Re: Linux 3.4-rc7

From: Tobias Ulmer
Date: Sun May 13 2012 - 16:39:09 EST


On Mon, May 14, 2012 at 01:26:23AM +0530, Srivatsa S. Bhat wrote:
> On 05/13/2012 07:34 AM, Linus Torvalds wrote:
>
> > This is almost certainly the last -rc in this series - things really
> > have calmed down, and I even considered just cutting 3.4 this weekend,
> > but felt that another week wouldn't hurt.
> [...]
> > So go forth and test. And don't send me any pull requests unless they
> > contain *only* regressions or fixes for really nasty bugs.
>
>
> Oh, I just noticed that 2 important fixes which fix boot failures on
> PA-RISC and mn10300 architectures haven't made it to mainline yet.
>
> The regression was introduced in the 3.4 merge window itself (by commit
> 5fbd036b55 "sched: Cleanup cpu_active madness").
>
> Links to the original posting:
> PA_RISC: http://marc.info/?l=linux-parisc&m=133241790810604&w=2
> mn10300: http://marc.info/?l=linux-parisc&m=133241580509804&w=2
>
> Mikulas confirmed that this fixes the boot failure on PA-RISC:
> https://lkml.org/lkml/2012/5/8/97

Yes, indeed my c8000 boots again :-) Only had to add cpu.h for
notify_cpu_starting() to make it complile:

The scheduler depends on receiving the CPU_STARTING notification, without
which we end up into a lot of trouble. So add the missing call to
notify_cpu_starting() in the bringup code.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
Acked-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Acked-by: Tobias Ulmer <tobiasu@xxxxxxxx>
---
arch/parisc/kernel/smp.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 0bb1d63..4dc7b79 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -31,6 +31,7 @@
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/ftrace.h>
+#include <linux/cpu.h>

#include <linux/atomic.h>
#include <asm/current.h>
@@ -295,8 +296,13 @@ smp_cpu_init(int cpunum)

printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
machine_halt();
- }
+ }
+
+ notify_cpu_starting(cpunum);
+
+ ipi_call_lock();
set_cpu_online(cpunum, true);
+ ipi_call_unlock();

/* Initialise the idle task for this CPU */
atomic_inc(&init_mm.mm_count);
--
1.7.3.4


Thanks,
Tobias

>
> Regards,
> Srivatsa S. Bhat
>
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