kernel/linux.git/drivers/counter/counter-core.c, branch v7.1

counter: Fix refcount leak in counter_alloc() error path

2026-05-03T04:48:39+00:00

After device_initialize(), the lifetime of the embedded struct device is expected to be managed through the device core reference counting. In counter_alloc(), if dev_set_name() fails after device_initialize(), the error path removes the chrdev, frees the ID, and frees the backing allocation directly instead of releasing the device reference with put_device(). This bypasses the normal device lifetime rules and may leave the reference count of the embedded struct device unbalanced, resulting in a refcount leak. The issue was identified by a static analysis tool I developed and confirmed by manual review. Fix this by using put_device() in the dev_set_name() failure path and let counter_device_release() handle the final cleanup. Fixes: 4da08477ea1f ("counter: Set counter device name") Cc: stable@vger.kernel.org Signed-off-by: Guangshuo Li Link: https://lore.kernel.org/r/20260413134604.2861772-1-lgs201920130244@gmail.com Signed-off-by: William Breathitt Gray

module: Convert symbol namespace to string literal

2024-12-02T19:34:44+00:00

Clean up the existing export namespace code along the same lines of commit 33def8498fdd ("treewide: Convert macro and uses of __section(foo) to __section("foo")") and for the same reason, it is not desired for the namespace argument to be a macro expansion itself. Scripted using git grep -l -e MODULE_IMPORT_NS -e EXPORT_SYMBOL_NS | while read file; do awk -i inplace ' /^#define EXPORT_SYMBOL_NS/ { gsub(/__stringify$ns$/, "ns"); print; next; } /^#define MODULE_IMPORT_NS/ { gsub(/__stringify$ns$/, "ns"); print; next; } /MODULE_IMPORT_NS/ { $0 = gensub(/MODULE_IMPORT_NS$([^)]*)$/, "MODULE_IMPORT_NS(\"\\1\")", "g"); } /EXPORT_SYMBOL_NS/ { if ($0 ~ /(EXPORT_SYMBOL_NS[^(]*)$([^,]+),/) { if ($0 !~ /(EXPORT_SYMBOL_NS[^(]*)\(([^,]+), ([^)]+)$/ && $0 !~ /(EXPORT_SYMBOL_NS[^(]*)/ && $0 !~ /^my/) { getline line; gsub(/[[:space:]]*\\$/, ""); gsub(/[[:space:]]/, "", line); $0 = $0 " " line; } $0 = gensub(/(EXPORT_SYMBOL_NS[^(]*)$([^,]+), ([^)]+)$/, "\\1(\\2, \"\\3\")", "g"); } } { print }' $file; done Requested-by: Masahiro Yamada Signed-off-by: Peter Zijlstra (Intel) Link: https://mail.google.com/mail/u/2/#inbox/FMfcgzQXKWgMmjdFwwdsfgxzKpVHWPlc Acked-by: Greg KH Signed-off-by: Linus Torvalds

counter: constify the struct device_type usage

2024-04-02T17:10:34+00:00

Since commit aed65af1cc2f ("drivers: make device_type const"), the driver core can properly handle constant struct device_type. Move the counter_device_type variable to be a constant structure as well, placing it into read-only memory which can not be modified at runtime. Cc: Greg Kroah-Hartman Signed-off-by: "Ricardo B. Marliere" Link: https://lore.kernel.org/r/20240219-device_cleanup-counter-v1-1-24d0316ae815@marliere.net Signed-off-by: William Breathitt Gray

counter: make counter_bus_type const

2024-04-02T17:10:33+00:00

Now that the driver core can properly handle constant struct bus_type, move the counter_bus_type variable to be a constant structure as well, placing it into read-only memory which can not be modified at runtime. Suggested-by: Greg Kroah-Hartman Signed-off-by: "Ricardo B. Marliere" Reviewed-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/20240204-bus_cleanup-counter-v1-1-cef9dd719bdc@marliere.net Signed-off-by: William Breathitt Gray

counter: fix privdata alignment

2024-02-16T23:51:00+00:00

Aligning to the L1 cache does not guarantee the same alignment as kmallocing an object [1]. Furthermore, in some platforms, that alignment is not sufficient for DMA safety (in case someone wants to have a DMA safe buffer in privdata) [2]. Sometime ago, we had the same fixes in IIO. [1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/base/devres.c#n35 [2]: https://lore.kernel.org/linux-iio/20220508175712.647246-2-jic23@kernel.org/ Fixes: c18e2760308e ("counter: Provide alternative counter registration functions") Signed-off-by: Nuno Sa Link: https://lore.kernel.org/r/20240209-counter-align-fix-v2-1-5777ea0a2722@analog.com Signed-off-by: William Breathitt Gray

counter: Move symbols into COUNTER namespace

2022-09-30T12:32:35+00:00

Counter subsystem symbols are only relevant to counter drivers. A COUNTER namespace is created to control the availability of these symbols to modules that import this namespace explicitly. Cc: Patrick Havelange Cc: Jarkko Nikula Cc: Oleksij Rempel Cc: Pengutronix Kernel Team Cc: Kamel Bouhara Cc: Fabrice Gasnier Cc: Maxime Coquelin Cc: Alexandre Torgue Acked-by: David Lechner Reviewed-by: Jonathan Cameron Link: https://lore.kernel.org/r/20220815220321.74161-1-william.gray@linaro.org/ Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/8a756df96c24946547a7ece5caa5f654809c5e7f.1664318353.git.william.gray@linaro.org Signed-off-by: Greg Kroah-Hartman

counter: Set counter device name

2022-03-18T13:04:30+00:00

Naming the counter device provides a convenient way to identify it in devres_log events and similar situations. This patch names the counter device by combining the prefix "counter" with the counter device's unique ID. Link: https://lore.kernel.org/r/20220204084551.16397-1-vilhelm.gray@gmail.com Acked-by: Uwe Kleine-König Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/87cc8eb4c84f49f89290577dc9231b2e4d7d3e8c.1647373009.git.vilhelm.gray@gmail.com Signed-off-by: Greg Kroah-Hartman

counter: fix an IS_ERR() vs NULL bug

2022-01-26T18:40:33+00:00

There are 8 callers for devm_counter_alloc() and they all check for NULL instead of error pointers. I think NULL is the better thing to return for allocation functions so update counter_alloc() and devm_counter_alloc() to return NULL instead of error pointers. Fixes: c18e2760308e ("counter: Provide alternative counter registration functions") Acked-by: Uwe Kleine-König Acked-by: William Breathitt Gray Signed-off-by: Dan Carpenter Link: https://lore.kernel.org/r/20220111173243.GA2192@kili Signed-off-by: Greg Kroah-Hartman

counter: remove old and now unused registration API

2021-12-30T16:44:07+00:00

Usage of counter_register() yields issues in device lifetime tracking. All drivers were converted to the new API, so the old one can go away. Reviewed-by: Jonathan Cameron Acked-by: William Breathitt Gray Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20211230150300.72196-24-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman

counter: Provide alternative counter registration functions

2021-12-30T16:44:06+00:00

The current implementation gets device lifetime tracking wrong. The problem is that allocation of struct counter_device is controlled by the individual drivers but this structure contains a struct device that might have to live longer than a driver is bound. As a result a command sequence like: { sleep 5; echo bang; } > /dev/counter0 & sleep 1; echo 40000000.timer:counter > /sys/bus/platform/drivers/stm32-timer-counter/unbind can keep a reference to the struct device and unbinding results in freeing the memory occupied by this device resulting in an oops. This commit provides two new functions (plus some helpers): - counter_alloc() to allocate a struct counter_device that is automatically freed once the embedded struct device is released - counter_add() to register such a device. Note that this commit doesn't fix any issues, all drivers have to be converted to these new functions to correct the lifetime problems. Reviewed-by: Jonathan Cameron Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20211230150300.72196-14-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman