Re: [PATCH 1/5] remoteproc: Fix unbalanced boot with sysfs for no auto-boot rprocs

Arnaud Pouliquen
2018-10-02T09:27:27Z

Hi Suman,

On 09/15/2018 02:37 AM, Suman Anna wrote:
> The remoteproc core performs automatic boot and shutdown of a remote
> processor during rproc_add() and rproc_del() for remote processors
> supporting 'auto-boot'. The remoteproc devices not using 'auto-boot'
> require either a remoteproc client driver or a userspace client to
> use the sysfs 'state' variable to perform the boot and shutdown. The
> in-kernel client drivers hold the corresponding remoteproc driver
> module's reference count when they acquire a rproc handle through
> the rproc_get_by_phandle() API, but there is no such support for
> userspace applications performing the boot through sysfs interface.
>
> The shutdown of a remoteproc upon removing a remoteproc platform
> driver is automatic only with 'auto-boot' and this can cause a
> remoteproc with no auto-boot to stay powered on and never freed
> up if booted using the sysfs interface without a matching stop,
> and when the remoteproc driver module is removed or unbound from
> the device. This will result in a memory leak as well as the
> corresponding remoteproc ida being never deallocated. Fix this
> by holding a module reference count for the remoteproc's driver
> during a sysfs 'start' and releasing it during the sysfs 'stop'
> operation.
>
> Signed-off-by: Suman Anna <s-anna@ti.com>
> ---
> drivers/remoteproc/remoteproc_sysfs.c | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c
> index 47be411400e5..2142b3ea726e 100644
> --- a/drivers/remoteproc/remoteproc_sysfs.c
> +++ b/drivers/remoteproc/remoteproc_sysfs.c
> @@ -11,6 +11,7 @@
> * GNU General Public License for more details.
> */
>
> +#include <linux/module.h>
> #include <linux/remoteproc.h>
>
> #include "remoteproc_internal.h"
> @@ -100,14 +101,27 @@ static ssize_t state_store(struct device *dev,
> if (rproc->state == RPROC_RUNNING)
> return -EBUSY;
>
> + /*
> + * prevent underlying implementation from being removed
> + * when remoteproc does not support auto-boot
> + */
> + if (!rproc->auto_boot &&
> + !try_module_get(dev->parent->driver->owner))
> + return -EINVAL;
> +
> ret = rproc_boot(rproc);
> - if (ret)
> + if (ret) {
> dev_err(&rproc->dev, "Boot failed: %d\n", ret);
> + if (!rproc->auto_boot)
> + module_put(dev->parent->driver->owner);
> + }
> } else if (sysfs_streq(buf, "stop")) {
> if (rproc->state != RPROC_RUNNING)
> return -EINVAL;
>
> rproc_shutdown(rproc);
> + if (!rproc->auto_boot)
> + module_put(dev->parent->driver->owner);
> } else {
> dev_err(&rproc->dev, "Unrecognised option: %s\n", buf);
> ret = -EINVAL;
>
Looks good for me, i tested on ST platform and did not detect any
regression.
Acked-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>

Regards
Arnaud