[PATCH v7 00/12] Fix broken usage of driver_override (and kfree of static memory)
Hi,
This is a continuation of my old patchset from 2019. [1] Back then, few drivers set driver_override wrong. I fixed Exynos in a different way after discussions. QCOM NGD was not fixed and a new user appeared - IMX SCU.
It seems "char *" in driver_override looks too consty, so we tend to make a mistake of storing there string literals.
Changes since latest v7 ======================= 1. Patch #1: remove out_free label, document clearing override in kerneldoc and in code-comments (Andy). 2. Patch #12 (rpmsg): do not duplicate string (Biju).
Changes since latest v6 ======================= 1. Patch #1: Don't check for !dev and handle len==0 (Andy). 2. New patch #11 (rpmsg): split constifying of local variable to a new patch.
Changes since latest v5 ======================= 1. Patch #11 (rpmsg): split from previous patch 11 - easier to understand the need of it. 2. Fix build issue in patch 12 (rpmsg).
Changes since latest v4 ======================= 1. Correct commit msgs and comments after Andy's review. 2. Re-order code in new helper (patch #1) (Andy). 3. Add tags.
Changes since latest v3 ======================= 1. Wrap comments, extend comment in driver_set_override() about newline. 2. Minor commit msg fixes. 3. Add tags.
Changes since latest v2 ======================= 1. Make all driver_override fields as "const char *", just like SPI and VDPA. (Mark) 2. Move "count" check to the new helper and add "count" argument. (Michael) 3. Fix typos in docs, patch subject. Extend doc. (Michael, Bjorn) 4. Compare pointers to reduce number of string readings in the helper. 5. Fix clk-imx return value.
Changes since latest v1 (not the old 2019 solution): ==================================================== https://lore.kernel.org/all/708eabb1-7b35-d525-d4c3-451d4a3de84f@rasmusville... 1. Add helper for setting driver_override. 2. Use the helper.
Dependencies (and stable): ========================== 1. All patches, including last three fixes, depend on the first patch introducing the helper. 2. The last three commits - fixes - are probably not backportable directly, because of this dependency. I don't know how to express this dependency here, since stable-kernel-rules.rst mentions only commits as possible dependencies.
[1] https://lore.kernel.org/all/1550484960-2392-3-git-send-email-krzk@kernel.org...
Best regards, Krzysztof
Krzysztof Kozlowski (12): driver: platform: Add helper for safer setting of driver_override amba: Use driver_set_override() instead of open-coding fsl-mc: Use driver_set_override() instead of open-coding hv: Use driver_set_override() instead of open-coding PCI: Use driver_set_override() instead of open-coding s390/cio: Use driver_set_override() instead of open-coding spi: Use helper for safer setting of driver_override vdpa: Use helper for safer setting of driver_override clk: imx: scu: Fix kfree() of static memory on setting driver_override slimbus: qcom-ngd: Fix kfree() of static memory on setting driver_override rpmsg: Constify local variable in field store macro rpmsg: Fix kfree() of static memory on setting driver_override
drivers/amba/bus.c | 28 ++----------- drivers/base/driver.c | 69 +++++++++++++++++++++++++++++++++ drivers/base/platform.c | 28 ++----------- drivers/bus/fsl-mc/fsl-mc-bus.c | 25 ++---------- drivers/clk/imx/clk-scu.c | 7 +++- drivers/hv/vmbus_drv.c | 28 ++----------- drivers/pci/pci-sysfs.c | 28 ++----------- drivers/rpmsg/rpmsg_core.c | 3 +- drivers/rpmsg/rpmsg_internal.h | 13 ++++++- drivers/rpmsg/rpmsg_ns.c | 14 ++++++- drivers/s390/cio/cio.h | 6 ++- drivers/s390/cio/css.c | 28 ++----------- drivers/slimbus/qcom-ngd-ctrl.c | 13 ++++++- drivers/spi/spi.c | 26 ++----------- drivers/vdpa/vdpa.c | 29 ++------------ include/linux/amba/bus.h | 6 ++- include/linux/device/driver.h | 2 + include/linux/fsl/mc.h | 6 ++- include/linux/hyperv.h | 6 ++- include/linux/pci.h | 6 ++- include/linux/platform_device.h | 6 ++- include/linux/rpmsg.h | 6 ++- include/linux/spi/spi.h | 2 + include/linux/vdpa.h | 4 +- 24 files changed, 184 insertions(+), 205 deletions(-)
Several core drivers and buses expect that driver_override is a dynamically allocated memory thus later they can kfree() it.
However such assumption is not documented, there were in the past and there are already users setting it to a string literal. This leads to kfree() of static memory during device release (e.g. in error paths or during unbind):
kernel BUG at ../mm/slub.c:3960! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM ... (kfree) from [<c058da50>] (platform_device_release+0x88/0xb4) (platform_device_release) from [<c0585be0>] (device_release+0x2c/0x90) (device_release) from [<c0a69050>] (kobject_put+0xec/0x20c) (kobject_put) from [<c0f2f120>] (exynos5_clk_probe+0x154/0x18c) (exynos5_clk_probe) from [<c058de70>] (platform_drv_probe+0x6c/0xa4) (platform_drv_probe) from [<c058b7ac>] (really_probe+0x280/0x414) (really_probe) from [<c058baf4>] (driver_probe_device+0x78/0x1c4) (driver_probe_device) from [<c0589854>] (bus_for_each_drv+0x74/0xb8) (bus_for_each_drv) from [<c058b48c>] (__device_attach+0xd4/0x16c) (__device_attach) from [<c058a638>] (bus_probe_device+0x88/0x90) (bus_probe_device) from [<c05871fc>] (device_add+0x3dc/0x62c) (device_add) from [<c075ff10>] (of_platform_device_create_pdata+0x94/0xbc) (of_platform_device_create_pdata) from [<c07600ec>] (of_platform_bus_create+0x1a8/0x4fc) (of_platform_bus_create) from [<c0760150>] (of_platform_bus_create+0x20c/0x4fc) (of_platform_bus_create) from [<c07605f0>] (of_platform_populate+0x84/0x118) (of_platform_populate) from [<c0f3c964>] (of_platform_default_populate_init+0xa0/0xb8) (of_platform_default_populate_init) from [<c01031f8>] (do_one_initcall+0x8c/0x404)
Provide a helper which clearly documents the usage of driver_override. This will allow later to reuse the helper and reduce the amount of duplicated code.
Convert the platform driver to use a new helper and make the driver_override field const char (it is not modified by the core).
Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org --- drivers/base/driver.c | 69 +++++++++++++++++++++++++++++++++ drivers/base/platform.c | 28 ++----------- include/linux/device/driver.h | 2 + include/linux/platform_device.h | 6 ++- 4 files changed, 80 insertions(+), 25 deletions(-)
diff --git a/drivers/base/driver.c b/drivers/base/driver.c index 8c0d33e182fd..1b9d47b10bd0 100644 --- a/drivers/base/driver.c +++ b/drivers/base/driver.c @@ -30,6 +30,75 @@ static struct device *next_device(struct klist_iter *i) return dev; }
+/** + * driver_set_override() - Helper to set or clear driver override. + * @dev: Device to change + * @override: Address of string to change (e.g. &device->driver_override); + * The contents will be freed and hold newly allocated override. + * @s: NUL-terminated string, new driver name to force a match, pass empty + * string to clear it ("" or "\n", where the latter is only for sysfs + * interface). + * @len: length of @s + * + * Helper to set or clear driver override in a device, intended for the cases + * when the driver_override field is allocated by driver/bus code. + * + * Returns: 0 on success or a negative error code on failure. + */ +int driver_set_override(struct device *dev, const char **override, + const char *s, size_t len) +{ + const char *new, *old; + char *cp; + + if (!override || !s) + return -EINVAL; + + /* + * The stored value will be used in sysfs show callback (sysfs_emit()), + * which has a length limit of PAGE_SIZE and adds a trailing newline. + * Thus we can store one character less to avoid truncation during sysfs + * show. + */ + if (len >= (PAGE_SIZE - 1)) + return -EINVAL; + + if (!len) { + /* Empty string passed - clear override */ + device_lock(dev); + old = *override; + *override = NULL; + device_unlock(dev); + kfree(old); + + return 0; + } + + cp = strnchr(s, len, '\n'); + if (cp) + len = cp - s; + + new = kstrndup(s, len, GFP_KERNEL); + if (!new) + return -ENOMEM; + + device_lock(dev); + old = *override; + if (cp != s) { + *override = new; + } else { + /* "\n" passed - clear override */ + kfree(new); + *override = NULL; + } + device_unlock(dev); + + kfree(old); + + return 0; +} +EXPORT_SYMBOL_GPL(driver_set_override); + /** * driver_for_each_device - Iterator for devices bound to a driver. * @drv: Driver we're iterating. diff --git a/drivers/base/platform.c b/drivers/base/platform.c index 8cc272fd5c99..b684157b7f2f 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -1275,31 +1275,11 @@ static ssize_t driver_override_store(struct device *dev, const char *buf, size_t count) { struct platform_device *pdev = to_platform_device(dev); - char *driver_override, *old, *cp; - - /* We need to keep extra room for a newline */ - if (count >= (PAGE_SIZE - 1)) - return -EINVAL; - - driver_override = kstrndup(buf, count, GFP_KERNEL); - if (!driver_override) - return -ENOMEM; - - cp = strchr(driver_override, '\n'); - if (cp) - *cp = '\0'; - - device_lock(dev); - old = pdev->driver_override; - if (strlen(driver_override)) { - pdev->driver_override = driver_override; - } else { - kfree(driver_override); - pdev->driver_override = NULL; - } - device_unlock(dev); + int ret;
- kfree(old); + ret = driver_set_override(dev, &pdev->driver_override, buf, count); + if (ret) + return ret;
return count; } diff --git a/include/linux/device/driver.h b/include/linux/device/driver.h index 15e7c5e15d62..700453017e1c 100644 --- a/include/linux/device/driver.h +++ b/include/linux/device/driver.h @@ -151,6 +151,8 @@ extern int __must_check driver_create_file(struct device_driver *driver, extern void driver_remove_file(struct device_driver *driver, const struct driver_attribute *attr);
+int driver_set_override(struct device *dev, const char **override, + const char *s, size_t len); extern int __must_check driver_for_each_device(struct device_driver *drv, struct device *start, void *data, diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h index 7c96f169d274..582d83ed9a91 100644 --- a/include/linux/platform_device.h +++ b/include/linux/platform_device.h @@ -31,7 +31,11 @@ struct platform_device { struct resource *resource;
const struct platform_device_id *id_entry; - char *driver_override; /* Driver name to force a match */ + /* + * Driver name to force a match. Do not set directly, because core + * frees it. Use driver_set_override() to set or clear it. + */ + const char *driver_override;
/* MFD cell pointer */ struct mfd_cell *mfd_cell;
On Tue, Apr 19, 2022 at 1:34 PM Krzysztof Kozlowski krzysztof.kozlowski@linaro.org wrote:
Several core drivers and buses expect that driver_override is a dynamically allocated memory thus later they can kfree() it.
However such assumption is not documented, there were in the past and there are already users setting it to a string literal. This leads to kfree() of static memory during device release (e.g. in error paths or during unbind):
kernel BUG at ../mm/slub.c:3960! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM ... (kfree) from [<c058da50>] (platform_device_release+0x88/0xb4) (platform_device_release) from [<c0585be0>] (device_release+0x2c/0x90) (device_release) from [<c0a69050>] (kobject_put+0xec/0x20c) (kobject_put) from [<c0f2f120>] (exynos5_clk_probe+0x154/0x18c) (exynos5_clk_probe) from [<c058de70>] (platform_drv_probe+0x6c/0xa4) (platform_drv_probe) from [<c058b7ac>] (really_probe+0x280/0x414) (really_probe) from [<c058baf4>] (driver_probe_device+0x78/0x1c4) (driver_probe_device) from [<c0589854>] (bus_for_each_drv+0x74/0xb8) (bus_for_each_drv) from [<c058b48c>] (__device_attach+0xd4/0x16c) (__device_attach) from [<c058a638>] (bus_probe_device+0x88/0x90) (bus_probe_device) from [<c05871fc>] (device_add+0x3dc/0x62c) (device_add) from [<c075ff10>] (of_platform_device_create_pdata+0x94/0xbc) (of_platform_device_create_pdata) from [<c07600ec>] (of_platform_bus_create+0x1a8/0x4fc) (of_platform_bus_create) from [<c0760150>] (of_platform_bus_create+0x20c/0x4fc) (of_platform_bus_create) from [<c07605f0>] (of_platform_populate+0x84/0x118) (of_platform_populate) from [<c0f3c964>] (of_platform_default_populate_init+0xa0/0xb8) (of_platform_default_populate_init) from [<c01031f8>] (do_one_initcall+0x8c/0x404)Provide a helper which clearly documents the usage of driver_override. This will allow later to reuse the helper and reduce the amount of duplicated code.
Convert the platform driver to use a new helper and make the driver_override field const char (it is not modified by the core).
Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org
drivers/base/driver.c | 69 +++++++++++++++++++++++++++++++++ drivers/base/platform.c | 28 ++----------- include/linux/device/driver.h | 2 + include/linux/platform_device.h | 6 ++- 4 files changed, 80 insertions(+), 25 deletions(-)
diff --git a/drivers/base/driver.c b/drivers/base/driver.c index 8c0d33e182fd..1b9d47b10bd0 100644 --- a/drivers/base/driver.c +++ b/drivers/base/driver.c @@ -30,6 +30,75 @@ static struct device *next_device(struct klist_iter *i) return dev; }
+/**
- driver_set_override() - Helper to set or clear driver override.
- @dev: Device to change
- @override: Address of string to change (e.g. &device->driver_override);
The contents will be freed and hold newly allocated override.
I would stick to one-line description here and possibly expand them in the body of the comment.
Regardless, I think that the series is an improvement, so please feel free to add
Reviewed-by: Rafael J. Wysocki rafael.j.wysocki@intel.com
to this patch and
Acked-by: Rafael J. Wysocki rafael.j.wysocki@intel.com
to the other patches in the series.
- @s: NUL-terminated string, new driver name to force a match, pass empty
string to clear it ("" or "\n", where the latter is only for sysfs
interface).
- @len: length of @s
- Helper to set or clear driver override in a device, intended for the cases
- when the driver_override field is allocated by driver/bus code.
- Returns: 0 on success or a negative error code on failure.
- */
+int driver_set_override(struct device *dev, const char **override,
const char *s, size_t len)+{
const char *new, *old;char *cp;if (!override || !s)return -EINVAL;/** The stored value will be used in sysfs show callback (sysfs_emit()),* which has a length limit of PAGE_SIZE and adds a trailing newline.* Thus we can store one character less to avoid truncation during sysfs* show.*/if (len >= (PAGE_SIZE - 1))return -EINVAL;if (!len) {/* Empty string passed - clear override */device_lock(dev);old = *override;*override = NULL;device_unlock(dev);kfree(old);return 0;}cp = strnchr(s, len, '\n');if (cp)len = cp - s;new = kstrndup(s, len, GFP_KERNEL);if (!new)return -ENOMEM;device_lock(dev);old = *override;if (cp != s) {*override = new;} else {/* "\n" passed - clear override */kfree(new);*override = NULL;}device_unlock(dev);kfree(old);return 0;+} +EXPORT_SYMBOL_GPL(driver_set_override);
/**
- driver_for_each_device - Iterator for devices bound to a driver.
- @drv: Driver we're iterating.
diff --git a/drivers/base/platform.c b/drivers/base/platform.c index 8cc272fd5c99..b684157b7f2f 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -1275,31 +1275,11 @@ static ssize_t driver_override_store(struct device *dev, const char *buf, size_t count) { struct platform_device *pdev = to_platform_device(dev);
char *driver_override, *old, *cp;/* We need to keep extra room for a newline */if (count >= (PAGE_SIZE - 1))return -EINVAL;driver_override = kstrndup(buf, count, GFP_KERNEL);if (!driver_override)return -ENOMEM;cp = strchr(driver_override, '\n');if (cp)*cp = '\0';device_lock(dev);old = pdev->driver_override;if (strlen(driver_override)) {pdev->driver_override = driver_override;} else {kfree(driver_override);pdev->driver_override = NULL;}device_unlock(dev);
int ret;
kfree(old);
ret = driver_set_override(dev, &pdev->driver_override, buf, count);if (ret)return ret; return count;} diff --git a/include/linux/device/driver.h b/include/linux/device/driver.h index 15e7c5e15d62..700453017e1c 100644 --- a/include/linux/device/driver.h +++ b/include/linux/device/driver.h @@ -151,6 +151,8 @@ extern int __must_check driver_create_file(struct device_driver *driver, extern void driver_remove_file(struct device_driver *driver, const struct driver_attribute *attr);
+int driver_set_override(struct device *dev, const char **override,
const char *s, size_t len);extern int __must_check driver_for_each_device(struct device_driver *drv, struct device *start, void *data, diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h index 7c96f169d274..582d83ed9a91 100644 --- a/include/linux/platform_device.h +++ b/include/linux/platform_device.h @@ -31,7 +31,11 @@ struct platform_device { struct resource *resource;
const struct platform_device_id *id_entry;
char *driver_override; /* Driver name to force a match */
/** Driver name to force a match. Do not set directly, because core* frees it. Use driver_set_override() to set or clear it.*/const char *driver_override; /* MFD cell pointer */ struct mfd_cell *mfd_cell;-- 2.32.0
Use a helper to set driver_override to reduce the amount of duplicated code. Make the driver_override field const char, because it is not modified by the core and it matches other subsystems.
Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org --- drivers/amba/bus.c | 28 ++++------------------------ include/linux/amba/bus.h | 6 +++++- 2 files changed, 9 insertions(+), 25 deletions(-)
diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c index d3bd14aaabf6..f3d26d698b77 100644 --- a/drivers/amba/bus.c +++ b/drivers/amba/bus.c @@ -94,31 +94,11 @@ static ssize_t driver_override_store(struct device *_dev, const char *buf, size_t count) { struct amba_device *dev = to_amba_device(_dev); - char *driver_override, *old, *cp; - - /* We need to keep extra room for a newline */ - if (count >= (PAGE_SIZE - 1)) - return -EINVAL; - - driver_override = kstrndup(buf, count, GFP_KERNEL); - if (!driver_override) - return -ENOMEM; - - cp = strchr(driver_override, '\n'); - if (cp) - *cp = '\0'; - - device_lock(_dev); - old = dev->driver_override; - if (strlen(driver_override)) { - dev->driver_override = driver_override; - } else { - kfree(driver_override); - dev->driver_override = NULL; - } - device_unlock(_dev); + int ret;
- kfree(old); + ret = driver_set_override(_dev, &dev->driver_override, buf, count); + if (ret) + return ret;
return count; } diff --git a/include/linux/amba/bus.h b/include/linux/amba/bus.h index 6562f543c3e0..93799a72ff82 100644 --- a/include/linux/amba/bus.h +++ b/include/linux/amba/bus.h @@ -70,7 +70,11 @@ struct amba_device { unsigned int cid; struct amba_cs_uci_id uci; unsigned int irq[AMBA_NR_IRQS]; - char *driver_override; + /* + * Driver name to force a match. Do not set directly, because core + * frees it. Use driver_set_override() to set or clear it. + */ + const char *driver_override; };
struct amba_driver {
Use a helper to set driver_override to reduce the amount of duplicated code. Make the driver_override field const char, because it is not modified by the core and it matches other subsystems.
Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org --- drivers/bus/fsl-mc/fsl-mc-bus.c | 25 ++++--------------------- include/linux/fsl/mc.h | 6 ++++-- 2 files changed, 8 insertions(+), 23 deletions(-)
diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c index 8fd4a356a86e..ba01c7f4de92 100644 --- a/drivers/bus/fsl-mc/fsl-mc-bus.c +++ b/drivers/bus/fsl-mc/fsl-mc-bus.c @@ -166,31 +166,14 @@ static ssize_t driver_override_store(struct device *dev, const char *buf, size_t count) { struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev); - char *driver_override, *old = mc_dev->driver_override; - char *cp; + int ret;
if (WARN_ON(dev->bus != &fsl_mc_bus_type)) return -EINVAL;
- if (count >= (PAGE_SIZE - 1)) - return -EINVAL; - - driver_override = kstrndup(buf, count, GFP_KERNEL); - if (!driver_override) - return -ENOMEM; - - cp = strchr(driver_override, '\n'); - if (cp) - *cp = '\0'; - - if (strlen(driver_override)) { - mc_dev->driver_override = driver_override; - } else { - kfree(driver_override); - mc_dev->driver_override = NULL; - } - - kfree(old); + ret = driver_set_override(dev, &mc_dev->driver_override, buf, count); + if (ret) + return ret;
return count; } diff --git a/include/linux/fsl/mc.h b/include/linux/fsl/mc.h index 7b6c42bfb660..7a87ab9eba99 100644 --- a/include/linux/fsl/mc.h +++ b/include/linux/fsl/mc.h @@ -170,7 +170,9 @@ struct fsl_mc_obj_desc { * @regions: pointer to array of MMIO region entries * @irqs: pointer to array of pointers to interrupts allocated to this device * @resource: generic resource associated with this MC object device, if any. - * @driver_override: driver name to force a match + * @driver_override: driver name to force a match; do not set directly, + * because core frees it; use driver_set_override() to + * set or clear it. * * Generic device object for MC object devices that are "attached" to a * MC bus. @@ -204,7 +206,7 @@ struct fsl_mc_device { struct fsl_mc_device_irq **irqs; struct fsl_mc_resource *resource; struct device_link *consumer_link; - char *driver_override; + const char *driver_override; };
#define to_fsl_mc_device(_dev) \
Use a helper to set driver_override to the reduce amount of duplicated code. Make the driver_override field const char, because it is not modified by the core and it matches other subsystems.
Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org Reviewed-by: Michael Kelley mikelley@microsoft.com --- drivers/hv/vmbus_drv.c | 28 ++++------------------------ include/linux/hyperv.h | 6 +++++- 2 files changed, 9 insertions(+), 25 deletions(-)
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 14de17087864..607e40aba18e 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -575,31 +575,11 @@ static ssize_t driver_override_store(struct device *dev, const char *buf, size_t count) { struct hv_device *hv_dev = device_to_hv_device(dev); - char *driver_override, *old, *cp; - - /* We need to keep extra room for a newline */ - if (count >= (PAGE_SIZE - 1)) - return -EINVAL; - - driver_override = kstrndup(buf, count, GFP_KERNEL); - if (!driver_override) - return -ENOMEM; - - cp = strchr(driver_override, '\n'); - if (cp) - *cp = '\0'; - - device_lock(dev); - old = hv_dev->driver_override; - if (strlen(driver_override)) { - hv_dev->driver_override = driver_override; - } else { - kfree(driver_override); - hv_dev->driver_override = NULL; - } - device_unlock(dev); + int ret;
- kfree(old); + ret = driver_set_override(dev, &hv_dev->driver_override, buf, count); + if (ret) + return ret;
return count; } diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index fe2e0179ed51..12e2336b23b7 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -1257,7 +1257,11 @@ struct hv_device { u16 device_id;
struct device device; - char *driver_override; /* Driver name to force a match */ + /* + * Driver name to force a match. Do not set directly, because core + * frees it. Use driver_set_override() to set or clear it. + */ + const char *driver_override;
struct vmbus_channel *channel; struct kset *channels_kset;
Use a helper to set driver_override to the reduce amount of duplicated code. Make the driver_override field const char, because it is not modified by the core and it matches other subsystems.
Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org Acked-by: Bjorn Helgaas bhelgaas@google.com Reviewed-by: Andy Shevchenko andy.shevchenko@gmail.com --- drivers/pci/pci-sysfs.c | 28 ++++------------------------ include/linux/pci.h | 6 +++++- 2 files changed, 9 insertions(+), 25 deletions(-)
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index c263ffc5884a..fc804e08e3cb 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -567,31 +567,11 @@ static ssize_t driver_override_store(struct device *dev, const char *buf, size_t count) { struct pci_dev *pdev = to_pci_dev(dev); - char *driver_override, *old, *cp; - - /* We need to keep extra room for a newline */ - if (count >= (PAGE_SIZE - 1)) - return -EINVAL; - - driver_override = kstrndup(buf, count, GFP_KERNEL); - if (!driver_override) - return -ENOMEM; - - cp = strchr(driver_override, '\n'); - if (cp) - *cp = '\0'; - - device_lock(dev); - old = pdev->driver_override; - if (strlen(driver_override)) { - pdev->driver_override = driver_override; - } else { - kfree(driver_override); - pdev->driver_override = NULL; - } - device_unlock(dev); + int ret;
- kfree(old); + ret = driver_set_override(dev, &pdev->driver_override, buf, count); + if (ret) + return ret;
return count; } diff --git a/include/linux/pci.h b/include/linux/pci.h index 60adf42460ab..844d38f589cf 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -516,7 +516,11 @@ struct pci_dev { u16 acs_cap; /* ACS Capability offset */ phys_addr_t rom; /* Physical address if not from BAR */ size_t romlen; /* Length if not from BAR */ - char *driver_override; /* Driver name to force a match */ + /* + * Driver name to force a match. Do not set directly, because core + * frees it. Use driver_set_override() to set or clear it. + */ + const char *driver_override;
unsigned long priv_flags; /* Private flags for the PCI driver */
Use a helper to set driver_override to the reduce amount of duplicated code. Make the driver_override field const char, because it is not modified by the core and it matches other subsystems.
Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org Acked-by: Vineeth Vijayan vneethv@linux.ibm.com --- drivers/s390/cio/cio.h | 6 +++++- drivers/s390/cio/css.c | 28 ++++------------------------ 2 files changed, 9 insertions(+), 25 deletions(-)
diff --git a/drivers/s390/cio/cio.h b/drivers/s390/cio/cio.h index 1cb9daf9c645..fa8df50bb49e 100644 --- a/drivers/s390/cio/cio.h +++ b/drivers/s390/cio/cio.h @@ -103,7 +103,11 @@ struct subchannel { struct work_struct todo_work; struct schib_config config; u64 dma_mask; - char *driver_override; /* Driver name to force a match */ + /* + * Driver name to force a match. Do not set directly, because core + * frees it. Use driver_set_override() to set or clear it. + */ + const char *driver_override; } __attribute__ ((aligned(8)));
DECLARE_PER_CPU_ALIGNED(struct irb, cio_irb); diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c index fa8293335077..913b6ddd040b 100644 --- a/drivers/s390/cio/css.c +++ b/drivers/s390/cio/css.c @@ -338,31 +338,11 @@ static ssize_t driver_override_store(struct device *dev, const char *buf, size_t count) { struct subchannel *sch = to_subchannel(dev); - char *driver_override, *old, *cp; - - /* We need to keep extra room for a newline */ - if (count >= (PAGE_SIZE - 1)) - return -EINVAL; - - driver_override = kstrndup(buf, count, GFP_KERNEL); - if (!driver_override) - return -ENOMEM; - - cp = strchr(driver_override, '\n'); - if (cp) - *cp = '\0'; - - device_lock(dev); - old = sch->driver_override; - if (strlen(driver_override)) { - sch->driver_override = driver_override; - } else { - kfree(driver_override); - sch->driver_override = NULL; - } - device_unlock(dev); + int ret;
- kfree(old); + ret = driver_set_override(dev, &sch->driver_override, buf, count); + if (ret) + return ret;
return count; }
Use a helper to set driver_override to the reduce amount of duplicated code.
Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org Reviewed-by: Mark Brown broonie@kernel.org --- drivers/spi/spi.c | 26 ++++---------------------- include/linux/spi/spi.h | 2 ++ 2 files changed, 6 insertions(+), 22 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 890ff46c784a..be8f1a1e21b2 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -71,29 +71,11 @@ static ssize_t driver_override_store(struct device *dev, const char *buf, size_t count) { struct spi_device *spi = to_spi_device(dev); - const char *end = memchr(buf, '\n', count); - const size_t len = end ? end - buf : count; - const char *driver_override, *old; - - /* We need to keep extra room for a newline when displaying value */ - if (len >= (PAGE_SIZE - 1)) - return -EINVAL; - - driver_override = kstrndup(buf, len, GFP_KERNEL); - if (!driver_override) - return -ENOMEM; + int ret;
- device_lock(dev); - old = spi->driver_override; - if (len) { - spi->driver_override = driver_override; - } else { - /* Empty string, disable driver override */ - spi->driver_override = NULL; - kfree(driver_override); - } - device_unlock(dev); - kfree(old); + ret = driver_set_override(dev, &spi->driver_override, buf, count); + if (ret) + return ret;
return count; } diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 5f8c063ddff4..f0177f9b6e13 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -138,6 +138,8 @@ extern int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer); * for driver coldplugging, and in uevents used for hotplugging * @driver_override: If the name of a driver is written to this attribute, then * the device will bind to the named driver and only the named driver. + * Do not set directly, because core frees it; use driver_set_override() to + * set or clear it. * @cs_gpiod: gpio descriptor of the chipselect line (optional, NULL when * not using a GPIO line) * @word_delay: delay to be inserted between consecutive
Use a helper to set driver_override to the reduce amount of duplicated code.
Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org Acked-by: Michael S. Tsirkin mst@redhat.com --- drivers/vdpa/vdpa.c | 29 ++++------------------------- include/linux/vdpa.h | 4 +++- 2 files changed, 7 insertions(+), 26 deletions(-)
diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c index 2b75c00b1005..33d1ad60cba7 100644 --- a/drivers/vdpa/vdpa.c +++ b/drivers/vdpa/vdpa.c @@ -77,32 +77,11 @@ static ssize_t driver_override_store(struct device *dev, const char *buf, size_t count) { struct vdpa_device *vdev = dev_to_vdpa(dev); - const char *driver_override, *old; - char *cp; + int ret;
- /* We need to keep extra room for a newline */ - if (count >= (PAGE_SIZE - 1)) - return -EINVAL; - - driver_override = kstrndup(buf, count, GFP_KERNEL); - if (!driver_override) - return -ENOMEM; - - cp = strchr(driver_override, '\n'); - if (cp) - *cp = '\0'; - - device_lock(dev); - old = vdev->driver_override; - if (strlen(driver_override)) { - vdev->driver_override = driver_override; - } else { - kfree(driver_override); - vdev->driver_override = NULL; - } - device_unlock(dev); - - kfree(old); + ret = driver_set_override(dev, &vdev->driver_override, buf, count); + if (ret) + return ret;
return count; } diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h index 8943a209202e..c0a5083632ab 100644 --- a/include/linux/vdpa.h +++ b/include/linux/vdpa.h @@ -64,7 +64,9 @@ struct vdpa_mgmt_dev; * struct vdpa_device - representation of a vDPA device * @dev: underlying device * @dma_dev: the actual device that is performing DMA - * @driver_override: driver name to force a match + * @driver_override: driver name to force a match; do not set directly, + * because core frees it; use driver_set_override() to + * set or clear it. * @config: the configuration ops for this device. * @cf_mutex: Protects get and set access to configuration layout. * @index: device index
The driver_override field from platform driver should not be initialized from static memory (string literal) because the core later kfree() it, for example when driver_override is set via sysfs.
Use dedicated helper to set driver_override properly.
Fixes: 77d8f3068c63 ("clk: imx: scu: add two cells binding support") Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org Acked-by: Stephen Boyd sboyd@kernel.org --- drivers/clk/imx/clk-scu.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/imx/clk-scu.c b/drivers/clk/imx/clk-scu.c index ed3c01d2e8ae..4996f1d94657 100644 --- a/drivers/clk/imx/clk-scu.c +++ b/drivers/clk/imx/clk-scu.c @@ -683,7 +683,12 @@ struct clk_hw *imx_clk_scu_alloc_dev(const char *name, return ERR_PTR(ret); }
- pdev->driver_override = "imx-scu-clk"; + ret = driver_set_override(&pdev->dev, &pdev->driver_override, + "imx-scu-clk", strlen("imx-scu-clk")); + if (ret) { + platform_device_put(pdev); + return ERR_PTR(ret); + }
ret = imx_clk_scu_attach_pd(&pdev->dev, rsrc_id); if (ret)
On 22-04-19 13:34:32, Krzysztof Kozlowski wrote:
The driver_override field from platform driver should not be initialized from static memory (string literal) because the core later kfree() it, for example when driver_override is set via sysfs.
Use dedicated helper to set driver_override properly.
Fixes: 77d8f3068c63 ("clk: imx: scu: add two cells binding support") Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org Acked-by: Stephen Boyd sboyd@kernel.org
Reviewed-by: Abel Vesa abel.vesa@nxp.com
drivers/clk/imx/clk-scu.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/imx/clk-scu.c b/drivers/clk/imx/clk-scu.c index ed3c01d2e8ae..4996f1d94657 100644 --- a/drivers/clk/imx/clk-scu.c +++ b/drivers/clk/imx/clk-scu.c @@ -683,7 +683,12 @@ struct clk_hw *imx_clk_scu_alloc_dev(const char *name, return ERR_PTR(ret); }
- pdev->driver_override = "imx-scu-clk";
ret = driver_set_override(&pdev->dev, &pdev->driver_override,
"imx-scu-clk", strlen("imx-scu-clk"));if (ret) {
platform_device_put(pdev);return ERR_PTR(ret);}
ret = imx_clk_scu_attach_pd(&pdev->dev, rsrc_id); if (ret)
-- 2.32.0
The driver_override field from platform driver should not be initialized from static memory (string literal) because the core later kfree() it, for example when driver_override is set via sysfs.
Use dedicated helper to set driver_override properly.
Fixes: 917809e2280b ("slimbus: ngd: Add qcom SLIMBus NGD driver") Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org Reviewed-by: Srinivas Kandagatla srinivas.kandagatla@linaro.org --- drivers/slimbus/qcom-ngd-ctrl.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/slimbus/qcom-ngd-ctrl.c b/drivers/slimbus/qcom-ngd-ctrl.c index 0f29a08b4c09..0aa8408464ad 100644 --- a/drivers/slimbus/qcom-ngd-ctrl.c +++ b/drivers/slimbus/qcom-ngd-ctrl.c @@ -1434,6 +1434,7 @@ static int of_qcom_slim_ngd_register(struct device *parent, const struct of_device_id *match; struct device_node *node; u32 id; + int ret;
match = of_match_node(qcom_slim_ngd_dt_match, parent->of_node); data = match->data; @@ -1455,7 +1456,17 @@ static int of_qcom_slim_ngd_register(struct device *parent, } ngd->id = id; ngd->pdev->dev.parent = parent; - ngd->pdev->driver_override = QCOM_SLIM_NGD_DRV_NAME; + + ret = driver_set_override(&ngd->pdev->dev, + &ngd->pdev->driver_override, + QCOM_SLIM_NGD_DRV_NAME, + strlen(QCOM_SLIM_NGD_DRV_NAME)); + if (ret) { + platform_device_put(ngd->pdev); + kfree(ngd); + of_node_put(node); + return ret; + } ngd->pdev->dev.of_node = node; ctrl->ngd = ngd;
Memory pointed by variable 'old' in field store macro is not modified, so it can be made a pointer to const.
Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org --- drivers/rpmsg/rpmsg_core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c index 79368a957d89..95fc283f6af7 100644 --- a/drivers/rpmsg/rpmsg_core.c +++ b/drivers/rpmsg/rpmsg_core.c @@ -400,7 +400,8 @@ field##_store(struct device *dev, struct device_attribute *attr, \ const char *buf, size_t sz) \ { \ struct rpmsg_device *rpdev = to_rpmsg_device(dev); \ - char *new, *old; \ + const char *old; \ + char *new; \ \ new = kstrndup(buf, sz, GFP_KERNEL); \ if (!new) \
The driver_override field from platform driver should not be initialized from static memory (string literal) because the core later kfree() it, for example when driver_override is set via sysfs.
Use dedicated helper to set driver_override properly.
Fixes: 950a7388f02b ("rpmsg: Turn name service into a stand alone driver") Fixes: c0cdc19f84a4 ("rpmsg: Driver for user space endpoint interface") Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org Reviewed-by: Bjorn Andersson bjorn.andersson@linaro.org --- drivers/rpmsg/rpmsg_internal.h | 13 +++++++++++-- drivers/rpmsg/rpmsg_ns.c | 14 ++++++++++++-- include/linux/rpmsg.h | 6 ++++-- 3 files changed, 27 insertions(+), 6 deletions(-)
diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h index d4b23fd019a8..3e81642238d2 100644 --- a/drivers/rpmsg/rpmsg_internal.h +++ b/drivers/rpmsg/rpmsg_internal.h @@ -94,10 +94,19 @@ int rpmsg_release_channel(struct rpmsg_device *rpdev, */ static inline int rpmsg_ctrldev_register_device(struct rpmsg_device *rpdev) { + int ret; + strcpy(rpdev->id.name, "rpmsg_ctrl"); - rpdev->driver_override = "rpmsg_ctrl"; + ret = driver_set_override(&rpdev->dev, &rpdev->driver_override, + rpdev->id.name, strlen(rpdev->id.name)); + if (ret) + return ret; + + ret = rpmsg_register_device(rpdev); + if (ret) + kfree(rpdev->driver_override);
- return rpmsg_register_device(rpdev); + return ret; }
#endif diff --git a/drivers/rpmsg/rpmsg_ns.c b/drivers/rpmsg/rpmsg_ns.c index 762ff1ae279f..8eb8f328237e 100644 --- a/drivers/rpmsg/rpmsg_ns.c +++ b/drivers/rpmsg/rpmsg_ns.c @@ -20,12 +20,22 @@ */ int rpmsg_ns_register_device(struct rpmsg_device *rpdev) { + int ret; + strcpy(rpdev->id.name, "rpmsg_ns"); - rpdev->driver_override = "rpmsg_ns"; + ret = driver_set_override(&rpdev->dev, &rpdev->driver_override, + rpdev->id.name, strlen(rpdev->id.name)); + if (ret) + return ret; + rpdev->src = RPMSG_NS_ADDR; rpdev->dst = RPMSG_NS_ADDR;
- return rpmsg_register_device(rpdev); + ret = rpmsg_register_device(rpdev); + if (ret) + kfree(rpdev->driver_override); + + return ret; } EXPORT_SYMBOL(rpmsg_ns_register_device);
diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h index 02fa9116cd60..20c8cd1cde21 100644 --- a/include/linux/rpmsg.h +++ b/include/linux/rpmsg.h @@ -41,7 +41,9 @@ struct rpmsg_channel_info { * rpmsg_device - device that belong to the rpmsg bus * @dev: the device struct * @id: device id (used to match between rpmsg drivers and devices) - * @driver_override: driver name to force a match + * @driver_override: driver name to force a match; do not set directly, + * because core frees it; use driver_set_override() to + * set or clear it. * @src: local address * @dst: destination address * @ept: the rpmsg endpoint of this channel @@ -51,7 +53,7 @@ struct rpmsg_channel_info { struct rpmsg_device { struct device dev; struct rpmsg_device_id id; - char *driver_override; + const char *driver_override; u32 src; u32 dst; struct rpmsg_endpoint *ept;
On 19/04/2022 13:34, Krzysztof Kozlowski wrote:
Hi Greg, Rafael,
The patchset was for some time on the lists, got some reviews, some changes/feedback which I hope I applied/responded.
Entire set depends on the driver core changes, so maybe you could pick up everything via drivers core tree?
Dependencies (and stable):
- All patches, including last three fixes, depend on the first patch introducing the helper.
- The last three commits - fixes - are probably not backportable directly, because of this dependency. I don't know how to express this dependency here, since stable-kernel-rules.rst mentions only commits as possible dependencies.
Best regards, Krzysztof
On Wed, Apr 20, 2022 at 11:20:06AM +0200, Krzysztof Kozlowski wrote:
On 19/04/2022 13:34, Krzysztof Kozlowski wrote:
Hi Greg, Rafael,
The patchset was for some time on the lists, got some reviews, some changes/feedback which I hope I applied/responded.
Entire set depends on the driver core changes, so maybe you could pick up everything via drivers core tree?
Ok, will do, thanks.
greg k-h
participants (4)
-
Abel Vesa -
Greg Kroah-Hartman -
Krzysztof Kozlowski -
Rafael J. Wysocki