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authorNeilBrown <neilb@suse.de>2023-05-09 01:42:47 +0200
committerChuck Lever <chuck.lever@oracle.com>2023-05-14 21:55:02 +0200
commit948f072ada23e0a504c5e4d7d71d4c83bd0785ec (patch)
tree35e02b9a854af2107953dc9e7150bc98be37e453 /net/sunrpc/xprtrdma
parentSUNRPC: double free xprt_ctxt while still in use (diff)
downloadlinux-948f072ada23e0a504c5e4d7d71d4c83bd0785ec.tar.xz
linux-948f072ada23e0a504c5e4d7d71d4c83bd0785ec.zip
SUNRPC: always free ctxt when freeing deferred request
Since the ->xprt_ctxt pointer was added to svc_deferred_req, it has not been sufficient to use kfree() to free a deferred request. We may need to free the ctxt as well. As freeing the ctxt is all that ->xpo_release_rqst() does, we repurpose it to explicit do that even when the ctxt is not stored in an rqst. So we now have ->xpo_release_ctxt() which is given an xprt and a ctxt, which may have been taken either from an rqst or from a dreq. The caller is now responsible for clearing that pointer after the call to ->xpo_release_ctxt. We also clear dr->xprt_ctxt when the ctxt is moved into a new rqst when revisiting a deferred request. This ensures there is only one pointer to the ctxt, so the risk of double freeing in future is reduced. The new code in svc_xprt_release which releases both the ctxt and any rq_deferred depends on this. Fixes: 773f91b2cf3f ("SUNRPC: Fix NFSD's request deferral on RDMA transports") Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'net/sunrpc/xprtrdma')
-rw-r--r--net/sunrpc/xprtrdma/svc_rdma_recvfrom.c11
-rw-r--r--net/sunrpc/xprtrdma/svc_rdma_transport.c2
2 files changed, 6 insertions, 7 deletions
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index 1c658fa43063..a22fe7587fa6 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -239,21 +239,20 @@ void svc_rdma_recv_ctxt_put(struct svcxprt_rdma *rdma,
}
/**
- * svc_rdma_release_rqst - Release transport-specific per-rqst resources
- * @rqstp: svc_rqst being released
+ * svc_rdma_release_ctxt - Release transport-specific per-rqst resources
+ * @xprt: the transport which owned the context
+ * @vctxt: the context from rqstp->rq_xprt_ctxt or dr->xprt_ctxt
*
* Ensure that the recv_ctxt is released whether or not a Reply
* was sent. For example, the client could close the connection,
* or svc_process could drop an RPC, before the Reply is sent.
*/
-void svc_rdma_release_rqst(struct svc_rqst *rqstp)
+void svc_rdma_release_ctxt(struct svc_xprt *xprt, void *vctxt)
{
- struct svc_rdma_recv_ctxt *ctxt = rqstp->rq_xprt_ctxt;
- struct svc_xprt *xprt = rqstp->rq_xprt;
+ struct svc_rdma_recv_ctxt *ctxt = vctxt;
struct svcxprt_rdma *rdma =
container_of(xprt, struct svcxprt_rdma, sc_xprt);
- rqstp->rq_xprt_ctxt = NULL;
if (ctxt)
svc_rdma_recv_ctxt_put(rdma, ctxt);
}
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 416b298f74dd..ca04f7a6a085 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -80,7 +80,7 @@ static const struct svc_xprt_ops svc_rdma_ops = {
.xpo_recvfrom = svc_rdma_recvfrom,
.xpo_sendto = svc_rdma_sendto,
.xpo_result_payload = svc_rdma_result_payload,
- .xpo_release_rqst = svc_rdma_release_rqst,
+ .xpo_release_ctxt = svc_rdma_release_ctxt,
.xpo_detach = svc_rdma_detach,
.xpo_free = svc_rdma_free,
.xpo_has_wspace = svc_rdma_has_wspace,