kernel/linux.git/drivers/base/base.h, branch v6.6.132

Revert "driver core: enforce device_lock for driver_match_device()"

2026-02-16T16:08:02+00:00

This reverts commit adc1796eced46b48e23ec200a219d635f33a38ee which is commit dc23806a7c47ec5f1293aba407fb69519f976ee0 upstream. It causes boot regressions on some systems as all of the "fixes" for drivers are not properly backported yet. Once that is completed, only then can this be applied, if really necessary given the potential for explosions, perhaps we might want to wait a few -rc releases first... Cc: Danilo Krummrich Cc: Rafael J. Wysocki (Intel) Cc: Danilo Krummrich Cc: Gui-Dong Han Cc: Qiu-ji Chen Reported-by: Mark Brown Link: https://lore.kernel.org/r/7dfd0e63-a725-4fac-b2a0-f2e621d99d1b@sirena.org.uk Signed-off-by: Greg Kroah-Hartman

driver core: enforce device_lock for driver_match_device()

2026-02-16T09:17:47+00:00

commit dc23806a7c47ec5f1293aba407fb69519f976ee0 upstream. Currently, driver_match_device() is called from three sites. One site (__device_attach_driver) holds device_lock(dev), but the other two (bind_store and __driver_attach) do not. This inconsistency means that bus match() callbacks are not guaranteed to be called with the lock held. Fix this by introducing driver_match_device_locked(), which guarantees holding the device lock using a scoped guard. Replace the unlocked calls in bind_store() and __driver_attach() with this new helper. Also add a lock assertion to driver_match_device() to enforce this guarantee. This consistency also fixes a known race condition. The driver_override implementation relies on the device_lock, so the missing lock led to the use-after-free (UAF) reported in Bugzilla for buses using this field. Stress testing the two newly locked paths for 24 hours with CONFIG_PROVE_LOCKING and CONFIG_LOCKDEP enabled showed no UAF recurrence and no lockdep warnings. Cc: stable@vger.kernel.org Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220789 Suggested-by: Qiu-ji Chen Signed-off-by: Gui-Dong Han Fixes: 49b420a13ff9 ("driver core: check bus->match without holding device lock") Reviewed-by: Danilo Krummrich Reviewed-by: Greg Kroah-Hartman Reviewed-by: Rafael J. Wysocki (Intel) Link: https://patch.msgid.link/20260113162843.12712-1-hanguidong02@gmail.com Signed-off-by: Danilo Krummrich Signed-off-by: Greg Kroah-Hartman

driver core: fix potential NULL pointer dereference in dev_uevent()

2025-05-02T05:51:03+00:00

commit 18daa52418e7e4629ed1703b64777294209d2622 upstream. If userspace reads "uevent" device attribute at the same time as another threads unbinds the device from its driver, change to dev->driver from a valid pointer to NULL may result in crash. Fix this by using READ_ONCE() when fetching the pointer, and take bus' drivers klist lock to make sure driver instance will not disappear while we access it. Use WRITE_ONCE() when setting the driver pointer to ensure there is no tearing. Signed-off-by: Dmitry Torokhov Reviewed-by: Masami Hiramatsu (Google) Link: https://lore.kernel.org/r/20250311052417.1846985-3-dmitry.torokhov@gmail.com Signed-off-by: Greg Kroah-Hartman

driver core: introduce device_set_driver() helper

2025-05-02T05:51:03+00:00

commit 04d3e5461c1f5cf8eec964ab64948ebed826e95e upstream. In preparation to closing a race when reading driver pointer in dev_uevent() code, instead of setting device->driver pointer directly introduce device_set_driver() helper. Signed-off-by: Dmitry Torokhov Reviewed-by: Masami Hiramatsu (Google) Link: https://lore.kernel.org/r/20250311052417.1846985-2-dmitry.torokhov@gmail.com Signed-off-by: Greg Kroah-Hartman

module: don't ignore sysfs_create_link() failures

2024-06-12T09:12:17+00:00

[ Upstream commit 85d2b0aa170351380be39fe4ff7973df1427fe76 ] The sysfs_create_link() return code is marked as __must_check, but the module_add_driver() function tries hard to not care, by assigning the return code to a variable. When building with 'make W=1', gcc still warns because this variable is only assigned but not used: drivers/base/module.c: In function 'module_add_driver': drivers/base/module.c:36:6: warning: variable 'no_warn' set but not used [-Wunused-but-set-variable] Rework the code to properly unwind and return the error code to the caller. My reading of the original code was that it tries to not fail when the links already exist, so keep ignoring -EEXIST errors. Fixes: e17e0f51aeea ("Driver core: show drivers in /sys/module/") See-also: 4a7fb6363f2d ("add __must_check to device management code") Signed-off-by: Arnd Bergmann Reviewed-by: Luis Chamberlain Link: https://lore.kernel.org/r/20240408080616.3911573-1-arnd@kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

driver core: class: make class_register() take a const *

2023-04-03T19:42:46+00:00

Now that the class code is cleaned up to not modify the class pointer registered with it, change class_register() to take a const * to allow the structure to be placed into read-only memory. Acked-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/2023040248-customary-release-4aec@gregkh Signed-off-by: Greg Kroah-Hartman

driver core: make sysfs_dev_char_kobj static

2023-03-31T15:45:18+00:00

Nothing outside of drivers/base/core.c uses sysfs_dev_char_kobj, so make it static and document what it is used for so we remember it the next time we touch it 15 years from now. Acked-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/20230331093318.82288-7-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

driver core: clean up the logic to determine which /sys/dev/ directory to use

2023-03-31T15:45:07+00:00

When a dev_t is set in a struct device, an symlink in /sys/dev/ is created for it either under /sys/dev/block/ or /sys/dev/char/ depending on the device type. The logic to determine this would trigger off of the class of the object, and the kobj_type set in that location. But it turns out that this deep nesting isn't needed at all, as it's either a choice of block or "everything else" which is a char device. So make the logic a lot more simple and obvious, and remove the incorrect comments in the code that tried to document something that was not happening at all (it is impossible to set class->dev_kobj to NULL as the class core prevented that from happening. This removes the only place that class->dev_kobj was being used, so after this, it can be removed entirely. Acked-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/20230331093318.82288-4-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

driver core: core: move to use class_to_subsys()

2023-03-31T13:13:35+00:00

There are a number of places in core.c that need access to the private subsystem structure of struct class, so move them to use class_to_subsys() instead of accessing it directly. This requires exporting class_to_subsys() out of class.c, but keeping it local to the driver core. Reviewed-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/20230331093318.82288-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

driver core: move sysfs_dev_char_kobj out of class.h

2023-03-27T16:24:29+00:00

The structure sysfs_dev_char_kobj is local only to the driver core code, so move it out of the global class.h file and into the internal base.h file as no one else should be touching this symbol. Acked-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/20230327160319.513974-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman