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There are rare cases where an rpcrdma_req can be re-used (via rpcrdma_buffer_put) while the RPC reply handler is still running. This is due to a signal firing at just the wrong instant. Since commit9d6b040978("xprtrdma: Place registered MWs on a per-req list"), rpcrdma_mws are self-contained; ie., they fully describe an MR and scatterlist, and no part of that information is stored in struct rpcrdma_req. As part of closing the above race window, pass only the req's list of registered MRs to ro_unmap_sync, rather than the rpcrdma_req itself. Some extra transport header sanity checking is removed. Since the client depends on its own recollection of what memory had been registered, there doesn't seem to be a way to abuse this change. And, the check was not terribly effective. If the client had sent Read chunks, the "list_empty" test is negative in both of the removed cases, which are actually looking for Write or Reply chunks. BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=305 Fixes:68791649a7('xprtrdma: Invalidate in the RPC reply ... ') Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.