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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-04-28 10:32:58 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-04-28 10:32:58 +0200
commit615dca38c2eae55aff80050275931c87a812b48c (patch)
tree8674a3a3f66a39bf7c7f2ab733a757e624bd99ec /drivers/cpufreq/cpufreq.c
parent3baea29dc0a7b561170d7082f831a613ae6aa56e (diff)
parentb4432656b36e5cc1d50a1f2dc15357543add530e (diff)
Merge 6.15-rc4 into usb-next
We need the USB fixes in here as well, and this resolves the following merge conflicts that were reported in linux-next: drivers/usb/chipidea/ci_hdrc_imx.c drivers/usb/host/xhci.h Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
-rw-r--r--drivers/cpufreq/cpufreq.c32
1 files changed, 25 insertions, 7 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 3841c9da6cac..acf19b0042bb 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -540,8 +540,6 @@ static unsigned int __resolve_freq(struct cpufreq_policy *policy,
{
unsigned int idx;
- target_freq = clamp_val(target_freq, policy->min, policy->max);
-
if (!policy->freq_table)
return target_freq;
@@ -565,7 +563,22 @@ static unsigned int __resolve_freq(struct cpufreq_policy *policy,
unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
unsigned int target_freq)
{
- return __resolve_freq(policy, target_freq, CPUFREQ_RELATION_LE);
+ unsigned int min = READ_ONCE(policy->min);
+ unsigned int max = READ_ONCE(policy->max);
+
+ /*
+ * If this function runs in parallel with cpufreq_set_policy(), it may
+ * read policy->min before the update and policy->max after the update
+ * or the other way around, so there is no ordering guarantee.
+ *
+ * Resolve this by always honoring the max (in case it comes from
+ * thermal throttling or similar).
+ */
+ if (unlikely(min > max))
+ min = max;
+
+ return __resolve_freq(policy, clamp_val(target_freq, min, max),
+ CPUFREQ_RELATION_LE);
}
EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq);
@@ -2384,6 +2397,7 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
if (cpufreq_disabled())
return -ENODEV;
+ target_freq = clamp_val(target_freq, policy->min, policy->max);
target_freq = __resolve_freq(policy, target_freq, relation);
pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
@@ -2708,11 +2722,15 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,
* Resolve policy min/max to available frequencies. It ensures
* no frequency resolution will neither overshoot the requested maximum
* nor undershoot the requested minimum.
+ *
+ * Avoid storing intermediate values in policy->max or policy->min and
+ * compiler optimizations around them because they may be accessed
+ * concurrently by cpufreq_driver_resolve_freq() during the update.
*/
- policy->min = new_data.min;
- policy->max = new_data.max;
- policy->min = __resolve_freq(policy, policy->min, CPUFREQ_RELATION_L);
- policy->max = __resolve_freq(policy, policy->max, CPUFREQ_RELATION_H);
+ WRITE_ONCE(policy->max, __resolve_freq(policy, new_data.max, CPUFREQ_RELATION_H));
+ new_data.min = __resolve_freq(policy, new_data.min, CPUFREQ_RELATION_L);
+ WRITE_ONCE(policy->min, new_data.min > policy->max ? policy->max : new_data.min);
+
trace_cpu_frequency_limits(policy);
cpufreq_update_pressure(policy);