linux/kernel.h> > #include <linux/kobject.h> > #include <linux/smp.h> > @@ -338,11 +339,19 @@ void post_mobility_fixup(void) > if (rc) > printk(KERN_ERR "Post-mobility activate-fw failed: %d\n", rc); > > + /* > + * We don't want CPUs to go online/offline while the device > + * tree is being updated. > + */ > + cpus_read_lock(); > + > rc = pseries_devicetree_update(MIGRATION_SCOPE); > if (rc) > printk(KERN_ERR "Post-mobility device tree update " > "failed: %d\n", rc); > > + cpus_read_unlock(); > + > /* Possibly switch to a new RFI flush type */ > pseries_setup_rfi_flush(); > > -- > 2.20.1 >
diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c index 88925f8ca8a0..edc1ec408589 100644 --- a/arch/powerpc/platforms/pseries/mobility.c +++ b/arch/powerpc/platforms/pseries/mobility.c @@ -9,6 +9,7 @@ * 2 as published by the Free Software Foundation. */ +#include <linux/cpu.h> #include <linux/kernel.h> #include <linux/kobject.h> #include <linux/smp.h> @@ -338,11 +339,19 @@ void post_mobility_fixup(void) if (rc) printk(KERN_ERR "Post-mobility activate-fw failed: %d\n", rc); + /* + * We don't want CPUs to go online/offline while the device + * tree is being updated. + */ + cpus_read_lock(); + rc = pseries_devicetree_update(MIGRATION_SCOPE); if (rc) printk(KERN_ERR "Post-mobility device tree update " "failed: %d\n", rc); + cpus_read_unlock(); + /* Possibly switch to a new RFI flush type */ pseries_setup_rfi_flush();
CPU online/offline code paths are sensitive to parts of the device tree (various cpu node properties, cache nodes) that can be changed as a result of a migration. Prevent CPU hotplug while the device tree potentially is inconsistent. Fixes: 410bccf97881 ("powerpc/pseries: Partition migration in the kernel") Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com> --- arch/powerpc/platforms/pseries/mobility.c | 9 +++++++++ 1 file changed, 9 insertions(+)