gpio: pca953x: fix pca953x_irq_bus_sync_unlock race

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: gpio: pca953x: fix pca953x_irq_bus_sync_unlock race 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

References

• https://git.kernel.org/stable/c/58a5c93bd1a6e949267400080f07e57ffe05ec34
• https://git.kernel.org/stable/c/e2ecdddca80dd845df42376e4b0197fe97018ba2
• https://git.kernel.org/stable/c/de7cffa53149c7b48bd1bb29b02390c9f05b7f41
• https://git.kernel.org/stable/c/bfc6444b57dc7186b6acc964705d7516cbaf3904