The patch below does not apply to the 4.16-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From c5157b76869ba98c3a99a1982396437464e131a6 Mon Sep 17 00:00:00 2001
From: Ioan Nicu ioan.nicu.ext@nokia.com Date: Fri, 20 Apr 2018 14:55:49 -0700 Subject: [PATCH] rapidio: fix rio_dma_transfer error handling
Some of the mport_dma_req structure members were initialized late inside the do_dma_request() function, just before submitting the request to the dma engine. But we have some error branches before that. In case of such an error, the code would return on the error path and trigger the calling of dma_req_free() with a req structure which is not completely initialized. This causes a NULL pointer dereference in dma_req_free().
This patch fixes these error branches by making sure that all necessary mport_dma_req structure members are initialized in rio_dma_transfer() immediately after the request structure gets allocated.
Link: http://lkml.kernel.org/r/20180412150605.GA31409@nokia.com Fixes: bbd876adb8c72 ("rapidio: use a reference count for struct mport_dma_req") Signed-off-by: Ioan Nicu ioan.nicu.ext@nokia.com Tested-by: Alexander Sverdlin alexander.sverdlin@nokia.com Acked-by: Alexandre Bounine alex.bou9@gmail.com Cc: Barry Wood barry.wood@idt.com Cc: Matt Porter mporter@kernel.crashing.org Cc: Christophe JAILLET christophe.jaillet@wanadoo.fr Cc: Logan Gunthorpe logang@deltatee.com Cc: Chris Wilson chris@chris-wilson.co.uk Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com Cc: Frank Kunz frank.kunz@nokia.com Cc: stable@vger.kernel.org [4.6+] Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org
diff --git a/drivers/rapidio/devices/rio_mport_cdev.c b/drivers/rapidio/devices/rio_mport_cdev.c index 9d27016c899e..0434ab7b6497 100644 --- a/drivers/rapidio/devices/rio_mport_cdev.c +++ b/drivers/rapidio/devices/rio_mport_cdev.c @@ -740,10 +740,7 @@ static int do_dma_request(struct mport_dma_req *req, tx->callback = dma_xfer_callback; tx->callback_param = req;
- req->dmach = chan; - req->sync = sync; req->status = DMA_IN_PROGRESS; - init_completion(&req->req_comp); kref_get(&req->refcount);
cookie = dmaengine_submit(tx); @@ -831,13 +828,20 @@ rio_dma_transfer(struct file *filp, u32 transfer_mode, if (!req) return -ENOMEM;
- kref_init(&req->refcount); - ret = get_dma_channel(priv); if (ret) { kfree(req); return ret; } + chan = priv->dmach; + + kref_init(&req->refcount); + init_completion(&req->req_comp); + req->dir = dir; + req->filp = filp; + req->priv = priv; + req->dmach = chan; + req->sync = sync;
/* * If parameter loc_addr != NULL, we are transferring data from/to @@ -925,11 +929,6 @@ rio_dma_transfer(struct file *filp, u32 transfer_mode, xfer->offset, xfer->length); }
- req->dir = dir; - req->filp = filp; - req->priv = priv; - chan = priv->dmach; - nents = dma_map_sg(chan->device->dev, req->sgt.sgl, req->sgt.nents, dir); if (nents == 0) {