On Friday, January 29, 2016 04:33:39 PM Saravana Kannan wrote: > On 01/12/2016 02:20 AM, Viresh Kumar wrote: > > On 11-01-16, 17:35, Juri Lelli wrote: > >> __cpufreq_governor works on policy, so policy->rwsem has to be held. > >> Add assertion for such condition. > >> > >> Cc: "Rafael J. Wysocki" <[email protected]> > >> Cc: Viresh Kumar <[email protected]> > >> Signed-off-by: Juri Lelli <[email protected]> > >> --- > >> drivers/cpufreq/cpufreq.c | 3 +++ > >> 1 file changed, 3 insertions(+) > >> > >> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > >> index f1f9fbc..e7fc5c9 100644 > >> --- a/drivers/cpufreq/cpufreq.c > >> +++ b/drivers/cpufreq/cpufreq.c > >> @@ -1950,6 +1950,9 @@ static int __cpufreq_governor(struct cpufreq_policy > >> *policy, > >> /* Don't start any governor operations if we are entering suspend */ > >> if (cpufreq_suspended) > >> return 0; > >> + > >> + lockdep_assert_held(&policy->rwsem); > >> + > > > > We had an ABBA problem with the EXIT governor callback and so this > > rwsem is dropped just before that from set_policy().. > > > > commit 955ef4833574 ("cpufreq: Drop rwsem lock around > > CPUFREQ_GOV_POLICY_EXIT") > > > > AFAIR, the ABBA issue was between the sysfs lock and the policy lock. > The fix for that issue should not be dropping the lock around > POLICY_EXIT.
Right. Dropping the lock is a mistake (which I overlooked, sadly). Thanks, Rafael
