@@ -49,9 +49,14 @@ static struct opp_device *_find_opp_dev(const struct device *dev,
static struct opp_table *_find_opp_table_unlocked(struct device *dev)
{
struct opp_table *opp_table;
+ bool found;
list_for_each_entry(opp_table, &opp_tables, node) {
- if (_find_opp_dev(dev, opp_table)) {
+ mutex_lock(&opp_table->lock);
+ found = !!_find_opp_dev(dev, opp_table);
+ mutex_unlock(&opp_table->lock);
+
+ if (found) {
_get_opp_table_kref(opp_table);
return opp_table;
@@ -711,6 +716,8 @@ struct opp_device *_add_opp_dev(const struct device *dev,
/* Initialize opp-dev */
opp_dev->dev = dev;
+
+ mutex_lock(&opp_table->lock);
list_add(&opp_dev->node, &opp_table->dev_list);
/* Create debugfs entries for the opp_table */
@@ -718,6 +725,7 @@ struct opp_device *_add_opp_dev(const struct device *dev,
if (ret)
dev_err(dev, "%s: Failed to register opp debugfs (%d)\n",
__func__, ret);
+ mutex_unlock(&opp_table->lock);
return opp_dev;
}
@@ -736,6 +744,7 @@ static struct opp_table *_allocate_opp_table(struct device *dev)
if (!opp_table)
return NULL;
+ mutex_init(&opp_table->lock);
INIT_LIST_HEAD(&opp_table->dev_list);
opp_dev = _add_opp_dev(dev, opp_table);
@@ -757,7 +766,6 @@ static struct opp_table *_allocate_opp_table(struct device *dev)
BLOCKING_INIT_NOTIFIER_HEAD(&opp_table->head);
INIT_LIST_HEAD(&opp_table->opp_list);
- mutex_init(&opp_table->lock);
kref_init(&opp_table->kref);
/* Secure the device table modification */
@@ -799,6 +807,10 @@ static void _opp_table_kref_release(struct kref *kref)
if (!IS_ERR(opp_table->clk))
clk_put(opp_table->clk);
+ /*
+ * No need to take opp_table->lock here as we are guaranteed that no
+ * references to the OPP table are taken at this point.
+ */
opp_dev = list_first_entry(&opp_table->dev_list, struct opp_device,
node);
@@ -1702,6 +1714,9 @@ void _dev_pm_opp_remove_table(struct opp_table *opp_table, struct device *dev,
{
struct dev_pm_opp *opp, *tmp;
+ /* Protect dev_list */
+ mutex_lock(&opp_table->lock);
+
/* Find if opp_table manages a single device */
if (list_is_singular(&opp_table->dev_list)) {
/* Free static OPPs */
@@ -1712,6 +1727,8 @@ void _dev_pm_opp_remove_table(struct opp_table *opp_table, struct device *dev,
} else {
_remove_opp_dev(_find_opp_dev(dev, opp_table), opp_table);
}
+
+ mutex_unlock(&opp_table->lock);
}
void _dev_pm_opp_find_and_remove_table(struct device *dev, bool remove_all)
@@ -222,8 +222,10 @@ int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
cpumask_clear(cpumask);
if (opp_table->shared_opp == OPP_TABLE_ACCESS_SHARED) {
+ mutex_lock(&opp_table->lock);
list_for_each_entry(opp_dev, &opp_table->dev_list, node)
cpumask_set_cpu(opp_dev->dev->id, cpumask);
+ mutex_unlock(&opp_table->lock);
} else {
cpumask_set_cpu(cpu_dev->id, cpumask);
}
@@ -124,7 +124,7 @@ enum opp_table_access {
* @dev_list: list of devices that share these OPPs
* @opp_list: table of opps
* @kref: for reference count of the table.
- * @lock: mutex protecting the opp_list.
+ * @lock: mutex protecting the opp_list and dev_list.
* @np: struct device_node pointer for opp's DT node.
* @clock_latency_ns_max: Max clock latency in nanoseconds.
* @shared_opp: OPP is shared between multiple devices.
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * This automated bisection report was sent to you on the basis * * that you may be involved with the breaking commit it has * * found. No manual investigation has been done to verify it, * * and the root cause of the problem may be somewhere else. * * * * If you do send a fix, please include this trailer: * * Reported-by: "kernelci.org bot" <bot@kernelci.org> * * * * Hope this helps! * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * stable/linux-4.14.y bisection: boot on odroid-x2 Summary: Start: f56f3d0e65ad Linux 4.14.155 Details: https://kernelci.org/boot/id/5dd5a12159b5143a10cf54c3 Plain log: https://storage.kernelci.org//stable/linux-4.14.y/v4.14.155/arm/exynos_defconfig/gcc-8/lab-collabora/boot-exynos4412-odroidx2.txt HTML log: https://storage.kernelci.org//stable/linux-4.14.y/v4.14.155/arm/exynos_defconfig/gcc-8/lab-collabora/boot-exynos4412-odroidx2.html Result: 714ab224a8db OPP: Protect dev_list with opp_table lock Checks: revert: PASS verify: PASS Parameters: Tree: stable URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git Branch: linux-4.14.y Target: odroid-x2 CPU arch: arm Lab: lab-collabora Compiler: gcc-8 Config: exynos_defconfig Test suite: boot Breaking commit found: ------------------------------------------------------------------------------- commit 714ab224a8db6e8255c61a42613de9349ceb0bba Author: Viresh Kumar <viresh.kumar@linaro.org> Date: Fri Aug 3 07:05:21 2018 +0530 OPP: Protect dev_list with opp_table lock [ Upstream commit 3d2556992a878a2210d3be498416aee39e0c32aa ] The dev_list needs to be protected with a lock, else we may have simultaneous access (addition/removal) to it and that would be racy. Extend scope of the opp_table lock to protect dev_list as well. Tested-by: Niklas Cassel <niklas.cassel@linaro.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org> ------------------------------------------------------------------------------- Git bisection log: ------------------------------------------------------------------------------- git bisect start # good: [775d01b65b5daa002a9ba60f2d2bb3b1a6ce12fb] Linux 4.14.154 git bisect good 775d01b65b5daa002a9ba60f2d2bb3b1a6ce12fb # bad: [f56f3d0e65adb447b8b583c8ed4fbbe544c9bfde] Linux 4.14.155 git bisect bad f56f3d0e65adb447b8b583c8ed4fbbe544c9bfde # good: [46af2022de198ebbf47141b7b33522e28733045d] arm64: dts: meson: Fix erroneous SPI bus warnings git bisect good 46af2022de198ebbf47141b7b33522e28733045d # bad: [0b9c70939b60221f2210ef55a325fec6dea8cde1] media: au0828: Fix incorrect error messages git bisect bad 0b9c70939b60221f2210ef55a325fec6dea8cde1 # bad: [70c3daaa03e965d3f2bd10696be130b376f73bca] net: broadcom: fix return type of ndo_start_xmit function git bisect bad 70c3daaa03e965d3f2bd10696be130b376f73bca # good: [45503ce9086cabc9b3faaaed4563b2da8af1ffe2] samples/bpf: fix a compilation failure git bisect good 45503ce9086cabc9b3faaaed4563b2da8af1ffe2 # good: [9bee4f9f4460db86c47fe01f9671af6a8951efda] powerpc: Fix duplicate const clang warning in user access code git bisect good 9bee4f9f4460db86c47fe01f9671af6a8951efda # bad: [b1fdcfbdb93cc899d19091a2385edb40a07420e3] power: supply: twl4030_charger: fix charging current out-of-bounds git bisect bad b1fdcfbdb93cc899d19091a2385edb40a07420e3 # bad: [714ab224a8db6e8255c61a42613de9349ceb0bba] OPP: Protect dev_list with opp_table lock git bisect bad 714ab224a8db6e8255c61a42613de9349ceb0bba # good: [7dbc3efb7430abdddf0be186bd0ad2611d767d23] RDMA/i40iw: Fix incorrect iterator type git bisect good 7dbc3efb7430abdddf0be186bd0ad2611d767d23 # first bad commit: [714ab224a8db6e8255c61a42613de9349ceb0bba] OPP: Protect dev_list with opp_table lock -------------------------------------------------------------------------------