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Wed, 10 Jun 2026 16:52:47 +0000 (GMT) Received: from p-imbrenda.ehn-de.ibm.com (unknown [9.224.75.30]) by smtpav07.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 10 Jun 2026 16:52:47 +0000 (GMT) From: Claudio Imbrenda To: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org, kvm@vger.kernel.org, linux-s390@vger.kernel.org, borntraeger@de.ibm.com, frankja@linux.ibm.com, david@kernel.org, seiden@linux.ibm.com, nrb@linux.ibm.com, schlameuss@linux.ibm.com, gra@linux.ibm.com Subject: [PATCH v2 2/5] KVM: s390: Fix unlikely race in try_get_locked_pte() Date: Wed, 10 Jun 2026 18:52:44 +0200 Message-ID: <20260610165247.238366-3-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260610165247.238366-1-imbrenda@linux.ibm.com> References: <20260610165247.238366-1-imbrenda@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjEwMDE1NiBTYWx0ZWRfXzaETWQXNQjVo Kkrsut80ayKvvpxAC5PfSYhgQQL5aJG4OLtYlYVuAQlL5mfbNQ3Mwod3Krc2LVKh0ue4hh+4bT5 dlvn9T7t3UNtBosJ0ROQS/mmF7S5PSs//drN14hYL64nJGNq8TuiPZYe0tndS3n6ltKER5zE4gS dqJXzCkZ6wNR+7CAraL9khzofOoiI91wlAeEjylukhWnKB/1V4hgeQfNe0WEbjVrsMXG12TUiO4 XlcN7OPt+mNWAc9Lr1gQYVahF6F4tzne9NURaKqKlFbA2Q5EdJYQLHIi+wdRTIfzAay3jUxfz6U x+sVQ/rBlHk6KgvdN6p1Zc5ioxQfcp5xhrYgXXy/pfNCJJXlpzZHzE4Lb3txDM711crb/qWoaAl jiqUJS2sZOc/FoallJ/Q3JHEg2ZEdbDNToNbCYG8BIEuyy/EPAGdZFnWkqLT1EhSdO8RnDwIzE1 zP5l9cYLXY+0M5iRHyw== X-Authority-Analysis: v=2.4 cv=HvFG3UTS c=1 sm=1 tr=0 ts=6a299666 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VnNF1IyMAAAA:8 a=VwQbUJbxAAAA:8 a=WbevkOawJw57NP_rgK0A:9 X-Proofpoint-ORIG-GUID: -fM0wTlXOOU5yb3Wk79ztVops0_rmc9U X-Proofpoint-GUID: -fM0wTlXOOU5yb3Wk79ztVops0_rmc9U X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-10_03,2026-06-09_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 clxscore=1015 lowpriorityscore=0 adultscore=0 suspectscore=0 spamscore=0 priorityscore=1501 phishscore=0 malwarescore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2605210000 definitions=main-2606100156 Fix an unlikely race in try_get_locked_pte(), which could have happened if puds or pmds get unmapped between the p?dp_get() and p?d_offset() functions. Fixes: 89fa757931dc ("KVM: s390: Avoid potentially sleeping while atomic when zapping pages") Signed-off-by: Claudio Imbrenda CC: stable@vger.kernel.org # 7.1 --- arch/s390/mm/gmap_helpers.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/s390/mm/gmap_helpers.c b/arch/s390/mm/gmap_helpers.c index 1cfe4724fbe2..ee3f37af8aee 100644 --- a/arch/s390/mm/gmap_helpers.c +++ b/arch/s390/mm/gmap_helpers.c @@ -51,15 +51,15 @@ pte_t *try_get_locked_pte(struct mm_struct *mm, unsigned long vmaddr, spinlock_t pgd = pgdp_get(pgdp); if (pgd_none(pgd) || !pgd_present(pgd)) return NULL; - p4dp = p4d_offset(pgdp, vmaddr); + p4dp = p4d_offset_lockless(pgdp, pgd, vmaddr); p4d = p4dp_get(p4dp); if (p4d_none(p4d) || !p4d_present(p4d)) return NULL; - pudp = pud_offset(p4dp, vmaddr); + pudp = pud_offset_lockless(p4dp, p4d, vmaddr); pud = pudp_get(pudp); if (pud_none(pud) || pud_leaf(pud) || !pud_present(pud)) return NULL; - pmdp = pmd_offset(pudp, vmaddr); + pmdp = pmd_offset_lockless(pudp, pud, vmaddr); pmd = pmdp_get_lockless(pmdp); if (pmd_none(pmd) || pmd_leaf(pmd) || !pmd_present(pmd)) return NULL; -- 2.54.0