bus: mhi: host: Drop chan lock before queuing buffers

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: 1d3173a3ba ("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@quicinc.com
[mani: added fixes tag and cc'ed stable]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
This commit is contained in:
Qiang Yu 2023-12-11 14:42:52 +08:00 committed by Manivannan Sadhasivam
parent b89b6a863d
commit 01bd694ac2

View File

@ -644,6 +644,8 @@ static int parse_xfer_event(struct mhi_controller *mhi_cntrl,
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);
@ -669,6 +671,8 @@ static int parse_xfer_event(struct mhi_controller *mhi_cntrl,
kfree(buf_info->cb_buf);
}
}
read_lock_bh(&mhi_chan->lock);
}
break;
} /* CC_EOT */