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 56560AD48 for ; Wed, 4 Jan 2023 16:23:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C9FD3C433D2; Wed, 4 Jan 2023 16:23:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672849383; bh=eTkKD0QLneq/gTEjl7sEcWX6q3OTaP227nVwiEgcnBU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=D4S+n5qZM/EW6B0tlUcznmbf9aDfO9e6iWi+CLoGO7JtiabMX9mLwvFdFd0LCenK+ +Er4zN+0wyYcTbL4yfzGT8KmNSJMEhHHu27NyA9737ipRssiRbsP1C0HiNtTGngPjs WNH1iFFz5srJnNZYSRQxVdSE56l2Di5bNIaQYq4o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Qiang Yu , Manivannan Sadhasivam , Manivannan Sadhasivam Subject: [PATCH 6.0 112/177] bus: mhi: host: Fix race between channel preparation and M0 event Date: Wed, 4 Jan 2023 17:06:43 +0100 Message-Id: <20230104160511.037198241@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230104160507.635888536@linuxfoundation.org> References: <20230104160507.635888536@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Qiang Yu commit 869a99907faea6d1835b0bd0d0422ae3519c6ea9 upstream. There is a race condition where mhi_prepare_channel() updates the read and write pointers as the base address and in parallel, if an M0 transition occurs, the tasklet goes ahead and rings doorbells for all channels with a delta in TRE rings assuming they are already enabled. This causes a null pointer access. Fix it by adding a channel enabled check before ringing channel doorbells. Cc: stable@vger.kernel.org # 5.19 Fixes: a6e2e3522f29 "bus: mhi: core: Add support for PM state transitions" Signed-off-by: Qiang Yu Reviewed-by: Manivannan Sadhasivam Link: https://lore.kernel.org/r/1665889532-13634-1-git-send-email-quic_qianyu@quicinc.com [mani: CCed stable list] Signed-off-by: Manivannan Sadhasivam Signed-off-by: Greg Kroah-Hartman --- drivers/bus/mhi/host/pm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c index 4a42186ff111..083459028a4b 100644 --- a/drivers/bus/mhi/host/pm.c +++ b/drivers/bus/mhi/host/pm.c @@ -301,7 +301,8 @@ int mhi_pm_m0_transition(struct mhi_controller *mhi_cntrl) read_lock_irq(&mhi_chan->lock); /* Only ring DB if ring is not empty */ - if (tre_ring->base && tre_ring->wp != tre_ring->rp) + if (tre_ring->base && tre_ring->wp != tre_ring->rp && + mhi_chan->ch_state == MHI_CH_STATE_ENABLED) mhi_ring_chan_db(mhi_cntrl, mhi_chan); read_unlock_irq(&mhi_chan->lock); } -- 2.39.0