From: Qiang Yu quic_qianyu@quicinc.com

stable inclusion from stable-v5.10.209 commit 20a6dea2d1c68d4e03c6bb50bc12e72e226b5c0e category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I97NHA CVE: CVE-2023-52493

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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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 Signed-off-by: Guan Jing guanjing6@huawei.com --- drivers/bus/mhi/host/main.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c index 82d6e9e8bddf..b0a83a725069 100644 --- a/drivers/bus/mhi/host/main.c +++ b/drivers/bus/mhi/host/main.c @@ -570,6 +570,8 @@ 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);

@@ -592,6 +594,8 @@ static int parse_xfer_event(struct mhi_controller *mhi_cntrl, kfree(buf_info->cb_buf); } } + + read_lock_bh(&mhi_chan->lock); } break; } /* CC_EOT */