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| author | Alexander Shishkin <alexander.shishkin@linux.intel.com> | 2016-06-30 11:51:44 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-08-10 12:54:50 +0200 |
| commit | 900ac92c5514dd8c63a8f3c91942dcb4cc6bd0f3 (patch) | |
| tree | aae77ddbcb6a6333171de38addf2d46f23c88e64 | |
| parent | df1abbea005a621a497fc9def893ed2c6cba4d94 (diff) | |
| download | lwn-900ac92c5514dd8c63a8f3c91942dcb4cc6bd0f3.tar.gz lwn-900ac92c5514dd8c63a8f3c91942dcb4cc6bd0f3.zip | |
intel_th: Fix a deadlock in modprobing
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 <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/hwtracing/intel_th/core.c | 35 | ||||
| -rw-r--r-- | drivers/hwtracing/intel_th/intel_th.h | 3 |
2 files changed, 37 insertions, 1 deletions
diff --git a/drivers/hwtracing/intel_th/core.c b/drivers/hwtracing/intel_th/core.c index 4272f2ce5f6e..dca16540e7fd 100644 --- a/drivers/hwtracing/intel_th/core.c +++ b/drivers/hwtracing/intel_th/core.c @@ -440,6 +440,38 @@ 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) { @@ -510,7 +542,7 @@ static int intel_th_populate(struct intel_th *th, struct resource *devres, /* 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++; } @@ -627,6 +659,7 @@ 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]); diff --git a/drivers/hwtracing/intel_th/intel_th.h b/drivers/hwtracing/intel_th/intel_th.h index eedd09332db6..72cd3c6018e1 100644 --- a/drivers/hwtracing/intel_th/intel_th.h +++ b/drivers/hwtracing/intel_th/intel_th.h @@ -199,6 +199,9 @@ 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 |