From: Rafael J. Wysocki rafael.j.wysocki@intel.com
[ Upstream commit 5db25c9eb893df8f6b93c1d97b8006d768e1b6f5 ]
It is incorrect to call pm_runtime_get_sync() under device_links_write_lock(), because it may end up trying to take device_links_read_lock() while resuming the target device and that will deadlock in the non-SRCU case, so avoid that by resuming the supplier device in device_link_add() before calling device_links_write_lock().
Fixes: 21d5c57b3726 ("PM / runtime: Use device links") Fixes: baa8809f6097 ("PM / runtime: Optimize the use of device links") Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/base/core.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/drivers/base/core.c b/drivers/base/core.c index 2b0a1054535ce..93c2fc58013ed 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -180,11 +180,20 @@ struct device_link *device_link_add(struct device *consumer, struct device *supplier, u32 flags) { struct device_link *link; + bool rpm_put_supplier = false;
if (!consumer || !supplier || ((flags & DL_FLAG_STATELESS) && (flags & DL_FLAG_AUTOREMOVE))) return NULL;
+ if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) { + if (pm_runtime_get_sync(supplier) < 0) { + pm_runtime_put_noidle(supplier); + return NULL; + } + rpm_put_supplier = true; + } + device_links_write_lock(); device_pm_lock();
@@ -209,13 +218,8 @@ struct device_link *device_link_add(struct device *consumer,
if (flags & DL_FLAG_PM_RUNTIME) { if (flags & DL_FLAG_RPM_ACTIVE) { - if (pm_runtime_get_sync(supplier) < 0) { - pm_runtime_put_noidle(supplier); - kfree(link); - link = NULL; - goto out; - } link->rpm_active = true; + rpm_put_supplier = false; } pm_runtime_new_link(consumer); /* @@ -286,6 +290,10 @@ struct device_link *device_link_add(struct device *consumer, out: device_pm_unlock(); device_links_write_unlock(); + + if (rpm_put_supplier) + pm_runtime_put(supplier); + return link; } EXPORT_SYMBOL_GPL(device_link_add);