On Tue, May 20, 2025 at 01:32:41PM -0300, André Almeida wrote:
> When a device get wedged, it might be caused by a guilty application.
> For userspace, knowing which task was the cause can be useful for some
> situations, like for implementing a policy, logs or for giving a chance
> for the compositor to let the user know what task caused the problem.
> This is an optional argument, when the task info is not available, the
> PID and TASK string won't appear in the event string.
>
> Sometimes just the PID isn't enough giving that the task might be already
> dead by the time userspace will try to check what was this PID's name,
> so to make the life easier also notify what's the task's name in the user
> event.
...
> -int drm_dev_wedged_event(struct drm_device *dev, unsigned long method)
> +int drm_dev_wedged_event(struct drm_device *dev, unsigned long method,
> + struct drm_wedge_task_info *info)
> {
> const char *recovery = NULL;
> unsigned int len, opt;
> - /* Event string length up to 28+ characters with available methods */
> - char event_string[32];
> - char *envp[] = { event_string, NULL };
> + char event_string[WEDGE_STR_LEN], pid_string[PID_LEN] = "",
> comm_string[TASK_COMM_LEN] = "";
> + char *envp[] = { event_string, NULL, NULL, NULL };
>
> len = scnprintf(event_string, sizeof(event_string), "%s", "WEDGED=");
>
> @@ -582,6 +586,13 @@ int drm_dev_wedged_event(struct drm_device *dev,
> unsigned long method)
> drm_info(dev, "device wedged, %s\n", method == DRM_WEDGE_RECOVERY_NONE ?
> "but recovered through reset" : "needs recovery");
>
> + if (info && ((info->comm && info->comm[0] != '\0'))) {
Thanks for adding this. Should we check if pid > 0?
Also, I was wondering what if the driver only has info on one of the
given members? Should we allow it to be flagged independently?
> + snprintf(pid_string, sizeof(pid_string), "PID=%u", info->pid);
> + snprintf(comm_string, sizeof(comm_string), "TASK=%s",
> info->comm);
> + envp[1] = pid_string;
> + envp[2] = comm_string;
> + }
> +
> return kobject_uevent_env(&dev->primary->kdev->kobj, KOBJ_CHANGE, envp);
> }
> EXPORT_SYMBOL(drm_dev_wedged_event);
...
> diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h
> index e2f894f1b90a..c13fe85210f2 100644
> --- a/include/drm/drm_device.h
> +++ b/include/drm/drm_device.h
> @@ -30,6 +30,14 @@ struct pci_controller;
> #define DRM_WEDGE_RECOVERY_REBIND BIT(1) /* unbind + bind driver */
> #define DRM_WEDGE_RECOVERY_BUS_RESET BIT(2) /* unbind + reset bus device +
> bind */
>
> +/**
> + * struct drm_wedge_task_info - information about the guilty app of a wedge
> dev
s/app/task, missed an instance ;)
> + */
> +struct drm_wedge_task_info {
> + pid_t pid;
> + char *comm;
> +};
Raag
