[linux-pm] [PATCH] power: opp: Fix rcu_dereference_check() without protection!
Santosh Shilimkar
santosh.shilimkar at ti.com
Tue Jun 14 06:03:20 PDT 2011
With RCU debug options enabled, below warning is observed.
===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
drivers/base/power/opp.c:151 invoked rcu_dereference_check() without protection!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 1
no locks held by swapper/1.
...
---------------------------------------------------
Fix the same by protecting it with rcu_read lock.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar at ti.com>
Cc: Rafael J. Wysocki <rjw at sisk.pl>
Cc: Nishanth Menon <nm at ti.com>
Cc: Kevin Hilman <khilman at deeprootsystems.com>
---
drivers/base/power/opp.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 56a6899..cbed5e1 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -148,7 +148,9 @@ unsigned long opp_get_voltage(struct opp *opp)
struct opp *tmp_opp;
unsigned long v = 0;
+ rcu_read_lock();
tmp_opp = rcu_dereference(opp);
+ rcu_read_unlock();
if (unlikely(IS_ERR_OR_NULL(tmp_opp)) || !tmp_opp->available)
pr_err("%s: Invalid parameters\n", __func__);
else
--
1.6.0.4
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