From: Qiang Yu Date: Mon, 11 Dec 2023 06:42:52 +0000 (+0800) Subject: bus: mhi: host: Drop chan lock before queuing buffers X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=01bd694ac2f682fb8017e16148b928482bc8fa4b;p=linux.git 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: # 5.7 Fixes: 1d3173a3bae7 ("bus: mhi: core: Add support for processing events from client device") Signed-off-by: Qiang Yu Reviewed-by: Jeffrey Hugo Tested-by: Jeffrey Hugo Reviewed-by: Manivannan Sadhasivam 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 --- diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c index ad7807e4b523b..abb561db9ae1d 100644 --- a/drivers/bus/mhi/host/main.c +++ b/drivers/bus/mhi/host/main.c @@ -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 */