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Wed, 7 Oct 2026 11:41:59 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.87.85.9]) by smtpav06.fra02v.mail.ibm.com (Postfix) with SMTP; Wed, 7 Oct 2026 11:41:59 +0000 (GMT) Received: by tuxmaker.boeblingen.de.ibm.com (Postfix, from userid 55669) id 8DF56160A46; Wed, 07 Oct 2026 13:41:58 +0200 (CEST) From: Alexander Gordeev To: Gerald Schaefer , Heiko Carstens , Christian Borntraeger , Vasily Gorbik , Claudio Imbrenda , Andrey Ryabinin Cc: Muhammad Usama Anjum , linux-s390@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com Subject: [PATCH v8 10/15] s390/mm: Cleanup pXXp_flush_lazy() routines Date: Wed, 7 Oct 2026 13:41:53 +0200 Message-ID: <964adeedfd20d4dbcc9a6341f57ec7aaac6c6adc.1791365932.git.agordeev@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-ORIG-GUID: -rbscqX-jlGyEG1AjE7JMIlN7cz_bdzY X-Proofpoint-Spam-Info: AW1haW4tMjYxMDA3MDA0NiBTYWx0ZWRfXyf4C5x7d7mrL bQiLAzVu04XuOI8WvL7nmG0N+YoIn5yGAb5tfzuZ0S0SElWCkCSIe/THZKu1FUKBatCJ6Sc0Div WkLEMz4aWC7tnp7bx05YHtTARMm/S1g= X-Proofpoint-GUID: 7uuXtvi7iNGngb0u1UfDGoO-xLVZzrkC X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMDA3MDA0NiBTYWx0ZWRfX52B+fyo9B4lN SM2fiicShdIOuyWmcSOKzZX5jWY1uQkPzXQ7FXWgKEZjCwsq144DsEoixzr4mBYl3ZxufAar/Lp ODC5K1FYtsocbx9flsyL6wTACVw4J9Yt3a6Wo4uiVd0mTUu977MG42Hv5n6xwNi7NfD3ILsExqA AUOV3WysEdy+YjDOFWmNtybc2e/x7YqtoYaJLl0t2GSfK5/PP7/0+m7DQnZB2u7p36Rn/jongr/ rYwyrJ49reXkz0ZISy8iWXbVJNKk8NGeuCgA+UYX/5XkHUjfvyFXzrKlU3vPeTejnTWTr88LS2m sL65ipV1IldtB6w8HB8o2R4dlvP1cPCPd6J26+c5NI7vHqHEm0phCKkUPyv3gPWZ+3pPRkrBcwN gx0rZ9CN0VV0k0Yur8pyM4zxqrL5ZqoHZ0eTsBEjJyKhoTnNs+ZxsZ4mjrS9tfh9+/mJjWe6hHT 33Ll/46Szzub02b1UyQ== X-Authority-Analysis: v=2.4 cv=fM2sTpae c=1 sm=1 tr=0 ts=6ac6300c cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=660iZSQnnn4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VnNF1IyMAAAA:8 a=jYzbKW4fU5_uXXChEaUA:9 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=2026-10-07_04,2026-10-06_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 bulkscore=0 priorityscore=1501 spamscore=0 lowpriorityscore=0 phishscore=0 adultscore=0 malwarescore=0 clxscore=1015 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2609040000 definitions=main-2610070046 Avoid unnecessary pgtable entry read in ptep_flush_lazy() and pmdp_flush_lazy() routines. Use the already obtained value of a pgtable entry instead of dereferencing it again. It might appear that the optimized out second dereferencing happens under mm_context_t::flush_count lock and therefore a race condition is possible. However, both routines write invalid entry bits to the pgtable entries and therefore no reader is allowed to interpret the rest of the value afterwards. Signed-off-by: Alexander Gordeev --- arch/s390/mm/pgtable.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 4acd8b140c4b..da076928b63b 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -107,7 +107,7 @@ static inline pte_t ptep_flush_lazy(struct mm_struct = *mm, atomic_inc(&mm->context.flush_count); if (cpumask_equal(&mm->context.cpu_attach_mask, cpumask_of(smp_processor_id()))) { - set_pte(ptep, set_pte_bit(*ptep, __pgprot(_PAGE_INVALID))); + set_pte(ptep, set_pte_bit(old, __pgprot(_PAGE_INVALID))); mm->context.flush_mm =3D 1; } else ptep_ipte_global(mm, addr, ptep, nodat); @@ -227,7 +227,7 @@ static inline pmd_t pmdp_flush_lazy(struct mm_struct = *mm, atomic_inc(&mm->context.flush_count); if (cpumask_equal(&mm->context.cpu_attach_mask, cpumask_of(smp_processor_id()))) { - set_pmd(pmdp, set_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_INVALID))); + set_pmd(pmdp, set_pmd_bit(old, __pgprot(_SEGMENT_ENTRY_INVALID))); mm->context.flush_mm =3D 1; } else { pmdp_idte_global(mm, addr, pmdp); --=20 2.53.0