Satyam Sharma wrote:
>> ------------[ cut here ]------------
>> Badness at arch/powerpc/kernel/smp.c:202
>>
>
> comes when smp_call_function_map() has been called with irqs disabled,
> which is illegal. However, there is a special case, the panic() codepath,
> when we do not want to warn about this -- warning at that time is pointless
> anyway, and only serves to scroll away the *real* cause of the panic and
> distracts from the real bug.
>
> * So let's extract the WARN_ON() from smp_call_function_map() into all its
> callers -- smp_call_function() and smp_call_function_single()
>
> * Also, introduce another caller of smp_call_function_map(), namely
> __smp_call_function() (and make smp_call_function() a wrapper over this)
> which does *not* warn about disabled irqs
>
> * Use this __smp_call_function() from the panic codepath's smp_send_stop()
>
> We also end having to move code of smp_send_stop() below the definition
> of __smp_call_function().
>
> Signed-off-by: Satyam Sharma <[email protected]>
>
> ---
>
> Untested (not even compile-tested) patch.
> Could someone point me to ppc32/64 cross-compilers for i386?
>
> arch/powerpc/kernel/smp.c | 27 ++++++++++++++++++---------
> 1 files changed, 18 insertions(+), 9 deletions(-)
>
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index 1ea4316..b24dcba 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -152,11 +152,6 @@ static void stop_this_cpu(void *dummy)
> ;
> }
>
> -void smp_send_stop(void)
> -{
> - smp_call_function(stop_this_cpu, NULL, 1, 0);
> -}
> -
> /*
> * Structure and data for smp_call_function(). This is designed to minimise
> * static memory requirements. It also looks cleaner.
> @@ -198,9 +193,6 @@ int smp_call_function_map(void (*func) (void *info), void *info, int nonatomic,
> int cpu;
> u64 timeout;
>
> - /* Can deadlock when called with interrupts disabled */
> - WARN_ON(irqs_disabled());
> -
> if (unlikely(smp_ops == NULL))
> return ret;
>
> @@ -270,10 +262,19 @@ int smp_call_function_map(void (*func) (void *info), void *info, int nonatomic,
> return ret;
> }
>
> +static int __smp_call_function(void (*func)(void *info), void *info,
> + int nonatomic, int wait)
> +{
> + return smp_call_function_map(func,info,nonatomic,wait,cpu_online_map);
> +}
> +
> int smp_call_function(void (*func) (void *info), void *info, int nonatomic,
> int wait)
> {
> - return smp_call_function_map(func,info,nonatomic,wait,cpu_online_map);
> + /* Can deadlock when called with interrupts disabled */
> + WARN_ON(irqs_disabled());
> +
> + return __smp_call_function(func, info, nonatomic, wait);
> }
> EXPORT_SYMBOL(smp_call_function);
>
> @@ -283,6 +284,9 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, int
> cpumask_t map = CPU_MASK_NONE;
> int ret = 0;
>
> + /* Can deadlock when called with interrupts disabled */
> + WARN_ON(irqs_disabled());
> +
> if (!cpu_online(cpu))
> return -EINVAL;
>
> @@ -299,6 +303,11 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, int
> }
> EXPORT_SYMBOL(smp_call_function_single);
>
> +void smp_send_stop(void)
> +{
> + __smp_call_function(stop_this_cpu, NULL, 1, 0);
> +}
> +
> void smp_call_function_interrupt(void)
> {
> void (*func) (void *info);
>
Hi,
This patch solves the badness oops we get on the powerpc.
--
Thanks & Regards,
Kamalesh Babulal,
Linux Technology Center,
IBM, ISTL.
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