On 2019/5/31 17:29, Kefeng Wang wrote:
> There is a deadlock issue in pcrypt_init_padata(),
>
> pcrypt_init_padata()
> cpus_read_lock()
> padata_free()
> padata_sysfs_release()
> cpus_read_lock()
>
> Narrow rcu_read_lock/unlock() and move put_online_cpus()
> before padata_free() to fix it.
>
> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
> ---
> crypto/pcrypt.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/crypto/pcrypt.c b/crypto/pcrypt.c
> index 0e9ce329fd47..662228b48b70 100644
> --- a/crypto/pcrypt.c
> +++ b/crypto/pcrypt.c
> @@ -407,13 +407,14 @@ static int pcrypt_init_padata(struct padata_pcrypt *pcrypt,
> int ret = -ENOMEM;
> struct pcrypt_cpumask *mask;
>
> - get_online_cpus();
>
> pcrypt->wq = alloc_workqueue("%s", WQ_MEM_RECLAIM | WQ_CPU_INTENSIVE,
> 1, name);
> if (!pcrypt->wq)
> goto err;
>
> + get_online_cpus();
> +
> pcrypt->pinst = padata_alloc_possible(pcrypt->wq);
> if (!pcrypt->pinst)
Oh, forget to add put_online_cpus in this error path, will resend v2 if there is no comment.
> goto err_destroy_workqueue;
> @@ -448,12 +449,11 @@ static int pcrypt_init_padata(struct padata_pcrypt *pcrypt,
> free_cpumask_var(mask->mask);
> kfree(mask);
> err_free_padata:
> + put_online_cpus();
> padata_free(pcrypt->pinst);
> err_destroy_workqueue:
> destroy_workqueue(pcrypt->wq);
> err:
> - put_online_cpus();
> -
> return ret;
> }
>
