6.6-stable review patch. If anyone has any objections, please let me know.
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From: Jeff Hugo quic_jhugo@quicinc.com
commit 0686a818d77a431fc3ba2fab4b46bbb04e8c9380 upstream.
A client driver may use mhi_unprepare_from_transfer() to quiesce incoming data during the client driver's tear down. The client driver might also be processing data at the same time, resulting in a call to mhi_queue_buf() which will invoke mhi_gen_tre(). If mhi_gen_tre() runs after mhi_unprepare_from_transfer() has torn down the channel, a panic will occur due to an invalid dereference leading to a page fault.
This occurs because mhi_gen_tre() does not verify the channel state after locking it. Fix this by having mhi_gen_tre() confirm the channel state is valid, or return error to avoid accessing deinitialized data.
Cc: stable@vger.kernel.org # 6.8 Fixes: b89b6a863dd5 ("bus: mhi: host: Add spinlock to protect WP access when queueing TREs") Signed-off-by: Jeffrey Hugo quic_jhugo@quicinc.com Signed-off-by: Jeff Hugo jeff.hugo@oss.qualcomm.com Reviewed-by: Krishna Chaitanya Chundru krishna.chundru@oss.qualcomm.com Reviewed-by: Youssef Samir quic_yabdulra@quicinc.com Reviewed-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Reviewed-by: Troy Hanson quic_thanson@quicinc.com Link: https://lore.kernel.org/r/20250306172913.856982-1-jeff.hugo@oss.qualcomm.com [mani: added stable tag] Signed-off-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/bus/mhi/host/main.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-)
--- a/drivers/bus/mhi/host/main.c +++ b/drivers/bus/mhi/host/main.c @@ -1204,11 +1204,16 @@ int mhi_gen_tre(struct mhi_controller *m struct mhi_ring_element *mhi_tre; struct mhi_buf_info *buf_info; int eot, eob, chain, bei; - int ret; + int ret = 0;
/* Protect accesses for reading and incrementing WP */ write_lock_bh(&mhi_chan->lock);
+ if (mhi_chan->ch_state != MHI_CH_STATE_ENABLED) { + ret = -ENODEV; + goto out; + } + buf_ring = &mhi_chan->buf_ring; tre_ring = &mhi_chan->tre_ring;
@@ -1226,10 +1231,8 @@ int mhi_gen_tre(struct mhi_controller *m
if (!info->pre_mapped) { ret = mhi_cntrl->map_single(mhi_cntrl, buf_info); - if (ret) { - write_unlock_bh(&mhi_chan->lock); - return ret; - } + if (ret) + goto out; }
eob = !!(flags & MHI_EOB); @@ -1246,9 +1249,10 @@ int mhi_gen_tre(struct mhi_controller *m mhi_add_ring_element(mhi_cntrl, tre_ring); mhi_add_ring_element(mhi_cntrl, buf_ring);
+out: write_unlock_bh(&mhi_chan->lock);
- return 0; + return ret; }
int mhi_queue_buf(struct mhi_device *mhi_dev, enum dma_data_direction dir,