patch "bus: mhi: ep: Only send -ENOTCONN status if client driver is" added to char-misc-next

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    bus: mhi: ep: Only send -ENOTCONN status if client driver is

to my char-misc git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-next branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will also be merged in the next major kernel release
during the merge window.

If you have any questions about this process, please let me know.


From e6cebcc27519dcf1652e604c73b9fd4f416987c0 Mon Sep 17 00:00:00 2001
From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Date: Wed, 28 Dec 2022 21:47:01 +0530
Subject: bus: mhi: ep: Only send -ENOTCONN status if client driver is
 available

For the STOP and RESET commands, only send the channel disconnect status
-ENOTCONN if client driver is available. Otherwise, it will result in
null pointer dereference.

Cc: <stable@vger.kernel.org> # 5.19
Fixes: e827569062a8 ("bus: mhi: ep: Add support for processing command rings")
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Link: https://lore.kernel.org/r/20221228161704.255268-4-manivannan.sadhasivam@linaro.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
 drivers/bus/mhi/ep/main.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
index 8b065a3cc848..7d68b00bdbcf 100644
--- a/drivers/bus/mhi/ep/main.c
+++ b/drivers/bus/mhi/ep/main.c
@@ -203,9 +203,11 @@ static int mhi_ep_process_cmd_ring(struct mhi_ep_ring *ring, struct mhi_ring_ele
 		mhi_ep_mmio_disable_chdb(mhi_cntrl, ch_id);
 
 		/* Send channel disconnect status to client drivers */
-		result.transaction_status = -ENOTCONN;
-		result.bytes_xferd = 0;
-		mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
+		if (mhi_chan->xfer_cb) {
+			result.transaction_status = -ENOTCONN;
+			result.bytes_xferd = 0;
+			mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
+		}
 
 		/* Set channel state to STOP */
 		mhi_chan->state = MHI_CH_STATE_STOP;
@@ -235,9 +237,11 @@ static int mhi_ep_process_cmd_ring(struct mhi_ep_ring *ring, struct mhi_ring_ele
 		mhi_ep_ring_reset(mhi_cntrl, ch_ring);
 
 		/* Send channel disconnect status to client driver */
-		result.transaction_status = -ENOTCONN;
-		result.bytes_xferd = 0;
-		mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
+		if (mhi_chan->xfer_cb) {
+			result.transaction_status = -ENOTCONN;
+			result.bytes_xferd = 0;
+			mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
+		}
 
 		/* Set channel state to DISABLED */
 		mhi_chan->state = MHI_CH_STATE_DISABLED;
-- 
2.39.1