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bus: mhi: host: Fix race between unprepare and queue_buf

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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>
This commit is contained in:
Jeffrey Hugo 2025-03-06 10:29:13 -07:00 committed by Manivannan Sadhasivam
parent cba6bdfd79
commit 0686a818d7
1 changed files with 10 additions and 6 deletions

16
drivers/bus/mhi/host/main.c

@ -1188,11 +1188,16 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
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;
@ -1210,10 +1215,8 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
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);
@ -1231,9 +1234,10 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
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,