CVE-2026-31749comedi: ni_atmio16d: Fix invalid clean-up after failed attach

Official description

In the Linux kernel, the following vulnerability has been resolved: comedi: ni_atmio16d: Fix invalid clean-up after failed attach If the driver's COMEDI "attach" handler function (`atmio16d_attach()`) returns an error, the COMEDI core will call the driver's "detach" handler function (`atmio16d_detach()`) to clean up. This calls `reset_atmio16d()` unconditionally, but depending on where the error occurred in the attach handler, the device may not have been sufficiently initialized to call `reset_atmio16d()`. It uses `dev->iobase` as the I/O port base address and `dev->private` as the pointer to the COMEDI device's private data structure. `dev->iobase` may still be set to its initial value of 0, which would result in undesired writes to low I/O port addresses. `dev->private` may still be `NULL`, which would result in null pointer dereferences. Fix `atmio16d_detach()` by checking that `dev->private` is valid (non-null) before calling `reset_atmio16d()`. This implies that `dev->iobase` was set correctly since that is set up before `dev->private`.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/a01dd339ea6ac58b0967a50085622a6017351140
• https://git.kernel.org/stable/c/933a2d6a95f9bfb203e562c9be1dd990c735535c
• https://git.kernel.org/stable/c/5d8d88c8c0eec230de8f1f60e0920a4337939a88
• https://git.kernel.org/stable/c/f517646e008fe99ca1800601cd011b110f8684ae
• https://git.kernel.org/stable/c/3848ae00b1642e2c98ff8cbfd2d3b38c6f53b5c3
• https://git.kernel.org/stable/c/43c68a2c7cc35b7c2a83c285cb4ad3d472b8caa2
• https://git.kernel.org/stable/c/d07d97ca4f7fac467cdcf4a012690853958b7e89
• https://git.kernel.org/stable/c/101ab946b79ad83b36d5cfd47de587492a80acf0