In the Linux kernel, the following vulnerability has been resolved: NFSv4.2: Rework scratch handling for READPLUS (again) I found that the read code might send multiple requests using the same nfspgioheader, but nfs4procreadsetup() is only called once. This is how we ended up occasionally double-freeing the scratch buffer, but also means we set a NULL pointer but non-zero length to the xdr scratch buffer. This results in an oops the first time decoding needs to copy something to scratch, which frequently happens when decoding READPLUS hole segments. I fix this by moving scratch handling into the pageio read code. I provide a function to allocate scratch space for decoding read replies, and free the scratch buffer when the nfspgio_header is freed.