CVE-2026-80678i2c: imx: Fix slave registration race and error handling

Official description

In the Linux kernel, the following vulnerability has been resolved: i2c: imx: Fix slave registration race and error handling In i2c_imx_reg_slave(), the slave pointer was assigned before pm_runtime_resume_and_get(). If pm_runtime_resume_and_get() failed, the error path returned without clearing i2c_imx->slave, leaving it non-NULL and causing all subsequent registration attempts to fail with -EBUSY. Additionally, because this driver uses a shared IRQ, the interrupt handler i2c_imx_isr() can execute concurrently and, after acquiring slave_lock, dereference i2c_imx->slave. The previous fix attempt added a lockless i2c_imx->slave = NULL on the error path, but that could race with the ISR under the lock and still cause a NULL pointer dereference. Fix both issues by deferring the assignment of i2c_imx->slave and i2c_imx->last_slave_event to after a successful resume, and by performing the assignment inside the slave_lock critical section. This guarantees that the slave pointer is never left stale on the error path and is always valid when observed by the interrupt handler.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/754bc62f72fd64b202462367134ac8ce95b005de
• https://git.kernel.org/stable/c/cfdf6e13518589f911b7eace6ccb788e4ed87397
• https://git.kernel.org/stable/c/b9f6f4883b9ac86654e75899d0dbf8a7a96ad5d8
• https://git.kernel.org/stable/c/d6748f6802f3eebafaa16a5e5dcfbfb9b3bc173f
• https://git.kernel.org/stable/c/12a4f0950a158d98552cbaeacc35edccd8d975fa
• https://git.kernel.org/stable/c/614ca6594e301ff682999797c2216e9685558a2b
• https://git.kernel.org/stable/c/d64ec362c369bbc33833f7936d5f3a706b0d5c45