Prevent USB runtime PM (autosuspend) for AX88772* in bind.
usbnet enables runtime PM (autosuspend) by default, so disabling it via
the usb_driver flag is ineffective. On AX88772B, autosuspend shows no
measurable power saving with current driver (no link partner, admin
up/down). The ~0.453 W -> ~0.248 W drop on v6.1 comes from phylib powering
the PHY off on admin-down, not from USB autosuspend.
The real hazard is that with runtime PM enabled, ndo_open() (under RTNL)
may synchronously trigger autoresume (usb_autopm_get_interface()) into
asix_resume() while the USB PM lock is held. Resume paths then invoke
phylink/phylib and MDIO, which also expect RTNL, leading to possible
deadlocks or PM lock vs MDIO wake issues.
To avoid this, keep the device runtime-PM active by taking a usage
reference in ax88772_bind() and dropping it in unbind(). A non-zero PM
usage count blocks runtime suspend regardless of userspace policy
(.../power/control - pm_runtime_allow/forbid), making this approach
robust against sysfs overrides.
Holding a runtime-PM usage ref does not affect system-wide suspend;
system sleep/resume callbacks continue to run as before.
Fixes: 4a2c7217cd5a ("net: usb: asix: ax88772: manage PHY PM from MAC")
Reported-by: Hubert Wiśniewski <hubert.wisniewski.25632(a)gmail.com>
Closes: https://lore.kernel.org/all/DCGHG5UJT9G3.2K1GHFZ3H87T0@gmail.com
Tested-by: Hubert Wiśniewski <hubert.wisniewski.25632(a)gmail.com>
Reported-by: Marek Szyprowski <m.szyprowski(a)samsung.com>
Closes: https://lore.kernel.org/all/b5ea8296-f981-445d-a09a-2f389d7f6fdd@samsung.com
Cc: stable(a)vger.kernel.org
Signed-off-by: Oleksij Rempel <o.rempel(a)pengutronix.de>
---
changes v3
- update comments and commit message
changes v2:
- Switch from pm_runtime_forbid()/allow() to pm_runtime_get_noresume()/put()
as suggested by Alan Stern, to block autosuspend robustly.
- Reword commit message to clarify the actual deadlock condition
(autoresume under RTNL) as pointed out by Oliver Neukum.
- Keep explanation in commit message, shorten in-code comment.
Link to the measurement results:
https://lore.kernel.org/all/aMkPMa650kfKfmF4@pengutronix.de/
---
drivers/net/usb/asix_devices.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c
index 792ddda1ad49..85bd5d845409 100644
--- a/drivers/net/usb/asix_devices.c
+++ b/drivers/net/usb/asix_devices.c
@@ -625,6 +625,21 @@ static void ax88772_suspend(struct usbnet *dev)
asix_read_medium_status(dev, 1));
}
+/* Notes on PM callbacks and locking context:
+ *
+ * - asix_suspend()/asix_resume() are invoked for both runtime PM and
+ * system-wide suspend/resume. For struct usb_driver the ->resume()
+ * callback does not receive pm_message_t, so the resume type cannot
+ * be distinguished here.
+ *
+ * - The MAC driver must hold RTNL when calling phylink interfaces such as
+ * phylink_suspend()/resume(). Those calls will also perform MDIO I/O.
+ *
+ * - Taking RTNL and doing MDIO from a runtime-PM resume callback (while
+ * the USB PM lock is held) is fragile. Since autosuspend brings no
+ * measurable power saving here, we block it by holding a PM usage
+ * reference in ax88772_bind().
+ */
static int asix_suspend(struct usb_interface *intf, pm_message_t message)
{
struct usbnet *dev = usb_get_intfdata(intf);
@@ -919,6 +934,13 @@ static int ax88772_bind(struct usbnet *dev, struct usb_interface *intf)
if (ret)
goto initphy_err;
+ /* Keep this interface runtime-PM active by taking a usage ref.
+ * Prevents runtime suspend while bound and avoids resume paths
+ * that could deadlock (autoresume under RTNL while USB PM lock
+ * is held, phylink/MDIO wants RTNL).
+ */
+ pm_runtime_get_noresume(&intf->dev);
+
return 0;
initphy_err:
@@ -948,6 +970,8 @@ static void ax88772_unbind(struct usbnet *dev, struct usb_interface *intf)
phylink_destroy(priv->phylink);
ax88772_mdio_unregister(priv);
asix_rx_fixup_common_free(dev->driver_priv);
+ /* Drop the PM usage ref taken in bind() */
+ pm_runtime_put(&intf->dev);
}
static void ax88178_unbind(struct usbnet *dev, struct usb_interface *intf)
@@ -1600,6 +1624,11 @@ static struct usb_driver asix_driver = {
.resume = asix_resume,
.reset_resume = asix_resume,
.disconnect = usbnet_disconnect,
+ /* usbnet enables autosuspend by default (supports_autosuspend=1).
+ * We keep runtime-PM active for AX88772* by taking a PM usage
+ * reference in ax88772_bind() (pm_runtime_get_noresume()) and
+ * dropping it in unbind(), which effectively blocks autosuspend.
+ */
.supports_autosuspend = 1,
.disable_hub_initiated_lpm = 1,
};
--
2.47.3
Make sure to drop the reference taken to the iommu platform device when
looking up its driver data during of_xlate().
Note that commit 1a26044954a6 ("iommu/exynos: add missing put_device()
call in exynos_iommu_of_xlate()") fixed the leak in a couple of error
paths, but the reference is still leaking on success.
Fixes: aa759fd376fb ("iommu/exynos: Add callback for initializing devices from device tree")
Cc: stable(a)vger.kernel.org # 4.2: 1a26044954a6
Cc: Marek Szyprowski <m.szyprowski(a)samsung.com>
Cc: Yu Kuai <yukuai3(a)huawei.com>
Acked-by: Robin Murphy <robin.murphy(a)arm.com>
Signed-off-by: Johan Hovold <johan(a)kernel.org>
---
drivers/iommu/exynos-iommu.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index b6edd178fe25..ce9e935cb84c 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -1446,17 +1446,14 @@ static int exynos_iommu_of_xlate(struct device *dev,
return -ENODEV;
data = platform_get_drvdata(sysmmu);
- if (!data) {
- put_device(&sysmmu->dev);
+ put_device(&sysmmu->dev);
+ if (!data)
return -ENODEV;
- }
if (!owner) {
owner = kzalloc(sizeof(*owner), GFP_KERNEL);
- if (!owner) {
- put_device(&sysmmu->dev);
+ if (!owner)
return -ENOMEM;
- }
INIT_LIST_HEAD(&owner->controllers);
mutex_init(&owner->rpm_lock);
--
2.49.1
Make sure to drop the references taken to the iommu platform devices
when looking up their driver data during probe_device().
Note that the arch data device pointer added by commit 604629bcb505
("iommu/omap: add support for late attachment of iommu devices") has
never been used. Remove it to underline that the references are not
needed.
Fixes: 9d5018deec86 ("iommu/omap: Add support to program multiple iommus")
Fixes: 7d6827748d54 ("iommu/omap: Fix iommu archdata name for DT-based devices")
Cc: stable(a)vger.kernel.org # 3.18
Cc: Suman Anna <s-anna(a)ti.com>
Acked-by: Robin Murphy <robin.murphy(a)arm.com>
Signed-off-by: Johan Hovold <johan(a)kernel.org>
---
drivers/iommu/omap-iommu.c | 2 +-
drivers/iommu/omap-iommu.h | 2 --
2 files changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index 6fb93927bdb9..b87ce129fb1f 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -1675,6 +1675,7 @@ static struct iommu_device *omap_iommu_probe_device(struct device *dev)
}
oiommu = platform_get_drvdata(pdev);
+ put_device(&pdev->dev);
if (!oiommu) {
of_node_put(np);
kfree(arch_data);
@@ -1682,7 +1683,6 @@ static struct iommu_device *omap_iommu_probe_device(struct device *dev)
}
tmp->iommu_dev = oiommu;
- tmp->dev = &pdev->dev;
of_node_put(np);
}
diff --git a/drivers/iommu/omap-iommu.h b/drivers/iommu/omap-iommu.h
index 27697109ec79..50b39be61abc 100644
--- a/drivers/iommu/omap-iommu.h
+++ b/drivers/iommu/omap-iommu.h
@@ -88,7 +88,6 @@ struct omap_iommu {
/**
* struct omap_iommu_arch_data - omap iommu private data
* @iommu_dev: handle of the OMAP iommu device
- * @dev: handle of the iommu device
*
* This is an omap iommu private data object, which binds an iommu user
* to its iommu device. This object should be placed at the iommu user's
@@ -97,7 +96,6 @@ struct omap_iommu {
*/
struct omap_iommu_arch_data {
struct omap_iommu *iommu_dev;
- struct device *dev;
};
struct cr_regs {
--
2.49.1
Make sure to drop the reference taken to the iommu platform device when
looking up its driver data during of_xlate().
Fixes: 7b2d59611fef ("iommu/ipmmu-vmsa: Replace local utlb code with fwspec ids")
Cc: stable(a)vger.kernel.org # 4.14
Cc: Magnus Damm <damm+renesas(a)opensource.se>
Acked-by: Robin Murphy <robin.murphy(a)arm.com>
Signed-off-by: Johan Hovold <johan(a)kernel.org>
---
drivers/iommu/ipmmu-vmsa.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index ffa892f65714..02a2a55ffa0a 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -720,6 +720,8 @@ static int ipmmu_init_platform_device(struct device *dev,
dev_iommu_priv_set(dev, platform_get_drvdata(ipmmu_pdev));
+ put_device(&ipmmu_pdev->dev);
+
return 0;
}
--
2.49.1
Make sure to drop the reference taken to the iommu platform device when
looking up its driver data during of_xlate().
Note that commit e2eae09939a8 ("iommu/qcom: add missing put_device()
call in qcom_iommu_of_xlate()") fixed the leak in a couple of error
paths, but the reference is still leaking on success and late failures.
Fixes: 0ae349a0f33f ("iommu/qcom: Add qcom_iommu")
Cc: stable(a)vger.kernel.org # 4.14: e2eae09939a8
Cc: Rob Clark <robin.clark(a)oss.qualcomm.com>
Cc: Yu Kuai <yukuai3(a)huawei.com>
Acked-by: Robin Murphy <robin.murphy(a)arm.com>
Signed-off-by: Johan Hovold <johan(a)kernel.org>
---
drivers/iommu/arm/arm-smmu/qcom_iommu.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
index c5be95e56031..9c1166a3af6c 100644
--- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
+++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
@@ -565,14 +565,14 @@ static int qcom_iommu_of_xlate(struct device *dev,
qcom_iommu = platform_get_drvdata(iommu_pdev);
+ put_device(&iommu_pdev->dev);
+
/* make sure the asid specified in dt is valid, so we don't have
* to sanity check this elsewhere:
*/
if (WARN_ON(asid > qcom_iommu->max_asid) ||
- WARN_ON(qcom_iommu->ctxs[asid] == NULL)) {
- put_device(&iommu_pdev->dev);
+ WARN_ON(qcom_iommu->ctxs[asid] == NULL))
return -EINVAL;
- }
if (!dev_iommu_priv_get(dev)) {
dev_iommu_priv_set(dev, qcom_iommu);
@@ -581,10 +581,8 @@ static int qcom_iommu_of_xlate(struct device *dev,
* multiple different iommu devices. Multiple context
* banks are ok, but multiple devices are not:
*/
- if (WARN_ON(qcom_iommu != dev_iommu_priv_get(dev))) {
- put_device(&iommu_pdev->dev);
+ if (WARN_ON(qcom_iommu != dev_iommu_priv_get(dev)))
return -EINVAL;
- }
}
return iommu_fwspec_add_ids(dev, &asid, 1);
--
2.49.1
Make sure to drop the reference taken to the iommu platform device when
looking up its driver data during of_xlate().
Fixes: 46d1fb072e76 ("iommu/dart: Add DART iommu driver")
Cc: stable(a)vger.kernel.org # 5.15
Cc: Sven Peter <sven(a)kernel.org>
Acked-by: Robin Murphy <robin.murphy(a)arm.com>
Signed-off-by: Johan Hovold <johan(a)kernel.org>
---
drivers/iommu/apple-dart.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
index 190f28d76615..1aa7c10262a8 100644
--- a/drivers/iommu/apple-dart.c
+++ b/drivers/iommu/apple-dart.c
@@ -790,6 +790,8 @@ static int apple_dart_of_xlate(struct device *dev,
struct apple_dart *cfg_dart;
int i, sid;
+ put_device(&iommu_pdev->dev);
+
if (args->args_count != 1)
return -EINVAL;
sid = args->args[0];
--
2.49.1