From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5FAD01429E for ; Tue, 19 Dec 2023 07:59:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="K90K5608" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8EC36C433C8; Tue, 19 Dec 2023 07:59:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1702972789; bh=Y/FoWFLrq64u10X7jS4s/VBYNWNFIuCrD3nZOM1Tufw=; h=Subject:To:From:Date:From; b=K90K5608R5mopiaXryvn4dxhLR+DEkYG1U+Njc4cYW0aVSdvCtrHHpE6+EipNRm7v RKRfzPiYGzC95Gr3T/YE/9NUrlpBu01zFGSDYgek0uH0S0ZpGRoowOSsHGg6ZqJ/Xr DiyEzj5PjyWtmju/6opopiR6Xtjd2RtBPALaDSdY= Subject: patch "bus: mhi: host: Drop chan lock before queuing buffers" added to char-misc-next To: quic_qianyu@quicinc.com,manivannan.sadhasivam@linaro.org,quic_jhugo@quicinc.com,stable@vger.kernel.org From: Date: Tue, 19 Dec 2023 08:59:06 +0100 Message-ID: <2023121906-usable-pardon-5ca6@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit This is a note to let you know that I've just added the patch titled bus: mhi: host: Drop chan lock before queuing buffers to my char-misc git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git in the char-misc-next branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will also be merged in the next major kernel release during the merge window. If you have any questions about this process, please let me know. >From 01bd694ac2f682fb8017e16148b928482bc8fa4b Mon Sep 17 00:00:00 2001 From: Qiang Yu Date: Mon, 11 Dec 2023 14:42:52 +0800 Subject: 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 --- 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 ad7807e4b523..abb561db9ae1 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 */ -- 2.43.0