Messages in this thread Patch in this message | | | Date | Thu, 23 Oct 2008 21:47:20 -0700 | From | Hiroshi Shimamoto <> | Subject | [PATCH -tip/cpus4096-v2] cpumask: fix cpumask of call_function_data |
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From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
The following assignment in smp_call_function_many() may cause unexpected behavior, when !CPUMASK_OFFSTACK. data->cpumask = allbutself;
Because it copys pointer of stack and the value will be modified after exit from smp_call_function_many().
The type of cpumask field of call_function_data structure should be cpumask_var_t and an operation to assign is needed.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> --- include/linux/cpumask.h | 9 +++++++++ kernel/smp.c | 4 ++-- 2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index d1f22ee..7bfc0f1 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -511,6 +511,10 @@ typedef struct cpumask *cpumask_var_t; bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags); void free_cpumask_var(cpumask_var_t mask); +static inline void assign_cpumask_var(cpumask_var_t *dst, cpumask_var_t src) +{ + *dst = src; +} #else typedef struct cpumask cpumask_var_t[1]; @@ -524,6 +528,11 @@ static inline void free_cpumask_var(cpumask_var_t mask) { } +static inline void assign_cpumask_var(cpumask_var_t *dst, cpumask_var_t src) +{ + (*dst)[0] = src[0]; +} + #endif /* CONFIG_CPUMASK_OFFSTACK */ /* diff --git a/kernel/smp.c b/kernel/smp.c index dccbb42..da98191 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -24,7 +24,7 @@ struct call_function_data { struct call_single_data csd; spinlock_t lock; unsigned int refs; - struct cpumask *cpumask; + cpumask_var_t cpumask; struct rcu_head rcu_head; }; @@ -370,7 +370,7 @@ void smp_call_function_many(const struct cpumask *mask, data->csd.func = func; data->csd.info = info; data->refs = num_cpus; - data->cpumask = allbutself; + assign_cpumask_var(&data->cpumask, allbutself); spin_lock_irqsave(&call_function_lock, flags); list_add_tail_rcu(&data->csd.list, &call_function_queue); -- 1.5.6
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