iio: accel: fxls8962af: Fix use after free in fxls8962af_fifo_flush

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: iio: accel: fxls8962af: Fix use after free in fxls8962af_fifo_flush fxls8962af_fifo_flush() uses indio_dev->active_scan_mask (with iio_for_each_active_channel()) without making sure the indio_dev stays in buffer mode. There is a race if indio_dev exits buffer mode in the middle of the interrupt that flushes the fifo. Fix this by calling synchronize_irq() to ensure that no interrupt is currently running when disabling buffer mode. Unable to handle kernel NULL pointer dereference at virtual address 00000000 when read [...] _find_first_bit_le from fxls8962af_fifo_flush+0x17c/0x290 fxls8962af_fifo_flush from fxls8962af_interrupt+0x80/0x178 fxls8962af_interrupt from irq_thread_fn+0x1c/0x7c irq_thread_fn from irq_thread+0x110/0x1f4 irq_thread from kthread+0xe0/0xfc kthread from ret_from_fork+0x14/0x2c

References

• https://git.kernel.org/stable/c/6ecd61c201b27ad2760b3975437ad2b97d725b98
• https://git.kernel.org/stable/c/dda42f23a8f5439eaac9521ce0531547d880cc54
• https://git.kernel.org/stable/c/bfcda3e1015791b3a63fb4d3aad408da9cf76e8f
• https://git.kernel.org/stable/c/1803d372460aaa9ae0188a30c9421d3f157f2f04
• https://git.kernel.org/stable/c/1fe16dc1a2f5057772e5391ec042ed7442966c9a