Messages in this thread | | | Date | Sun, 01 Mar 2020 15:53:07 -0500 | Subject | Re: [PATCH 1/2] drivers: base: power: main: Use built-in RCU list checking | From | joel@joelfern ... |
| |
On March 1, 2020 3:12:53 PM EST, "Rafael J. Wysocki" <rafael@kernel.org> wrote: >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?
You have to enable lockdep in your config. Does your setup have that?
Thanks,
- Joel
> >> >> 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 >>
-- Sent from my Android device with K-9 Mail. Please excuse my brevity.
| |