@@ -48,9 +48,14 @@ 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;
@@ -766,6 +771,8 @@ 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 */
@@ -773,6 +780,7 @@ 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;
}
@@ -791,6 +799,7 @@ 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);
@@ -812,7 +821,6 @@ 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 */
@@ -854,6 +862,10 @@ 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);
@@ -1719,6 +1731,9 @@ 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 */
@@ -1736,6 +1751,8 @@ 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);
}
@@ -126,7 +126,7 @@ 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-4.19.y bisection: boot on odroid-xu3 Summary: Start: c63ee2939dc1 Linux 4.19.85 Details: https://kernelci.org/boot/id/5dd5baaa59b5145b6ecf54c3 Plain log: https://storage.kernelci.org//stable/linux-4.19.y/v4.19.85/arm/exynos_defconfig/gcc-8/lab-collabora/boot-exynos5422-odroidxu3.txt HTML log: https://storage.kernelci.org//stable/linux-4.19.y/v4.19.85/arm/exynos_defconfig/gcc-8/lab-collabora/boot-exynos5422-odroidxu3.html Result: 4c64ce947cfa 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-4.19.y Target: odroid-xu3 CPU arch: arm Lab: lab-collabora Compiler: gcc-8 Config: exynos_defconfig Test suite: boot Breaking commit found: ------------------------------------------------------------------------------- commit 4c64ce947cfa447993efe005cbaad7ba31a91612 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: [c555efaf14026c7751fa68d87403a5eb5ae7dcaf] Linux 4.19.84 git bisect good c555efaf14026c7751fa68d87403a5eb5ae7dcaf # bad: [c63ee2939dc1c6eee6c544af1b4ab441490bfe6e] Linux 4.19.85 git bisect bad c63ee2939dc1c6eee6c544af1b4ab441490bfe6e # good: [8ac08053744cdd9cc88c26857f5ff48583e995ac] ARM: dts: socfpga: Fix I2C bus unit-address error git bisect good 8ac08053744cdd9cc88c26857f5ff48583e995ac # bad: [cab175f881c578cb16679cb2777c9d6ececafd31] net: micrel: fix return type of ndo_start_xmit function git bisect bad cab175f881c578cb16679cb2777c9d6ececafd31 # good: [eb355ccfdf1dc692670a0fb46feeda02e6cf7af9] powerpc: Fix duplicate const clang warning in user access code git bisect good eb355ccfdf1dc692670a0fb46feeda02e6cf7af9 # bad: [59d6e59f32cc01848dd31a932f22769bba5c4598] s390/vdso: correct CFI annotations of vDSO functions git bisect bad 59d6e59f32cc01848dd31a932f22769bba5c4598 # bad: [5d52c10c345ddd0a2974db3819348318883dd0c7] net: amd: fix return type of ndo_start_xmit function git bisect bad 5d52c10c345ddd0a2974db3819348318883dd0c7 # bad: [773fb69e430751062015467e9f97f35158bd3bf9] power: supply: twl4030_charger: fix charging current out-of-bounds git bisect bad 773fb69e430751062015467e9f97f35158bd3bf9 # bad: [4c64ce947cfa447993efe005cbaad7ba31a91612] OPP: Protect dev_list with opp_table lock git bisect bad 4c64ce947cfa447993efe005cbaad7ba31a91612 # good: [51e509caf5fad3a50860d588227bb6ae4388c7f2] ARM: dts: atmel: Fix I2C and SPI bus warnings git bisect good 51e509caf5fad3a50860d588227bb6ae4388c7f2 # first bad commit: [4c64ce947cfa447993efe005cbaad7ba31a91612] OPP: Protect dev_list with opp_table lock -------------------------------------------------------------------------------