Re: tip: origin tree boot crash

Steffen Klassert
2010-03-01T15:18:25Z

Hi.

On Mon, Mar 01, 2010 at 08:50:24AM +0100, Ingo Molnar wrote:
>
> Hi,
>
> * Herbert Xu <herbert@gondor.apana.org.au> wrote:
>
> > crypto: pcrypt - Add pcrypt crypto parallelization wrapper
>
> -tip testing started triggering the following frequent boot crash yesterday,
> on 64-bit x86:
>
> | calling pcrypt_init+0x0/0xee @ 1
> | BUG: unable to handle kernel NULL pointer dereference at (null)
> | IP: [<ffffffff8126550b>] memcpy+0xb/0xb0
> | Call Trace:
> | [<ffffffff810c2f38>] ? padata_alloc+0x98/0x150
> | [<ffffffff82158c51>] ? pcrypt_init+0x0/0xee
> | [<ffffffff82158ccc>] pcrypt_init+0x7b/0xee
>

Ugh, it seems that I forgot to allocate one of the cpumasks. Looking at the
configs of my test systems I noticed, that CONFIG_CPUMASK_OFFSTACK was
not set on all the configs, so I did not notice it.

The patch below fixes the boot crash if CONFIG_CPUMASK_OFFSTACK is
enabled on my test systems. Does the patch fix it for you too?

Thanks,

Steffen

Subject: [PATCH] padata: allocate the cpumask for the padata instance

The cpumask of the padata instance was used without allocated.
This caused boot crashes if CONFIG_CPUMASK_OFFSTACK is enabled.
This patch fixes this by doing proper allocation for this cpumask.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
kernel/padata.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/kernel/padata.c b/kernel/padata.c
index 6f9bcb8..93caf65 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -642,6 +642,9 @@ struct padata_instance *padata_alloc(const struct cpumask *cpumask,
if (!pd)
goto err_free_inst;

+ if (!alloc_cpumask_var(&pinst->cpumask, GFP_KERNEL))
+ goto err_free_pd;
+
rcu_assign_pointer(pinst->pd, pd);

pinst->wq = wq;
@@ -654,12 +657,14 @@ struct padata_instance *padata_alloc(const struct cpumask *cpumask,
pinst->cpu_notifier.priority = 0;
err = register_hotcpu_notifier(&pinst->cpu_notifier);
if (err)
- goto err_free_pd;
+ goto err_free_cpumask;

mutex_init(&pinst->lock);

return pinst;

+err_free_cpumask:
+ free_cpumask_var(pinst->cpumask);
err_free_pd:
padata_free_pd(pd);
err_free_inst:
@@ -685,6 +690,7 @@ void padata_free(struct padata_instance *pinst)

unregister_hotcpu_notifier(&pinst->cpu_notifier);
padata_free_pd(pinst->pd);
+ free_cpumask_var(pinst->cpumask);
kfree(pinst);
}
EXPORT_SYMBOL(padata_free);
--
1.5.6.5