6.1-stable review patch. If anyone has any objections, please let me know.
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From: Qiang Yu quic_qianyu@quicinc.com
commit 01bd694ac2f682fb8017e16148b928482bc8fa4b upstream.
Ensure read and write locks for the channel are not taken in succession by dropping the read lock from parse_xfer_event() such that a callback given to client can potentially queue buffers and acquire the write lock in that process. Any queueing of buffers should be done without channel read lock acquired as it can result in multiple locks and a soft lockup.
Cc: stable@vger.kernel.org # 5.7 Fixes: 1d3173a3bae7 ("bus: mhi: core: Add support for processing events from client device") Signed-off-by: Qiang Yu quic_qianyu@quicinc.com Reviewed-by: Jeffrey Hugo quic_jhugo@quicinc.com Tested-by: Jeffrey Hugo quic_jhugo@quicinc.com Reviewed-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Link: https://lore.kernel.org/r/1702276972-41296-3-git-send-email-quic_qianyu@quic... [mani: added fixes tag and cc'ed stable] Signed-off-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/bus/mhi/host/main.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/drivers/bus/mhi/host/main.c +++ b/drivers/bus/mhi/host/main.c @@ -643,6 +643,8 @@ static int parse_xfer_event(struct mhi_c mhi_del_ring_element(mhi_cntrl, tre_ring); local_rp = tre_ring->rp;
+ read_unlock_bh(&mhi_chan->lock); + /* notify client */ mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
@@ -668,6 +670,8 @@ static int parse_xfer_event(struct mhi_c kfree(buf_info->cb_buf); } } + + read_lock_bh(&mhi_chan->lock); } break; } /* CC_EOT */