From: Madhuparna Bhowmik <[email protected]>
This patch passes the cond argument to list_for_each_entry_rcu()
to fix the following false-positive lockdep warnings:
(with CONFIG_PROVE_RCU_LIST = y)
[ 330.302784] =============================
[ 330.302789] WARNING: suspicious RCU usage
[ 330.302796] 5.6.0-rc1+ #5 Not tainted
[ 330.302801] -----------------------------
[ 330.302808] drivers/base/power/main.c:326 RCU-list traversed in non-reader section!!
[ 330.303303] =============================
[ 330.303307] WARNING: suspicious RCU usage
[ 330.303311] 5.6.0-rc1+ #5 Not tainted
[ 330.303315] -----------------------------
[ 330.303319] drivers/base/power/main.c:1698 RCU-list traversed in non-reader section!!
[ 331.934969] =============================
[ 331.934971] WARNING: suspicious RCU usage
[ 331.934973] 5.6.0-rc1+ #5 Not tainted
[ 331.934975] -----------------------------
[ 331.934977] drivers/base/power/main.c:1238 RCU-list traversed in non-reader section!!
[ 332.467772] WARNING: suspicious RCU usage
[ 332.467775] 5.6.0-rc1+ #5 Not tainted
[ 332.467775] -----------------------------
[ 332.467778] drivers/base/power/main.c:269 RCU-list traversed in non-reader section!!
Signed-off-by: Madhuparna Bhowmik <[email protected]>
---
drivers/base/power/main.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 0e99a760aebd..6d1dee7051eb 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -40,6 +40,10 @@
typedef int (*pm_callback_t)(struct device *);
+#define list_for_each_entry_rcu_locked(pos, head, member) \
+ list_for_each_entry_rcu(pos, head, member, \
+ device_links_read_lock_held())
+
/*
* The entries in the dpm_list list are in a depth first order, simply
* because children are guaranteed to be discovered after parents, and
@@ -266,7 +270,7 @@ static void dpm_wait_for_suppliers(struct device *dev, bool async)
* callbacks freeing the link objects for the links in the list we're
* walking.
*/
- list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
+ list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node)
if (READ_ONCE(link->status) != DL_STATE_DORMANT)
dpm_wait(link->supplier, async);
@@ -323,7 +327,7 @@ static void dpm_wait_for_consumers(struct device *dev, bool async)
* continue instead of trying to continue in parallel with its
* unregistration).
*/
- list_for_each_entry_rcu(link, &dev->links.consumers, s_node)
+ list_for_each_entry_rcu_locked(link, &dev->links.consumers, s_node)
if (READ_ONCE(link->status) != DL_STATE_DORMANT)
dpm_wait(link->consumer, async);
@@ -1235,7 +1239,7 @@ static void dpm_superior_set_must_resume(struct device *dev)
idx = device_links_read_lock();
- list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
+ list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node)
link->supplier->power.must_resume = true;
device_links_read_unlock(idx);
@@ -1695,7 +1699,7 @@ static void dpm_clear_superiors_direct_complete(struct device *dev)
idx = device_links_read_lock();
- list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) {
+ list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node) {
spin_lock_irq(&link->supplier->power.lock);
link->supplier->power.direct_complete = false;
spin_unlock_irq(&link->supplier->power.lock);
--
2.17.1
On Tuesday, March 3, 2020 8:41:30 PM CET [email protected] wrote:
> From: Madhuparna Bhowmik <[email protected]>
>
> This patch passes the cond argument to list_for_each_entry_rcu()
> to fix the following false-positive lockdep warnings:
> (with CONFIG_PROVE_RCU_LIST = y)
>
> [ 330.302784] =============================
> [ 330.302789] WARNING: suspicious RCU usage
> [ 330.302796] 5.6.0-rc1+ #5 Not tainted
> [ 330.302801] -----------------------------
> [ 330.302808] drivers/base/power/main.c:326 RCU-list traversed in non-reader section!!
>
> [ 330.303303] =============================
> [ 330.303307] WARNING: suspicious RCU usage
> [ 330.303311] 5.6.0-rc1+ #5 Not tainted
> [ 330.303315] -----------------------------
> [ 330.303319] drivers/base/power/main.c:1698 RCU-list traversed in non-reader section!!
>
> [ 331.934969] =============================
> [ 331.934971] WARNING: suspicious RCU usage
> [ 331.934973] 5.6.0-rc1+ #5 Not tainted
> [ 331.934975] -----------------------------
> [ 331.934977] drivers/base/power/main.c:1238 RCU-list traversed in non-reader section!!
>
> [ 332.467772] WARNING: suspicious RCU usage
> [ 332.467775] 5.6.0-rc1+ #5 Not tainted
> [ 332.467775] -----------------------------
> [ 332.467778] drivers/base/power/main.c:269 RCU-list traversed in non-reader section!!
>
> Signed-off-by: Madhuparna Bhowmik <[email protected]>
> ---
> drivers/base/power/main.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index 0e99a760aebd..6d1dee7051eb 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -40,6 +40,10 @@
>
> typedef int (*pm_callback_t)(struct device *);
>
> +#define list_for_each_entry_rcu_locked(pos, head, member) \
> + list_for_each_entry_rcu(pos, head, member, \
> + device_links_read_lock_held())
> +
> /*
> * The entries in the dpm_list list are in a depth first order, simply
> * because children are guaranteed to be discovered after parents, and
> @@ -266,7 +270,7 @@ static void dpm_wait_for_suppliers(struct device *dev, bool async)
> * callbacks freeing the link objects for the links in the list we're
> * walking.
> */
> - list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
> + list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node)
> if (READ_ONCE(link->status) != DL_STATE_DORMANT)
> dpm_wait(link->supplier, async);
>
> @@ -323,7 +327,7 @@ static void dpm_wait_for_consumers(struct device *dev, bool async)
> * continue instead of trying to continue in parallel with its
> * unregistration).
> */
> - list_for_each_entry_rcu(link, &dev->links.consumers, s_node)
> + list_for_each_entry_rcu_locked(link, &dev->links.consumers, s_node)
> if (READ_ONCE(link->status) != DL_STATE_DORMANT)
> dpm_wait(link->consumer, async);
>
> @@ -1235,7 +1239,7 @@ static void dpm_superior_set_must_resume(struct device *dev)
>
> idx = device_links_read_lock();
>
> - list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
> + list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node)
> link->supplier->power.must_resume = true;
>
> device_links_read_unlock(idx);
> @@ -1695,7 +1699,7 @@ static void dpm_clear_superiors_direct_complete(struct device *dev)
>
> idx = device_links_read_lock();
>
> - list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) {
> + list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node) {
> spin_lock_irq(&link->supplier->power.lock);
> link->supplier->power.direct_complete = false;
> spin_unlock_irq(&link->supplier->power.lock);
>
Applied along with the [2/2] (with updated changelogs) as 5.7 material.
Thanks!