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@xxxxxx> Acked-by: Arnaud Pouliquen <arnaud.pouliquen@xxxxxx> --- v2: rebased version, no changes v1: https://patchwork.kernel.org/project/linux-remoteproc/patch/20180915003725.17549-2-s-anna@xxxxxx/ 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 d1cf7bf277c4..bd2950a246c9 100644 --- a/drivers/remoteproc/remoteproc_sysfs.c +++ b/drivers/remoteproc/remoteproc_sysfs.c @@ -3,6 +3,7 @@ * Remote Processor Framework */ +#include <linux/module.h> #include <linux/remoteproc.h> #include <linux/slab.h> @@ -228,14 +229,27 @@ 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; -- 2.28.0
