misc: fastrpc: Don't reference rpmsg_device after remove

As fastrpc_rpmsg_remove() returns the rpdev of the channel context is no
longer a valid object, so ensure to update the channel context to no
longer reference the old object and guard in the invoke code path
against dereferencing it.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Mayank Chopra <mak.chopra@codeaurora.org>
Signed-off-by: Abhinav Asati <asatiabhi@codeaurora.org>
Signed-off-by: Vamsi Singamsetty <vamssi@codeaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20190829092926.12037-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index c019e86..59ee6de 100644 (file)
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -913,6 +913,9 @@ static int fastrpc_internal_invoke(struct fastrpc_user *fl,  u32 kernel,
        if (!fl->sctx)
                return -EINVAL;
 
+       if (!fl->cctx->rpdev)
+               return -EPIPE;
+
        ctx = fastrpc_context_alloc(fl, kernel, sc, args);
        if (IS_ERR(ctx))
                return PTR_ERR(ctx);
@@ -1495,6 +1498,7 @@ static void fastrpc_rpmsg_remove(struct rpmsg_device *rpdev)
        misc_deregister(&cctx->miscdev);
        of_platform_depopulate(&rpdev->dev);
 
+       cctx->rpdev = NULL;
        fastrpc_channel_ctx_put(cctx);
 }