This is a note to let you know that I've just added the patch titled
bus: mhi: ep: Move chan->lock to the start of processing queued ch ring
to the 6.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bus-mhi-ep-move-chan-lock-to-the-start-of-processing-queued-ch-ring.patch
and it can be found in the queue-6.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 8d6a1fea53864cd9545741f48f4ae4df804db557 Mon Sep 17 00:00:00 2001
From: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Date: Wed, 28 Dec 2022 21:47:03 +0530
Subject: bus: mhi: ep: Move chan->lock to the start of processing queued ch ring
From: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
commit 8d6a1fea53864cd9545741f48f4ae4df804db557 upstream.
There is a good chance that while the channel ring gets processed, the STOP
or RESET command for the channel might be received from the MHI host. In
those cases, the entire channel ring processing needs to be protected by
chan->lock to prevent the race where the corresponding channel ring might
be reset.
While at it, let's also add a sanity check to make sure that the ring is
started before processing it. Because, if the STOP/RESET command gets
processed while mhi_ep_ch_ring_worker() waited for chan->lock, the ring
would've been reset.
Cc: <stable@xxxxxxxxxxxxxxx> # 5.19
Fixes: 03c0bb8ec983 ("bus: mhi: ep: Add support for processing channel rings")
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Reviewed-by: Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20221228161704.255268-6-manivannan.sadhasivam@xxxxxxxxxx
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/bus/mhi/ep/main.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
--- a/drivers/bus/mhi/ep/main.c
+++ b/drivers/bus/mhi/ep/main.c
@@ -723,24 +723,37 @@ static void mhi_ep_ch_ring_worker(struct
list_del(&itr->node);
ring = itr->ring;
+ chan = &mhi_cntrl->mhi_chan[ring->ch_id];
+ mutex_lock(&chan->lock);
+
+ /*
+ * The ring could've stopped while we waited to grab the (chan->lock), so do
+ * a sanity check before going further.
+ */
+ if (!ring->started) {
+ mutex_unlock(&chan->lock);
+ kfree(itr);
+ continue;
+ }
+
/* Update the write offset for the ring */
ret = mhi_ep_update_wr_offset(ring);
if (ret) {
dev_err(dev, "Error updating write offset for ring\n");
+ mutex_unlock(&chan->lock);
kfree(itr);
continue;
}
/* Sanity check to make sure there are elements in the ring */
if (ring->rd_offset == ring->wr_offset) {
+ mutex_unlock(&chan->lock);
kfree(itr);
continue;
}
el = &ring->ring_cache[ring->rd_offset];
- chan = &mhi_cntrl->mhi_chan[ring->ch_id];
- mutex_lock(&chan->lock);
dev_dbg(dev, "Processing the ring for channel (%u)\n", ring->ch_id);
ret = mhi_ep_process_ch_ring(ring, el);
if (ret) {
Patches currently in stable-queue which might be from manivannan.sadhasivam@xxxxxxxxxx are
queue-6.2/bus-mhi-ep-save-channel-state-locally-during-suspend-and-resume.patch
queue-6.2/remoteproc-qcom_q6v5_mss-use-a-carveout-to-authentic.patch
queue-6.2/arm-dts-qcom-sdx55-add-qcom-smmu-500-as-the-fallback-for-iommu-node.patch
queue-6.2/bus-mhi-ep-move-chan-lock-to-the-start-of-processing-queued-ch-ring.patch
queue-6.2/bus-mhi-ep-only-send-enotconn-status-if-client-driver-is-available.patch
queue-6.2/revert-remoteproc-qcom_q6v5_mss-map-unmap-metadata-r.patch
queue-6.2/dmaengine-dw-edma-fix-missing-src-dst-address-of-int.patch
queue-6.2/arm-dts-qcom-sdx65-add-qcom-smmu-500-as-the-fallback-for-iommu-node.patch
