[PATCH v2 2/2] powerpc: Do not assign thread.tidr if already assigned

[Andrew Donnellan]

On 24/11/17 19:33, Vaibhav Jain wrote:
> If set_thread_tidr() is called twice for same task_struct then it will
> allocate a new tidr value to it leaving the previous value still
> dangling in the vas_thread_ida table.
> 
> To fix this the patch changes set_thread_tidr() to check if a tidr
> value is already assigned to the task_struct and if yes then returns
> the existing value from function instead of allocating a new one.
> 
> Fixes: ec233ede4c86("powerpc: Add support for setting SPRN_TIDR")
> Signed-off-by: Vaibhav Jain <vaibhav at linux.vnet.ibm.com>

Reviewed-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>

> ---
> v2 ->	Fix minor spell errors in patch description
> ---
>   arch/powerpc/kernel/process.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
> index 5d8176c7c2d8..9a72282b022d 100644
> --- a/arch/powerpc/kernel/process.c
> +++ b/arch/powerpc/kernel/process.c
> @@ -1577,6 +1577,9 @@ int set_thread_tidr(struct task_struct *t)
>   	if (t != current)
>   		return -EINVAL;
> 
> +	if (t->thread.tidr)
> +		return t->thread.tidr;
> +
>   	rc = assign_thread_tidr();
>   	if (rc > 0) {
>   		t->thread.tidr = rc;
> 

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan at au1.ibm.com  IBM Australia Limited