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| author | Ian Ray <ian.ray@gehealthcare.com> | 2024-06-20 07:29:15 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-07-25 09:50:50 +0200 |
| commit | e2ecdddca80dd845df42376e4b0197fe97018ba2 (patch) | |
| tree | b37d2241cfd03dea5171885ef6722e2f0d47dab7 /drivers/gpio | |
| parent | e4fca9acc7c53689e0e490845dcef35ec2dcdd0f (diff) | |
| download | linux-e2ecdddca80dd845df42376e4b0197fe97018ba2.tar.gz linux-e2ecdddca80dd845df42376e4b0197fe97018ba2.tar.bz2 linux-e2ecdddca80dd845df42376e4b0197fe97018ba2.zip | |
gpio: pca953x: fix pca953x_irq_bus_sync_unlock race
[ Upstream commit bfc6444b57dc7186b6acc964705d7516cbaf3904 ]
Ensure that `i2c_lock' is held when setting interrupt latch and mask in
pca953x_irq_bus_sync_unlock() in order to avoid races.
The other (non-probe) call site pca953x_gpio_set_multiple() ensures the
lock is held before calling pca953x_write_regs().
The problem occurred when a request raced against irq_bus_sync_unlock()
approximately once per thousand reboots on an i.MX8MP based system.
* Normal case
0-0022: write register AI|3a {03,02,00,00,01} Input latch P0
0-0022: write register AI|49 {fc,fd,ff,ff,fe} Interrupt mask P0
0-0022: write register AI|08 {ff,00,00,00,00} Output P3
0-0022: write register AI|12 {fc,00,00,00,00} Config P3
* Race case
0-0022: write register AI|08 {ff,00,00,00,00} Output P3
0-0022: write register AI|08 {03,02,00,00,01} *** Wrong register ***
0-0022: write register AI|12 {fc,00,00,00,00} Config P3
0-0022: write register AI|49 {fc,fd,ff,ff,fe} Interrupt mask P0
Signed-off-by: Ian Ray <ian.ray@gehealthcare.com>
Link: https://lore.kernel.org/r/20240620042915.2173-1-ian.ray@gehealthcare.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/gpio')
| -rw-r--r-- | drivers/gpio/gpio-pca953x.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c index bdd50a78e414..ce9a94e33280 100644 --- a/drivers/gpio/gpio-pca953x.c +++ b/drivers/gpio/gpio-pca953x.c @@ -766,6 +766,8 @@ static void pca953x_irq_bus_sync_unlock(struct irq_data *d) int level; if (chip->driver_data & PCA_PCAL) { + guard(mutex)(&chip->i2c_lock); + /* Enable latch on interrupt-enabled inputs */ pca953x_write_regs(chip, PCAL953X_IN_LATCH, chip->irq_mask); |