From: <gregkh@linuxfoundation.org>
To: rafael.j.wysocki@intel.com,lukasz.luba@arm.com,stable@vger.kernel.org
Cc: <stable@vger.kernel.org>
Subject: FAILED: patch "[PATCH] PM: EM: Address RCU-related sparse warnings" failed to apply to 6.13-stable tree
Date: Thu, 17 Apr 2025 12:04:16 +0200 [thread overview]
Message-ID: <2025041716-stack-slacking-56df@gregkh> (raw)
The patch below does not apply to the 6.13-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.13.y
git checkout FETCH_HEAD
git cherry-pick -x 3ee7be9e10dd5f79448788b899591d4bd2bf0c19
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025041716-stack-slacking-56df@gregkh' --subject-prefix 'PATCH 6.13.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 3ee7be9e10dd5f79448788b899591d4bd2bf0c19 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Date: Thu, 6 Mar 2025 17:49:20 +0100
Subject: [PATCH] PM: EM: Address RCU-related sparse warnings
The usage of __rcu in the Energy Model code is quite inconsistent
which causes the following sparse warnings to trigger:
kernel/power/energy_model.c:169:15: warning: incorrect type in assignment (different address spaces)
kernel/power/energy_model.c:169:15: expected struct em_perf_table [noderef] __rcu *table
kernel/power/energy_model.c:169:15: got struct em_perf_table *
kernel/power/energy_model.c:171:9: warning: incorrect type in argument 1 (different address spaces)
kernel/power/energy_model.c:171:9: expected struct callback_head *head
kernel/power/energy_model.c:171:9: got struct callback_head [noderef] __rcu *
kernel/power/energy_model.c:171:9: warning: cast removes address space '__rcu' of expression
kernel/power/energy_model.c:182:19: warning: incorrect type in argument 1 (different address spaces)
kernel/power/energy_model.c:182:19: expected struct kref *kref
kernel/power/energy_model.c:182:19: got struct kref [noderef] __rcu *
kernel/power/energy_model.c:200:15: warning: incorrect type in assignment (different address spaces)
kernel/power/energy_model.c:200:15: expected struct em_perf_table [noderef] __rcu *table
kernel/power/energy_model.c:200:15: got void *[assigned] _res
kernel/power/energy_model.c:204:20: warning: incorrect type in argument 1 (different address spaces)
kernel/power/energy_model.c:204:20: expected struct kref *kref
kernel/power/energy_model.c:204:20: got struct kref [noderef] __rcu *
kernel/power/energy_model.c:320:19: warning: incorrect type in argument 1 (different address spaces)
kernel/power/energy_model.c:320:19: expected struct kref *kref
kernel/power/energy_model.c:320:19: got struct kref [noderef] __rcu *
kernel/power/energy_model.c:325:45: warning: incorrect type in argument 2 (different address spaces)
kernel/power/energy_model.c:325:45: expected struct em_perf_state *table
kernel/power/energy_model.c:325:45: got struct em_perf_state [noderef] __rcu *
kernel/power/energy_model.c:425:45: warning: incorrect type in argument 3 (different address spaces)
kernel/power/energy_model.c:425:45: expected struct em_perf_state *table
kernel/power/energy_model.c:425:45: got struct em_perf_state [noderef] __rcu *
kernel/power/energy_model.c:442:15: warning: incorrect type in argument 1 (different address spaces)
kernel/power/energy_model.c:442:15: expected void const *objp
kernel/power/energy_model.c:442:15: got struct em_perf_table [noderef] __rcu *[assigned] em_table
kernel/power/energy_model.c:626:55: warning: incorrect type in argument 2 (different address spaces)
kernel/power/energy_model.c:626:55: expected struct em_perf_state *table
kernel/power/energy_model.c:626:55: got struct em_perf_state [noderef] __rcu *
kernel/power/energy_model.c:681:16: warning: incorrect type in assignment (different address spaces)
kernel/power/energy_model.c:681:16: expected struct em_perf_state *new_ps
kernel/power/energy_model.c:681:16: got struct em_perf_state [noderef] __rcu *
kernel/power/energy_model.c:699:37: warning: incorrect type in argument 2 (different address spaces)
kernel/power/energy_model.c:699:37: expected struct em_perf_state *table
kernel/power/energy_model.c:699:37: got struct em_perf_state [noderef] __rcu *
kernel/power/energy_model.c:733:38: warning: incorrect type in argument 3 (different address spaces)
kernel/power/energy_model.c:733:38: expected struct em_perf_state *table
kernel/power/energy_model.c:733:38: got struct em_perf_state [noderef] __rcu *
kernel/power/energy_model.c:855:53: warning: dereference of noderef expression
kernel/power/energy_model.c:864:32: warning: dereference of noderef expression
This is because the __rcu annotation for sparse is only applicable to
pointers that need rcu_dereference() or equivalent for protection, which
basically means pointers assigned with rcu_assign_pointer().
Make all of the above sparse warnings go away by cleaning up the usage
of __rcu and using rcu_dereference_protected() where applicable.
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://patch.msgid.link/5885405.DvuYhMxLoT@rjwysocki.net
diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
index b23c8c798dac..ddd09debfc7d 100644
--- a/include/linux/energy_model.h
+++ b/include/linux/energy_model.h
@@ -167,13 +167,13 @@ struct em_data_callback {
struct em_perf_domain *em_cpu_get(int cpu);
struct em_perf_domain *em_pd_get(struct device *dev);
int em_dev_update_perf_domain(struct device *dev,
- struct em_perf_table __rcu *new_table);
+ struct em_perf_table *new_table);
int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
const struct em_data_callback *cb,
const cpumask_t *cpus, bool microwatts);
void em_dev_unregister_perf_domain(struct device *dev);
-struct em_perf_table __rcu *em_table_alloc(struct em_perf_domain *pd);
-void em_table_free(struct em_perf_table __rcu *table);
+struct em_perf_table *em_table_alloc(struct em_perf_domain *pd);
+void em_table_free(struct em_perf_table *table);
int em_dev_compute_costs(struct device *dev, struct em_perf_state *table,
int nr_states);
int em_dev_update_chip_binning(struct device *dev);
@@ -373,14 +373,14 @@ static inline int em_pd_nr_perf_states(struct em_perf_domain *pd)
return 0;
}
static inline
-struct em_perf_table __rcu *em_table_alloc(struct em_perf_domain *pd)
+struct em_perf_table *em_table_alloc(struct em_perf_domain *pd)
{
return NULL;
}
-static inline void em_table_free(struct em_perf_table __rcu *table) {}
+static inline void em_table_free(struct em_perf_table *table) {}
static inline
int em_dev_update_perf_domain(struct device *dev,
- struct em_perf_table __rcu *new_table)
+ struct em_perf_table *new_table)
{
return -EINVAL;
}
diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c
index 1e3caa96c271..d9b7e2b38c7a 100644
--- a/kernel/power/energy_model.c
+++ b/kernel/power/energy_model.c
@@ -163,12 +163,8 @@ static void em_debug_remove_pd(struct device *dev) {}
static void em_release_table_kref(struct kref *kref)
{
- struct em_perf_table __rcu *table;
-
/* It was the last owner of this table so we can free */
- table = container_of(kref, struct em_perf_table, kref);
-
- kfree_rcu(table, rcu);
+ kfree_rcu(container_of(kref, struct em_perf_table, kref), rcu);
}
/**
@@ -177,7 +173,7 @@ static void em_release_table_kref(struct kref *kref)
*
* No return values.
*/
-void em_table_free(struct em_perf_table __rcu *table)
+void em_table_free(struct em_perf_table *table)
{
kref_put(&table->kref, em_release_table_kref);
}
@@ -190,9 +186,9 @@ void em_table_free(struct em_perf_table __rcu *table)
* has a user.
* Returns allocated table or NULL.
*/
-struct em_perf_table __rcu *em_table_alloc(struct em_perf_domain *pd)
+struct em_perf_table *em_table_alloc(struct em_perf_domain *pd)
{
- struct em_perf_table __rcu *table;
+ struct em_perf_table *table;
int table_size;
table_size = sizeof(struct em_perf_state) * pd->nr_perf_states;
@@ -300,9 +296,9 @@ int em_dev_compute_costs(struct device *dev, struct em_perf_state *table,
* Return 0 on success or an error code on failure.
*/
int em_dev_update_perf_domain(struct device *dev,
- struct em_perf_table __rcu *new_table)
+ struct em_perf_table *new_table)
{
- struct em_perf_table __rcu *old_table;
+ struct em_perf_table *old_table;
struct em_perf_domain *pd;
if (!dev)
@@ -319,7 +315,8 @@ int em_dev_update_perf_domain(struct device *dev,
kref_get(&new_table->kref);
- old_table = pd->em_table;
+ old_table = rcu_dereference_protected(pd->em_table,
+ lockdep_is_held(&em_pd_mutex));
rcu_assign_pointer(pd->em_table, new_table);
em_cpufreq_update_efficiencies(dev, new_table->state);
@@ -392,7 +389,7 @@ static int em_create_pd(struct device *dev, int nr_states,
const cpumask_t *cpus,
unsigned long flags)
{
- struct em_perf_table __rcu *em_table;
+ struct em_perf_table *em_table;
struct em_perf_domain *pd;
struct device *cpu_dev;
int cpu, ret, num_cpus;
@@ -552,6 +549,7 @@ int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
const struct em_data_callback *cb,
const cpumask_t *cpus, bool microwatts)
{
+ struct em_perf_table *em_table;
unsigned long cap, prev_cap = 0;
unsigned long flags = 0;
int cpu, ret;
@@ -624,7 +622,9 @@ int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
dev->em_pd->min_perf_state = 0;
dev->em_pd->max_perf_state = nr_states - 1;
- em_cpufreq_update_efficiencies(dev, dev->em_pd->em_table->state);
+ em_table = rcu_dereference_protected(dev->em_pd->em_table,
+ lockdep_is_held(&em_pd_mutex));
+ em_cpufreq_update_efficiencies(dev, em_table->state);
em_debug_create_pd(dev);
dev_info(dev, "EM: created perf domain\n");
@@ -661,7 +661,8 @@ void em_dev_unregister_perf_domain(struct device *dev)
mutex_lock(&em_pd_mutex);
em_debug_remove_pd(dev);
- em_table_free(dev->em_pd->em_table);
+ em_table_free(rcu_dereference_protected(dev->em_pd->em_table,
+ lockdep_is_held(&em_pd_mutex)));
kfree(dev->em_pd);
dev->em_pd = NULL;
@@ -669,9 +670,9 @@ void em_dev_unregister_perf_domain(struct device *dev)
}
EXPORT_SYMBOL_GPL(em_dev_unregister_perf_domain);
-static struct em_perf_table __rcu *em_table_dup(struct em_perf_domain *pd)
+static struct em_perf_table *em_table_dup(struct em_perf_domain *pd)
{
- struct em_perf_table __rcu *em_table;
+ struct em_perf_table *em_table;
struct em_perf_state *ps, *new_ps;
int ps_size;
@@ -693,7 +694,7 @@ static struct em_perf_table __rcu *em_table_dup(struct em_perf_domain *pd)
}
static int em_recalc_and_update(struct device *dev, struct em_perf_domain *pd,
- struct em_perf_table __rcu *em_table)
+ struct em_perf_table *em_table)
{
int ret;
@@ -723,7 +724,7 @@ static int em_recalc_and_update(struct device *dev, struct em_perf_domain *pd,
static void em_adjust_new_capacity(struct device *dev,
struct em_perf_domain *pd)
{
- struct em_perf_table __rcu *em_table;
+ struct em_perf_table *em_table;
em_table = em_table_dup(pd);
if (!em_table) {
@@ -814,7 +815,7 @@ static void em_update_workfn(struct work_struct *work)
*/
int em_dev_update_chip_binning(struct device *dev)
{
- struct em_perf_table __rcu *em_table;
+ struct em_perf_table *em_table;
struct em_perf_domain *pd;
int i, ret;
reply other threads:[~2025-04-17 10:04 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=2025041716-stack-slacking-56df@gregkh \
--to=gregkh@linuxfoundation.org \
--cc=lukasz.luba@arm.com \
--cc=rafael.j.wysocki@intel.com \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.