diff options
| -rw-r--r-- | arch/x86/kernel/ds.c | 26 |
1 files changed, 21 insertions, 5 deletions
diff --git a/arch/x86/kernel/ds.c b/arch/x86/kernel/ds.c index ac1d5b0586b..d1a121443bd 100644 --- a/arch/x86/kernel/ds.c +++ b/arch/x86/kernel/ds.c @@ -236,17 +236,33 @@ static inline struct ds_context *ds_alloc_context(struct task_struct *task) struct ds_context *context = *p_context; if (!context) { + spin_unlock(&ds_lock); + context = kzalloc(sizeof(*context), GFP_KERNEL); - if (!context) + if (!context) { + spin_lock(&ds_lock); return NULL; + } context->ds = kzalloc(ds_cfg.sizeof_ds, GFP_KERNEL); if (!context->ds) { kfree(context); + spin_lock(&ds_lock); return NULL; } + spin_lock(&ds_lock); + /* + * Check for race - another CPU could have allocated + * it meanwhile: + */ + if (*p_context) { + kfree(context->ds); + kfree(context); + return *p_context; + } + *p_context = context; context->this = p_context; @@ -384,15 +400,15 @@ static int ds_request(struct task_struct *task, void *base, size_t size, spin_lock(&ds_lock); - error = -EPERM; - if (!check_tracer(task)) - goto out_unlock; - error = -ENOMEM; context = ds_alloc_context(task); if (!context) goto out_unlock; + error = -EPERM; + if (!check_tracer(task)) + goto out_unlock; + error = -EALREADY; if (context->owner[qual] == current) goto out_unlock; |