ata: libata-core: fix NULL pointer deref in ata_host_alloc_pinfo()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: ata: libata-core: fix NULL pointer deref in ata_host_alloc_pinfo() In an unlikely (and probably wrong?) case that the 'ppi' parameter of ata_host_alloc_pinfo() points to an array starting with a NULL pointer, there's going to be a kernel oops as the 'pi' local variable won't get reassigned from the initial value of NULL. Initialize 'pi' instead to '&ata_dummy_port_info' to fix the possible kernel oops for good... Found by Linux Verification Center (linuxtesting.org) with the SVACE static analysis tool.

References

• https://git.kernel.org/stable/c/ca4693e6e06e4fd2b240c0fec47aa2498c94848e
• https://git.kernel.org/stable/c/1ac5efee33f29e704226506d429b84575a5d66f8
• https://git.kernel.org/stable/c/a810bd5af06977a847d1f202b22d7defd5c62497
• https://git.kernel.org/stable/c/253334f84c81bc6a43af489f108c0bddad989eef
• https://git.kernel.org/stable/c/36cd19e7d4e5571d77a2ed20c5b6ef50cf57734a
• https://git.kernel.org/stable/c/ff128fbea720bf763fa345680dda5f050bc24a47
• https://git.kernel.org/stable/c/07cbdb4807d369fbda73062a91b570c4dc5ec429
• https://git.kernel.org/stable/c/bf476fe22aa1851bab4728e0c49025a6a0bea307