6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Johan Hovold johan+linaro@kernel.org
commit 7b439aaa62fee474a0d84d67a25f4984467e7b95 upstream.
The Qualcomm SPMI PMIC revid implementation is broken in multiple ways.
First, it assumes that just because the sibling base device has been registered that means that it is also bound to a driver, which may not be the case (e.g. due to probe deferral or asynchronous probe). This could trigger a NULL-pointer dereference when attempting to access the driver data of the unbound device.
Second, it accesses driver data of a sibling device directly and without any locking, which means that the driver data may be freed while it is being accessed (e.g. on driver unbind).
Third, it leaks a struct device reference to the sibling device which is looked up using the spmi_device_from_of() every time a function (child) device is calling the revid function (e.g. on probe).
Fix this mess by reimplementing the revid lookup so that it is done only at probe of the PMIC device; the base device fetches the revid info from the hardware, while any secondary SPMI device fetches the information from the base device and caches it so that it can be accessed safely from its children. If the base device has not been probed yet then probe of a secondary device is deferred.
Fixes: e9c11c6e3a0e ("mfd: qcom-spmi-pmic: expose the PMIC revid information to clients") Cc: stable@vger.kernel.org # 6.0 Signed-off-by: Johan Hovold johan+linaro@kernel.org Acked-by: Caleb Connolly caleb.connolly@linaro.org Link: https://lore.kernel.org/r/20231003152927.15000-3-johan+linaro@kernel.org Signed-off-by: Lee Jones lee@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/mfd/qcom-spmi-pmic.c | 69 +++++++++++++++++++++++++++++++++---------- 1 file changed, 53 insertions(+), 16 deletions(-)
--- a/drivers/mfd/qcom-spmi-pmic.c +++ b/drivers/mfd/qcom-spmi-pmic.c @@ -30,6 +30,8 @@ struct qcom_spmi_dev { struct qcom_spmi_pmic pmic; };
+static DEFINE_MUTEX(pmic_spmi_revid_lock); + #define N_USIDS(n) ((void *)n)
static const struct of_device_id pmic_spmi_id_table[] = { @@ -76,24 +78,21 @@ static const struct of_device_id pmic_sp * * This only supports PMICs with 1 or 2 USIDs. */ -static struct spmi_device *qcom_pmic_get_base_usid(struct device *dev) +static struct spmi_device *qcom_pmic_get_base_usid(struct spmi_device *sdev, struct qcom_spmi_dev *ctx) { - struct spmi_device *sdev; - struct qcom_spmi_dev *ctx; struct device_node *spmi_bus; struct device_node *child; int function_parent_usid, ret; u32 pmic_addr;
- sdev = to_spmi_device(dev); - ctx = dev_get_drvdata(&sdev->dev); - /* * Quick return if the function device is already in the base * USID. This will always be hit for PMICs with only 1 USID. */ - if (sdev->usid % ctx->num_usids == 0) + if (sdev->usid % ctx->num_usids == 0) { + get_device(&sdev->dev); return sdev; + }
function_parent_usid = sdev->usid;
@@ -118,10 +117,8 @@ static struct spmi_device *qcom_pmic_get sdev = spmi_device_from_of(child); if (!sdev) { /* - * If the base USID for this PMIC hasn't probed yet - * but the secondary USID has, then we need to defer - * the function driver so that it will attempt to - * probe again when the base USID is ready. + * If the base USID for this PMIC hasn't been + * registered yet then we need to defer. */ sdev = ERR_PTR(-EPROBE_DEFER); } @@ -135,6 +132,35 @@ static struct spmi_device *qcom_pmic_get return sdev; }
+static int pmic_spmi_get_base_revid(struct spmi_device *sdev, struct qcom_spmi_dev *ctx) +{ + struct qcom_spmi_dev *base_ctx; + struct spmi_device *base; + int ret = 0; + + base = qcom_pmic_get_base_usid(sdev, ctx); + if (IS_ERR(base)) + return PTR_ERR(base); + + /* + * Copy revid info from base device if it has probed and is still + * bound to its driver. + */ + mutex_lock(&pmic_spmi_revid_lock); + base_ctx = spmi_device_get_drvdata(base); + if (!base_ctx) { + ret = -EPROBE_DEFER; + goto out_unlock; + } + memcpy(&ctx->pmic, &base_ctx->pmic, sizeof(ctx->pmic)); +out_unlock: + mutex_unlock(&pmic_spmi_revid_lock); + + put_device(&base->dev); + + return ret; +} + static int pmic_spmi_load_revid(struct regmap *map, struct device *dev, struct qcom_spmi_pmic *pmic) { @@ -210,11 +236,7 @@ const struct qcom_spmi_pmic *qcom_pmic_g if (!of_match_device(pmic_spmi_id_table, dev->parent)) return ERR_PTR(-EINVAL);
- sdev = qcom_pmic_get_base_usid(dev->parent); - - if (IS_ERR(sdev)) - return ERR_CAST(sdev); - + sdev = to_spmi_device(dev->parent); spmi = dev_get_drvdata(&sdev->dev);
return &spmi->pmic; @@ -249,16 +271,31 @@ static int pmic_spmi_probe(struct spmi_d ret = pmic_spmi_load_revid(regmap, &sdev->dev, &ctx->pmic); if (ret < 0) return ret; + } else { + ret = pmic_spmi_get_base_revid(sdev, ctx); + if (ret) + return ret; } + + mutex_lock(&pmic_spmi_revid_lock); spmi_device_set_drvdata(sdev, ctx); + mutex_unlock(&pmic_spmi_revid_lock);
return devm_of_platform_populate(&sdev->dev); }
+static void pmic_spmi_remove(struct spmi_device *sdev) +{ + mutex_lock(&pmic_spmi_revid_lock); + spmi_device_set_drvdata(sdev, NULL); + mutex_unlock(&pmic_spmi_revid_lock); +} + MODULE_DEVICE_TABLE(of, pmic_spmi_id_table);
static struct spmi_driver pmic_spmi_driver = { .probe = pmic_spmi_probe, + .remove = pmic_spmi_remove, .driver = { .name = "pmic-spmi", .of_match_table = pmic_spmi_id_table,