xprtrdma: Fix XDRBUF_SPARSE_PAGES support

Olga K. observed that rpcrdma_marsh_req() allocates sparse pages
only when it has determined that a Reply chunk is necessary. There
are plenty of cases where no Reply chunk is needed, but the
XDRBUF_SPARSE_PAGES flag is set. The result would be a crash in
rpcrdma_inline_fixup() when it tries to copy parts of the received
Reply into a missing page.

To avoid crashing, handle sparse page allocation up front.

Until XATTR support was added, this issue did not appear often
because the only SPARSE_PAGES consumer always expected a reply large
enough to always require a Reply chunk.

Reported-by: Olga Kornievskaia <[email protected]>
Signed-off-by: Chuck Lever <[email protected]>
Cc: <[email protected]>
Signed-off-by: Trond Myklebust <[email protected]>

0 files changed, 0 insertions, 0 deletions