From b99f20c45949968c1f40b05712d515421e18b426 Mon Sep 17 00:00:00 2001 From: Leonard Crestez Date: Tue, 24 Sep 2019 10:52:23 +0300 Subject: PM / devfreq: Lock devfreq in trans_stat_show commit 2abb0d5268ae7b5ddf82099b1f8d5aa8414637d4 upstream. There is no locking in this sysfs show function so stats printing can race with a devfreq_update_status called as part of freq switching or with initialization. Also add an assert in devfreq_update_status to make it clear that lock must be held by caller. Fixes: 39688ce6facd ("PM / devfreq: account suspend/resume for stats") Cc: stable@vger.kernel.org Signed-off-by: Leonard Crestez Reviewed-by: Matthias Kaehlcke Reviewed-by: Chanwoo Choi Signed-off-by: Chanwoo Choi Signed-off-by: Greg Kroah-Hartman --- drivers/devfreq/devfreq.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'drivers/devfreq/devfreq.c') diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index db70cee71caa..df62e38de5f5 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -135,6 +135,7 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) int lev, prev_lev, ret = 0; unsigned long cur_time; + lockdep_assert_held(&devfreq->lock); cur_time = jiffies; /* Immediately exit if previous_freq is not initialized yet. */ @@ -1170,12 +1171,17 @@ static ssize_t trans_stat_show(struct device *dev, int i, j; unsigned int max_state = devfreq->profile->max_state; - if (!devfreq->stop_polling && - devfreq_update_status(devfreq, devfreq->previous_freq)) - return 0; if (max_state == 0) return sprintf(buf, "Not Supported.\n"); + mutex_lock(&devfreq->lock); + if (!devfreq->stop_polling && + devfreq_update_status(devfreq, devfreq->previous_freq)) { + mutex_unlock(&devfreq->lock); + return 0; + } + mutex_unlock(&devfreq->lock); + len = sprintf(buf, " From : To\n"); len += sprintf(buf + len, " :"); for (i = 0; i < max_state; i++) -- cgit v1.2.3 From ce13d56c68f431e2be4833b4733fad349f43f4bd Mon Sep 17 00:00:00 2001 From: Leonard Crestez Date: Thu, 14 Nov 2019 01:21:31 +0200 Subject: PM / devfreq: Don't fail devfreq_dev_release if not in list [ Upstream commit 42a6b25e67df6ee6675e8d1eaf18065bd73328ba ] Right now devfreq_dev_release will print a warning and abort the rest of the cleanup if the devfreq instance is not part of the global devfreq_list. But this is a valid scenario, for example it can happen if the governor can't be found or on any other init error that happens after device_register. Initialize devfreq->node to an empty list head in devfreq_add_device so that list_del becomes a safe noop inside devfreq_dev_release and we can continue the rest of the cleanup. Signed-off-by: Leonard Crestez Reviewed-by: Matthias Kaehlcke Reviewed-by: Chanwoo Choi Signed-off-by: Chanwoo Choi Signed-off-by: Sasha Levin --- drivers/devfreq/devfreq.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) (limited to 'drivers/devfreq/devfreq.c') diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index df62e38de5f5..fb696957eb21 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -482,11 +482,6 @@ static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type, static void _remove_devfreq(struct devfreq *devfreq) { mutex_lock(&devfreq_list_lock); - if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) { - mutex_unlock(&devfreq_list_lock); - dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n"); - return; - } list_del(&devfreq->node); mutex_unlock(&devfreq_list_lock); @@ -558,6 +553,7 @@ struct devfreq *devfreq_add_device(struct device *dev, devfreq->dev.parent = dev; devfreq->dev.class = devfreq_class; devfreq->dev.release = devfreq_dev_release; + INIT_LIST_HEAD(&devfreq->node); devfreq->profile = profile; strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN); devfreq->previous_freq = profile->initial_freq; -- cgit v1.2.3 From b110cf2b747d5ea43c4bbca3ccdb8292203cba2d Mon Sep 17 00:00:00 2001 From: Leonard Crestez Date: Tue, 24 Sep 2019 10:26:53 +0300 Subject: PM / devfreq: Check NULL governor in available_governors_show commit d68adc8f85cd757bd33c8d7b2660ad6f16f7f3dc upstream. The governor is initialized after sysfs attributes become visible so in theory the governor field can be NULL here. Fixes: bcf23c79c4e46 ("PM / devfreq: Fix available_governor sysfs") Signed-off-by: Leonard Crestez Reviewed-by: Matthias Kaehlcke Reviewed-by: Chanwoo Choi Signed-off-by: Chanwoo Choi Signed-off-by: Greg Kroah-Hartman --- drivers/devfreq/devfreq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/devfreq/devfreq.c') diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index fb696957eb21..1ba9d02381e8 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -982,7 +982,7 @@ static ssize_t available_governors_show(struct device *d, * The devfreq with immutable governor (e.g., passive) shows * only own governor. */ - if (df->governor->immutable) { + if (df->governor && df->governor->immutable) { count = scnprintf(&buf[count], DEVFREQ_NAME_LEN, "%s ", df->governor_name); /* -- cgit v1.2.3