4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Alexander Shishkin <[email protected]> commit a36aa80f3cb2540fb1dbad6240852de4365a2e82 upstream. Driver initialization tries to request a hub (GTH) driver module from its probe callback, resulting in a deadlock. This patch solves the problem by adding a deferred work for requesting the hub module. Signed-off-by: Alexander Shishkin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/hwtracing/intel_th/core.c | 35 +++++++++++++++++++++++++++++++++- drivers/hwtracing/intel_th/intel_th.h | 3 ++ 2 files changed, 37 insertions(+), 1 deletion(-) --- a/drivers/hwtracing/intel_th/core.c +++ b/drivers/hwtracing/intel_th/core.c @@ -419,6 +419,38 @@ static struct intel_th_subdevice { }, }; +#ifdef CONFIG_MODULES +static void __intel_th_request_hub_module(struct work_struct *work) +{ + struct intel_th *th = container_of(work, struct intel_th, + request_module_work); + + request_module("intel_th_%s", th->hub->name); +} + +static int intel_th_request_hub_module(struct intel_th *th) +{ + INIT_WORK(&th->request_module_work, __intel_th_request_hub_module); + schedule_work(&th->request_module_work); + + return 0; +} + +static void intel_th_request_hub_module_flush(struct intel_th *th) +{ + flush_work(&th->request_module_work); +} +#else +static inline int intel_th_request_hub_module(struct intel_th *th) +{ + return -EINVAL; +} + +static inline void intel_th_request_hub_module_flush(struct intel_th *th) +{ +} +#endif /* CONFIG_MODULES */ + static int intel_th_populate(struct intel_th *th, struct resource *devres, unsigned int ndevres, int irq) { @@ -488,7 +520,7 @@ static int intel_th_populate(struct inte /* need switch driver to be loaded to enumerate the rest */ if (subdev->type == INTEL_TH_SWITCH && !req) { th->hub = thdev; - err = request_module("intel_th_%s", subdev->name); + err = intel_th_request_hub_module(th); if (!err) req++; } @@ -603,6 +635,7 @@ void intel_th_free(struct intel_th *th) { int i; + intel_th_request_hub_module_flush(th); for (i = 0; i < TH_SUBDEVICE_MAX; i++) if (th->thdev[i] != th->hub) intel_th_device_remove(th->thdev[i]); --- a/drivers/hwtracing/intel_th/intel_th.h +++ b/drivers/hwtracing/intel_th/intel_th.h @@ -197,6 +197,9 @@ struct intel_th { int id; int major; +#ifdef CONFIG_MODULES + struct work_struct request_module_work; +#endif /* CONFIG_MODULES */ #ifdef CONFIG_INTEL_TH_DEBUG struct dentry *dbg; #endif
