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Mon, 20 Jul 2026 21:48:24 +0000 (GMT) Received: from [9.61.255.134] (unknown [9.61.255.134]) by smtpav01.wdc07v.mail.ibm.com (Postfix) with ESMTP; Mon, 20 Jul 2026 21:48:24 +0000 (GMT) Message-ID: <74b5de0b-b52f-40a8-8fca-9876bb12ac48@linux.ibm.com> Date: Mon, 20 Jul 2026 14:48:24 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/7] s390/vfio_ccw: free all memory if cp_init() fails To: Eric Farman , linux-s390@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Matthew Rosato , Halil Pasic , Christian Borntraeger , stable@vger.kernel.org References: <20260720201931.976660-1-farman@linux.ibm.com> <20260720201931.976660-2-farman@linux.ibm.com> Content-Language: en-US From: Farhan Ali In-Reply-To: <20260720201931.976660-2-farman@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: xj5j8ABTRqGKgo5hDMGmx-NQytJnYyY8 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzIwMDIzNSBTYWx0ZWRfXyh1cARZe9Rte Bbc791uQ1ynOHkpsXFb0+CKeZEXQ1CKS0cUbiHT5/0SPEueYy0xTrdULQxGC0Noo+0flbzdRcpL 92oKTV3KKjUES3Fu8KR5mXHNrLyJwlTHGIwNQ+ks0j79sBLOLY8yW0OrZVwwFkBORnQ5m8lDVyp neC7RyWpJunYrodAHac9ppkkjzEkqRiX+JFH9095IAoCTmSCtxUp7PMKKpnVGvCRRtU3v+OckIv F4mhVb666rafReCFcGGpzOl25/+9X5FPHXF5/0w+f9vYrH2M4Dx4/V4d+wGAyReF89TVTYc3rt9 xA059NsqrQj/U001894cuy2xk2J0GWvFNqgTOGMuGRwrm5AWFnaKCeYwwDAW0JUj6JZbxlDaBXb pFbh87L2ZdIgopHq3rUK9zA7a5srN00/LHzJ/DOcCcTzi6nmnOyfjOMDtq2huAZYzc6p1PPgzOI z+5dCoaQw15lK+m0plw== X-Proofpoint-Spam-Info: AW1haW4tMjYwNzIwMDIzNSBTYWx0ZWRfX5KJcqoJo0kd6 sKePsUN6PpayyxPdRm8k5sjWP19ylLmiGFjo3surkaBzioRzozaiQvtsNavZ9H3MwxRIsZXj0sj 9BlvBXnsz6yduc8AxxXA8u2X0NU09Es= X-Proofpoint-GUID: xj5j8ABTRqGKgo5hDMGmx-NQytJnYyY8 X-Authority-Analysis: v=2.4 cv=SM5ykuvH c=1 sm=1 tr=0 ts=6a5e97ac cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=IkcTkHD0fZMA:10 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=BGMVehrePew0uRRqv7kA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-20_05,2026-07-20_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 lowpriorityscore=0 bulkscore=0 suspectscore=0 adultscore=0 spamscore=0 malwarescore=0 priorityscore=1501 phishscore=0 impostorscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607200235 On 7/20/2026 1:19 PM, Eric Farman wrote: > The routine cp_free() is called to unpin/free any memory once an I/O > is completed successfully, or if cp_prefetch() fails. But if cp_init() > fails, and cp->initialized is not enabled, the same routine cannot be > used to free all the memory. > > An attempt to address this exists in ccwchain_handle_ccw(), where a > single call to ccwchain_free() is made for the currently-processed > CCW segment. But this will leak other segments (created as a result > of a Transfer in Channel) that had been allocated as part of the same > channel program. > > Address this by performing the cleanup outside of the recursive > ccwchain_handle_ccw()/ccwchain_loop_tic() logic. > > Fixes: 8b515be512a2 ("vfio-ccw: Fix memory leak and don't call cp_free in cp_init") > Cc: stable@vger.kernel.org > Cc: Farhan Ali > Signed-off-by: Eric Farman > --- > drivers/s390/cio/vfio_ccw_cp.c | 22 ++++++++++++++++++---- > 1 file changed, 18 insertions(+), 4 deletions(-) > > diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c > index 7561aa7d3e01..086d1b54bdb0 100644 > --- a/drivers/s390/cio/vfio_ccw_cp.c > +++ b/drivers/s390/cio/vfio_ccw_cp.c > @@ -455,9 +455,6 @@ static int ccwchain_handle_ccw(dma32_t cda, struct channel_program *cp) > /* Loop for tics on this new chain. */ > ret = ccwchain_loop_tic(chain, cp); > > - if (ret) > - ccwchain_free(chain); > - > return ret; > } > > @@ -486,6 +483,23 @@ static int ccwchain_loop_tic(struct ccwchain *chain, struct channel_program *cp) > return 0; > } > > +static int ccwchain_build_ccws(dma32_t cda, struct channel_program *cp) > +{ > + struct ccwchain *chain, *temp; > + int ret; > + > + ret = ccwchain_handle_ccw(cda, cp); > + > + if (ret) { > + /* Cleanup if an error occurred */ > + list_for_each_entry_safe(chain, temp, &cp->ccwchain_list, next) { > + ccwchain_free(chain); > + } > + } > + > + return ret; > +} > + > static int ccwchain_fetch_tic(struct ccw1 *ccw, > struct channel_program *cp) > { > @@ -735,7 +749,7 @@ int cp_init(struct channel_program *cp, union orb *orb) > memcpy(&cp->orb, orb, sizeof(*orb)); > > /* Build a ccwchain for the first CCW segment */ > - ret = ccwchain_handle_ccw(orb->cmd.cpa, cp); > + ret = ccwchain_build_ccws(orb->cmd.cpa, cp); > > if (!ret) > cp->initialized = true; The fix looks correct to me and I don't think Sashiko found any issues with this patch (issues identified as pre-existing and i think something this series is trying to fix). Reviewed-by: Farhan Ali Thanks Farhan