CVE-2022-48994

In the Linux kernel, the following vulnerability has been resolved:

ALSA: seq: Fix function prototype mismatch in sndseqexpandvarevent

With clang's kernel control flow integrity (kCFI, CONFIGCFICLANG), indirect call targets are validated against the expected function pointer prototype to make sure the call target is valid to help mitigate ROP attacks. If they are not identical, there is a failure at run time, which manifests as either a kernel panic or thread getting killed.

seqcopyinuser() and seqcopyinkernel() did not have prototypes matching sndseqdumpfunct. Adjust this and remove the casts. There are not resulting binary output differences.

This was found as a result of Clang's new -Wcast-function-type-strict flag, which is more sensitive than the simpler -Wcast-function-type, which only checks for type width mismatches.