lkml.org 
[lkml]   [2020]   [Mar]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH 1/2] drivers: base: power: main: Use built-in RCU list checking
On Fri, Feb 28, 2020 at 6:47 PM <madhuparnabhowmik10@gmail.com> wrote:
>
> From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
>
> This patch passes the cond argument to list_for_each_entry_rcu()
> to fix the following false-positive lockdep warnings:
>
> [ 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!!

I don't see these warnings in the kernels run locally here.

What do you do to get them?

Joel, any comments here?

>
> Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
> ---
> 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..742c05f3c1e7 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -266,7 +266,8 @@ 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(link, &dev->links.suppliers, c_node,
> + device_links_read_lock_held())
> if (READ_ONCE(link->status) != DL_STATE_DORMANT)
> dpm_wait(link->supplier, async);
>
> @@ -323,7 +324,8 @@ 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(link, &dev->links.consumers, s_node,
> + device_links_read_lock_held())
> if (READ_ONCE(link->status) != DL_STATE_DORMANT)
> dpm_wait(link->consumer, async);
>
> @@ -1235,7 +1237,8 @@ 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(link, &dev->links.suppliers, c_node,
> + device_links_read_lock_held())
> link->supplier->power.must_resume = true;
>
> device_links_read_unlock(idx);
> @@ -1695,7 +1698,8 @@ 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(link, &dev->links.suppliers, c_node,
> + device_links_read_lock_held()) {
> spin_lock_irq(&link->supplier->power.lock);
> link->supplier->power.direct_complete = false;
> spin_unlock_irq(&link->supplier->power.lock);
> --
> 2.17.1
>

\
 
 \ /
  Last update: 2020-03-01 21:13    [W:0.070 / U:9.912 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site