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[199.106.103.254]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-742a970b7bcsm10081510b3a.52.2025.05.21.09.39.55 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 21 May 2025 09:39:55 -0700 (PDT) Message-ID: Date: Wed, 21 May 2025 10:39:54 -0600 Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] bus: mhi: host: Detect events pointing to unexpected TREs To: Youssef Samir , manivannan.sadhasivam@linaro.org, quic_carlv@quicinc.com, quic_thanson@quicinc.com Cc: mhi@lists.linux.dev, linux-arm-msm@vger.kernel.org References: <20250521163110.571893-1-quic_yabdulra@quicinc.com> Content-Language: en-US From: Jeff Hugo In-Reply-To: <20250521163110.571893-1-quic_yabdulra@quicinc.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNTIxMDE2NCBTYWx0ZWRfX0Puss/KiqV50 nGl04q/Le1FdPIW0LdHCbOggNYhj9D+RLhhUk9N3nCTe7Btk+zT5c5esCDare7y7xgt+CsYae4m 8CQU+YmrAVjLSceTOJQtFitMc81+j7sexbVR1Dsx/7k0NmCVS8KbA1qHF6GRM/1UnF6SGhh66b3 4OQn/xqCfobPU8Gbpj3ufFQWnj1Tf9KbJsNC/Z6vH1pRDZe9vCNgXVHI+7ijD1cyad/lREB2h9r 2qII2J40fT+57t4KG9sR/tJoQtF0vmQ8dx1s/WhuOdRoHX8iLe8IQWzBXLVNxtzc7LeeaFkjDa3 iR4OqEHbJFXQb50o/9RrKw8cY5YxvmcOo/sC0x5bqVh7oDWC+tbE+5L9YNdDw5Pk4ZBjO6/owOZ B0a2KnBBHY3JTfk0FmxFl0bRSJ4CrV3n8V91H1IfGOCApHNokRWQHXpTylLTGI4jFKrKFW8n X-Authority-Analysis: v=2.4 cv=RIuzH5i+ c=1 sm=1 tr=0 ts=682e01dd cx=c_pps a=mDZGXZTwRPZaeRUbqKGCBw==:117 a=JYp8KDb2vCoCEuGobkYCKw==:17 a=IkcTkHD0fZMA:10 a=dt9VzEwgFbYA:10 a=COk6AnOGAAAA:8 a=EUspDBNiAAAA:8 a=MlxiPQrgYWHJ-qK4OrsA:9 a=QEXdDO2ut3YA:10 a=zc0IvFSfCIW2DFIPzwfm:22 a=TjNXssC_j7lpFel5tvFf:22 X-Proofpoint-ORIG-GUID: rg1-yA10D6O0DbdPKo_W5RvsIjW240bn X-Proofpoint-GUID: rg1-yA10D6O0DbdPKo_W5RvsIjW240bn X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.0.736,FMLib:17.12.80.40 definitions=2025-05-21_05,2025-05-20_03,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 phishscore=0 suspectscore=0 malwarescore=0 bulkscore=0 mlxlogscore=999 spamscore=0 lowpriorityscore=0 mlxscore=0 priorityscore=1501 adultscore=0 impostorscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2505160000 definitions=main-2505210164 On 5/21/2025 10:31 AM, Youssef Samir wrote: > When a remote device sends a completion event to the host, it contains a > pointer to the consumed TRE. The host uses this pointer to process all of > the TREs between it and the host's local copy of the ring's read pointer. > This works when processing completion for chained transactions, but can > lead to nasty results if the device sends an event for a single-element > transaction with a read pointer that is multiple elements ahead of the > host's read pointer. > > For instance, if the host accesses an event ring while the device is > updating it, the pointer inside of the event might still point to an old > TRE. If the host uses the channel's xfer_cb() to directly free the buffer > pointed to by the TRE, the buffer will be double-freed. > > Validate the pointer inside an event before processing it. > > Fixes: 1d3173a3bae7 ("bus: mhi: core: Add support for processing events from client device") > Signed-off-by: Youssef Samir Reviewed-by: Jeff Hugo