kernel/linux.git/drivers/hwmon, branch v6.18.35

hwmon: (pmbus/adm1266) serialize GPIO PMBus accesses with pmbus_lock

2026-06-09T10:28:52+00:00

[ Upstream commit bab8c6fb5af8df7e753d196c1262cb78e92ca872 ] adm1266_gpio_get(), adm1266_gpio_get_multiple(), and adm1266_gpio_dbg_show() all issue PMBus reads against the device but none of them take pmbus_lock. The pmbus_core framework holds pmbus_lock around its own multi-transaction sequences (notably the "set PAGE, then read paged register" pattern used by hwmon attributes), so an unlocked GPIO accessor can land between a PAGE write and the subsequent paged read in another thread and corrupt either side's view of the device state machine. Take pmbus_lock at the top of each of the three accessors via the scope-based guard(). The lock is uncontended in the common case and adds only a single mutex round-trip per call. Fixes: d98dfad35c38 ("hwmon: (pmbus/adm1266) Add support for GPIOs") Cc: stable@vger.kernel.org Signed-off-by: Abdurrahman Hussain Reviewed-by: Bartosz Golaszewski Link: https://lore.kernel.org/r/20260518-adm1266-gpio-fixes-v3-6-e425e4f88139@nexthop.ai Signed-off-by: Guenter Roeck Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

hwmon: (pmbus/adm1266) serialize sequencer_state debugfs read with pmbus_lock

2026-06-09T10:28:52+00:00

[ Upstream commit 4e4af55aaca7f6d7673d5f9889ad0529db86a048 ] adm1266_state_read() backs the sequencer_state debugfs entry and issues an i2c_smbus_read_word_data(client, ADM1266_READ_STATE) against the device without taking pmbus_lock. pmbus_core holds pmbus_lock around its own multi-transaction sequences (notably the "set PAGE, then read paged register" pattern used by hwmon attributes), so an unlocked debugfs reader can land between a PAGE write and the subsequent paged read in another thread. READ_STATE itself is not paged, so it cannot corrupt PAGE in flight, but the same defensive serialisation that applies to the GPIO accessors applies here: any direct device access from outside pmbus_core should be ordered with respect to pmbus_core's own. Take pmbus_lock at the top of adm1266_state_read() via the scope-based guard(). Fixes: ed1ff457e187 ("hwmon: (pmbus/adm1266) add debugfs for states") Cc: stable@vger.kernel.org Signed-off-by: Abdurrahman Hussain Link: https://lore.kernel.org/r/20260518-adm1266-gpio-fixes-v3-8-e425e4f88139@nexthop.ai Signed-off-by: Guenter Roeck Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

hwmon: (pmbus) Add support for guarded PMBus lock

2026-06-09T10:28:52+00:00

[ Upstream commit 1814f4d3ff358277a5b6957e7f133c2812dc80ec ] Add support for guard(pmbus_lock)() and scoped_guard(pmbus_lock)() to be able to simplify the PMBus code. Also introduce pmbus_lock() as pre-requisite for supporting guard(). Reviewed-by: Sanman Pradhan Signed-off-by: Guenter Roeck Stable-dep-of: 4e4af55aaca7 ("hwmon: (pmbus/adm1266) serialize sequencer_state debugfs read with pmbus_lock") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

hwmon: (lm90) Add lock protection to lm90_alert

2026-06-01T15:51:02+00:00

[ Upstream commit 873e919e3101063a7a75989510ccfc125a4391cf ] Sashiko reports: lm90_alert() executes in the smbus alert context and calls lm90_update_confreg() to disable the hardware alert line, without acquiring hwmon_lock. Concurrently, sysfs write operations (such as lm90_write_convrate) hold the hwmon_lock, temporarily modify data->config, and then restore it. If an alert interrupt occurs concurrently with a sysfs write, the sysfs path will overwrite the alert handler's modifications to data->config and the hardware register. This unintentionally re-enables the hardware alert line while the alarm is still active, causing an interrupt storm. Add the missing lock to lm90_alert() to solve the problem. Fixes: 7a1d220ccb0cc ("hwmon: (lm90) Introduce function to update configuration register") Reported-by: Sashiko Signed-off-by: Guenter Roeck Signed-off-by: Sasha Levin

hwmon: (lm90) Stop work before releasing hwmon device

2026-06-01T15:51:02+00:00

[ Upstream commit b09a45601094c7f4ec4db8090b825fa61e169d93 ] Sashiko reports: In lm90_probe(), the devm action to cancel the alert_work and report_work (lm90_restore_conf) is registered in lm90_init_client() before devm_hwmon_device_register_with_info() is called. Because devm executes cleanup actions in reverse order during module unbind or probe failure, the hwmon device is unregistered and freed first. If lm90_alert_work() or lm90_report_alarms() runs in the window between the hwmon device being freed and the delayed works being cancelled, lm90_update_alarms() will dereference the freed data->hwmon_dev here. Fix the problem by canceling the workers separately after registering the hwmon device and before registering the interrupt handler. This ensures that the workers are canceled after interrupts are disabled and before the hwmon device is released. Add "shutdown" flag to indicate that device shutdown is in progress to prevent workers from being re-armed. Fixes: f6d0775119fb9 ("hwmon: (lm90) Rework alarm/status handling") Reported-by: Sashiko Signed-off-by: Guenter Roeck Signed-off-by: Sasha Levin

hwmon: (pmbus/adm1266) reject short block-read responses in the GPIO accessors

2026-06-01T15:50:51+00:00

commit a7232f68c43ca62f545049b7f5fbfc75137b843b upstream. adm1266_gpio_get() and adm1266_gpio_get_multiple() both compose the pin-status word as pins_status = read_buf[0] + (read_buf[1] << 8); right after i2c_smbus_read_block_data(), guarding only against an error return. A well-behaved device returns 2 bytes for GPIO_STATUS/PDIO_STATUS, but the helper happily reports a 0- or 1-byte response too. If the device returns 0 bytes, both read_buf slots are uninitialized stack memory; if it returns 1 byte, read_buf[1] is. The composed value then flows through set_bit() into the caller's *bits in adm1266_gpio_get_multiple(), or into the return value of adm1266_gpio_get(), and ends up in userspace via gpiolib (sysfs and the char-dev ioctls). That leaks a few bits of kernel stack per request on any device whose firmware glitch, bus error, or hostile slave produces a short block-read response. Add the missing length check to both call sites and surface a short response as -EIO. Fixes: d98dfad35c38 ("hwmon: (pmbus/adm1266) Add support for GPIOs") Cc: stable@vger.kernel.org Signed-off-by: Abdurrahman Hussain Reviewed-by: Bartosz Golaszewski Link: https://lore.kernel.org/r/20260518-adm1266-gpio-fixes-v3-3-e425e4f88139@nexthop.ai Signed-off-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman

hwmon: (pmbus/adm1266) register the nvmem device after pmbus_do_probe()

2026-06-01T15:50:50+00:00

commit 6af713af91d5c34ec049eb3cc2c5b3f5eba953b8 upstream. adm1266_probe() calls adm1266_config_nvmem() -- which goes on to devm_nvmem_register() and exposes adm1266_nvmem_read() to userspace -- before pmbus_do_probe() has initialised the per-client PMBus state. Same latent hazard as the gpio_chip one fixed in the previous patch: once the nvmem device is registered, gpiolib's nvmem char-dev / sysfs interface is reachable, and any concurrent read triggers adm1266_nvmem_read() -> adm1266_nvmem_read_blackbox(), which issues PMBus traffic that races pmbus_do_probe()'s own device accesses with no serialisation. Move adm1266_config_nvmem() down past pmbus_do_probe() so the nvmem device isn't reachable from userspace until the PMBus state the nvmem accessors depend on is fully initialised. Fixes: 15609d189302 ("hwmon: (pmbus/adm1266) read blackbox") Cc: stable@vger.kernel.org Signed-off-by: Abdurrahman Hussain Link: https://lore.kernel.org/r/20260518-adm1266-gpio-fixes-v3-5-e425e4f88139@nexthop.ai Signed-off-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman

hwmon: (pmbus/adm1266) register the gpio_chip after pmbus_do_probe()

2026-06-01T15:50:50+00:00

commit 491403b9b76cf66abd81301c5901aa4a4549f1e8 upstream. adm1266_probe() calls adm1266_config_gpio() -- which goes on to devm_gpiochip_add_data() and exposes the gpio_chip callbacks to gpiolib -- before pmbus_do_probe() has initialised the per-client PMBus state (notably the pmbus_lock mutex the core hands out via pmbus_get_data()). That ordering is already a latent hazard: any GPIO access that lands between adm1266_config_gpio() and the end of pmbus_do_probe() (for example a sysfs read from a user space agent that opens the gpiochip the instant gpiolib advertises it) races pmbus_do_probe()'s own device accesses with no serialisation. Move adm1266_config_gpio() down past pmbus_do_probe() so the chip isn't reachable from userspace until the PMBus state it depends on is fully initialised. Fixes: d98dfad35c38 ("hwmon: (pmbus/adm1266) Add support for GPIOs") Cc: stable@vger.kernel.org Signed-off-by: Abdurrahman Hussain Reviewed-by: Bartosz Golaszewski Link: https://lore.kernel.org/r/20260518-adm1266-gpio-fixes-v3-4-e425e4f88139@nexthop.ai Signed-off-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman

hwmon: (pmbus/adm1266) don't clobber GPIO bits before PDIO read in get_multiple

2026-06-01T15:50:50+00:00

commit 3327a12aee9e10ffa903e28b8445dfd1af5307c0 upstream. adm1266_gpio_get_multiple() zeroes *bits before the GPIO_STATUS loop and then a second time before the PDIO_STATUS loop: *bits = 0; for_each_set_bit(gpio_nr, mask, ADM1266_GPIO_NR) { ... set_bit(gpio_nr, bits); } ret = i2c_smbus_read_block_data(data->client, ADM1266_PDIO_STATUS, ...); ... *bits = 0; for_each_set_bit_from(gpio_nr, mask, ADM1266_GPIO_NR + ADM1266_PDIO_NR) { ... set_bit(gpio_nr, bits); } The second *bits = 0 throws away every GPIO bit the first loop just populated, so callers asking for any combination of GPIO and PDIO pins always see the GPIO portion of the returned bits as zero. Drop the redundant second assignment so both halves of the result survive. Fixes: d98dfad35c38 ("hwmon: (pmbus/adm1266) Add support for GPIOs") Cc: stable@vger.kernel.org Signed-off-by: Abdurrahman Hussain Reviewed-by: Bartosz Golaszewski Reviewed-by: Linus Walleij Link: https://lore.kernel.org/r/20260518-adm1266-gpio-fixes-v3-2-e425e4f88139@nexthop.ai Signed-off-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman

hwmon: (pmbus/adm1266) cap PDIO scan in get_multiple at ADM1266_PDIO_NR

2026-06-01T15:50:50+00:00

commit d7834d92251baade796812876e95555e2066fa9f upstream. adm1266_gpio_get_multiple() iterates the PDIO portion of the caller-supplied mask using for_each_set_bit_from(gpio_nr, mask, ADM1266_GPIO_NR + ADM1266_PDIO_STATUS) { ... } where ADM1266_PDIO_STATUS is the PMBus command code (0xE9, i.e. 233), not the number of PDIO pins. The intended upper bound is ADM1266_GPIO_NR + ADM1266_PDIO_NR = 25. gpiolib hands in a mask sized for gc.ngpio (= 25 bits on this chip), so the iteration walks find_next_bit() up to 242, reading up to 217 extra bits (a handful of unsigned-long words: four on 64-bit, seven on 32-bit) of whatever lives past the end of the mask in the caller's stack. Any incidental set bit in that range then drives a set_bit(gpio_nr, bits) call that writes past the end of the caller-supplied bits array too -- both out-of-bounds. Substitute ADM1266_PDIO_NR for the constant so the scan stops at the last real PDIO bit. Fixes: d98dfad35c38 ("hwmon: (pmbus/adm1266) Add support for GPIOs") Cc: stable@vger.kernel.org Signed-off-by: Abdurrahman Hussain Reviewed-by: Bartosz Golaszewski Reviewed-by: Linus Walleij Link: https://lore.kernel.org/r/20260518-adm1266-gpio-fixes-v3-1-e425e4f88139@nexthop.ai Signed-off-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman