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Fri, 4 Sep 2026 06:06:52 +0000 (GMT) From: Claudio Imbrenda To: pbonzini@redhat.com Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, frankja@linux.ibm.com, borntraeger@de.ibm.com Subject: [GIT PULL v1 08/11] KVM: s390: Fix race in _destroy_pages_crste() Date: Fri, 4 Sep 2026 08:06:44 +0200 Message-ID: <20260904060647.562443-9-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904060647.562443-1-imbrenda@linux.ibm.com> References: <20260904060647.562443-1-imbrenda@linux.ibm.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=PPc/P/qC c=1 sm=1 tr=0 ts=6a9a6003 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VnNF1IyMAAAA:8 a=N6WJw_kgbt6RfBQfb4YA:9 X-Proofpoint-GUID: xCmi_KnKQxw3wN6lPpOun8O60xgg0pfi X-Proofpoint-ORIG-GUID: xCmi_KnKQxw3wN6lPpOun8O60xgg0pfi X-Proofpoint-Spam-Info: AW1haW4tMjYwOTA0MDA1NCBTYWx0ZWRfXxHet7IYxTKGz fFjFlVbagVLaYsXYvDXtXSUwKCY4uZlfsbtRTrRqaAY/rM3/LGLA+8rESQ4ctUsUb/6PHom//8R 7f/01O1fKEts5Mgk6lxQllQOJ7UA4cc= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTA0MDA1NCBTYWx0ZWRfX9qOndnIfQQz5 HJ2bzEHr1IlFopWpFgk2/U3CXdLgdLQp0D1iDKhF5qVICBqRGzR7n9+l5D6TMgUqfcxTET/Wfgz 9kldgRvNjDScV10Zqt4MdZz1u9K8PTd2AvrAeEpNO9HwfMO7UVYAt9FOpApI9dijh6ga19BYNwY 9V2G+odWtLXk5kZsRpqE8zOjzZTk23LrmkKdbYjjChfPtOX6O7nfcJXd8keSk6UyiccnMD5ttty q4RUPIBbFOKpJfMTqIjNd/B08HauJIqbrS9J8SAvWtcBeVmcktrdugaPRHE9WREDA/l/0eXhpT2 vLzcbvOUP8XQgchJYzmHIKD15zn6dcxFn+VSAwrKrxH1qy/b2yY2A2CZvw7/1tshQm3ZnqJJAfS spe9/kqRkiX2w/4CLdl2Gy1y3G2ZA0vPc4dbko8aVZYQLCpDvQqfMlHKZCZQUDqivhER7sOxfch JsJjEdU1V9vVWrE91nw== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-04_02,2026-09-03_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 phishscore=0 adultscore=0 suspectscore=0 bulkscore=0 spamscore=0 priorityscore=1501 impostorscore=0 malwarescore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2609040054 Use READ_ONCE() in _destroy_pages_crste() to read the crste, avoid dereferencing the pointer multiple times. Fixes: a2c17f9270cc ("KVM: s390: New gmap code") Signed-off-by: Claudio Imbrenda Message-ID: <20260828115439.145885-9-imbrenda@linux.ibm.com> --- arch/s390/kvm/gmap/gmap.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/s390/kvm/gmap/gmap.c b/arch/s390/kvm/gmap/gmap.c index 4968330e9553..3f3fa864cc36 100644 --- a/arch/s390/kvm/gmap/gmap.c +++ b/arch/s390/kvm/gmap/gmap.c @@ -994,11 +994,13 @@ static long _destroy_pages_pte(union pte *ptep, gfn_t gfn, gfn_t next, struct da static long _destroy_pages_crste(union crste *crstep, gfn_t gfn, gfn_t next, struct dat_walk *walk) { phys_addr_t origin, cur, end; + union crste crste; - if (!crstep->h.fc || !crstep->s.fc1.pr) + crste = READ_ONCE(*crstep); + if (!crste.h.fc || !crste.s.fc1.pr) return 0; - origin = crste_origin_large(*crstep); + origin = crste_origin_large(crste); cur = ((max(gfn, walk->start) - gfn) << PAGE_SHIFT) + origin; end = ((min(next, walk->end) - gfn) << PAGE_SHIFT) + origin; for ( ; cur < end; cur += PAGE_SIZE) -- 2.55.0