In the Linux kernel, the following vulnerability has been resolved:
wan: wanxl: Only reset hardware after BAR mapping
wanxl_pci_init_one() stores the freshly allocated card in driver data before the PLX BAR is mapped. Several early probe failures then unwind through wanxl_pci_remove_one(), including failure to allocate the coherent status area or to restore the DMA mask.
wanxl_pci_remove_one() unconditionally calls wanxl_reset(), and wanxl_reset() dereferences card->plx. On those early failures card->plx is still NULL, so the error path can dereference a NULL MMIO pointer.
Only issue the hardware reset once the BAR mapping exists. The remaining cleanup in wanxl_pci_remove_one() already checks whether later resources were allocated.
This issue was found by a static analysis checker and confirmed by manual source review.
References
- https://git.kernel.org/stable/c/2fe22d58b3797d741570f9873b26653fd511576c
- https://git.kernel.org/stable/c/59cbe6cfa0fa23c192351cc284e30707309f6741
- https://git.kernel.org/stable/c/91957b89da995607cb654b1f9a3c126ddbaee10f
- https://git.kernel.org/stable/c/b9e2ff70e96acf83693b27987e0390bad9f83efa
- https://git.kernel.org/stable/c/f4834132773f15ffb255127499c8443947fa7d0f