From a0fe269293509acdd93b9cfb3f46636f7b91b33a Mon Sep 17 00:00:00 2001 From: Sahaj Chaudhari Date: Sun, 18 Oct 2026 22:20:03 +0530 Subject: [PATCH] gpio: pca953x: Handle direction register read errors in IRQ paths Three IRQ paths ignore the result of reading the direction registers and then use the destination bitmap. pca953x_read_regs() does not populate that bitmap when regmap_bulk_read() fails, leaving the callers to use uninitialized stack data. This can select incorrect GPIOs for direction changes during IRQ bus synchronization, corrupt the saved input state during IRQ setup, or produce incorrect pending interrupt decisions. Check the read result at all three sites. Release irq_lock without changing GPIO directions on failure, leave the IRQ history untouched when pending detection fails, and propagate the error from IRQ setup. The read helper already logs the error. Fixes: 0f25fda840a9 ("gpio: pca953x: Zap ad-hoc reg_direction cache") Cc: stable@vger.kernel.org Signed-off-by: Sahaj Chaudhari Link: https://patch.msgid.link/20261018165003.3372368-1-sahaj123.sc@gmail.com Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpio-pca953x.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c index 869ed4264d48..afec5ec23696 100644 --- a/drivers/gpio/gpio-pca953x.c +++ b/drivers/gpio/gpio-pca953x.c @@ -867,6 +867,7 @@ static void pca953x_irq_bus_sync_unlock(struct irq_data *d) DECLARE_BITMAP(irq_mask, MAX_LINE); DECLARE_BITMAP(reg_direction, MAX_LINE); int level; + int ret; guard(mutex)(&chip->i2c_lock); @@ -885,7 +886,9 @@ static void pca953x_irq_bus_sync_unlock(struct irq_data *d) } /* Switch direction to input if needed */ - pca953x_read_regs(chip, chip->regs->direction, reg_direction); + ret = pca953x_read_regs(chip, chip->regs->direction, reg_direction); + if (ret) + goto out; bitmap_or(irq_mask, chip->irq_trig_fall, chip->irq_trig_raise, gc->ngpio); bitmap_or(irq_mask, irq_mask, chip->irq_trig_level_high, gc->ngpio); @@ -895,6 +898,7 @@ static void pca953x_irq_bus_sync_unlock(struct irq_data *d) for_each_andnot_bit(level, irq_mask, reg_direction, gc->ngpio) pca953x_gpio_direction_input_unlocked(&chip->gpio_chip, level); +out: mutex_unlock(&chip->irq_lock); } @@ -989,7 +993,9 @@ static bool pca953x_irq_pending(struct pca953x_chip *chip, unsigned long *pendin } /* Remove output pins from the equation */ - pca953x_read_regs(chip, chip->regs->direction, reg_direction); + ret = pca953x_read_regs(chip, chip->regs->direction, reg_direction); + if (ret) + return false; bitmap_copy(old_stat, chip->irq_stat, gc->ngpio); @@ -1089,7 +1095,9 @@ static int pca953x_irq_setup(struct pca953x_chip *chip, int irq_base) * interrupt. We have to rely on the previous read for * this purpose. */ - pca953x_read_regs(chip, chip->regs->direction, reg_direction); + ret = pca953x_read_regs(chip, chip->regs->direction, reg_direction); + if (ret) + return ret; bitmap_and(chip->irq_stat, irq_stat, reg_direction, gc->ngpio); mutex_init(&chip->irq_lock);