From: Nishanth Menon Date: Fri, 18 Jan 2013 19:52:33 +0000 (+0000) Subject: cpufreq: cpufreq-cpu0: use RCU locks around usage of OPP X-Git-Tag: firefly_0821_release~3680^2~1205^2~4 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=78e8eb8feab7d85f4cc215afe1457a228bf4eed9;p=firefly-linux-kernel-4.4.55.git cpufreq: cpufreq-cpu0: use RCU locks around usage of OPP OPP pointer is RCU protected, hence after finding it, de-reference also should be protected with the same RCU context else the OPP pointer may become invalid. Reported-by: Jack Mitchell Tested-by: Alexander Holler Tested-by: Jack Mitchell Acked-by: Alexander Holler Signed-off-by: Nishanth Menon Signed-off-by: Rafael J. Wysocki --- diff --git a/drivers/cpufreq/cpufreq-cpu0.c b/drivers/cpufreq/cpufreq-cpu0.c index 52bf36d599f5..debc5a7c8db6 100644 --- a/drivers/cpufreq/cpufreq-cpu0.c +++ b/drivers/cpufreq/cpufreq-cpu0.c @@ -71,12 +71,15 @@ static int cpu0_set_target(struct cpufreq_policy *policy, } if (cpu_reg) { + rcu_read_lock(); opp = opp_find_freq_ceil(cpu_dev, &freq_Hz); if (IS_ERR(opp)) { + rcu_read_unlock(); pr_err("failed to find OPP for %ld\n", freq_Hz); return PTR_ERR(opp); } volt = opp_get_voltage(opp); + rcu_read_unlock(); tol = volt * voltage_tolerance / 100; volt_old = regulator_get_voltage(cpu_reg); } @@ -236,12 +239,14 @@ static int cpu0_cpufreq_driver_init(void) */ for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) ; + rcu_read_lock(); opp = opp_find_freq_exact(cpu_dev, freq_table[0].frequency * 1000, true); min_uV = opp_get_voltage(opp); opp = opp_find_freq_exact(cpu_dev, freq_table[i-1].frequency * 1000, true); max_uV = opp_get_voltage(opp); + rcu_read_unlock(); ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV); if (ret > 0) transition_latency += ret * 1000;