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Thu, 26 Feb 2026 18:10:14 +0000 Received: from smtpav05.fra02v.mail.ibm.com (smtpav05.fra02v.mail.ibm.com [10.20.54.104]) by smtprelay07.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 61QIAAwk42991898 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 26 Feb 2026 18:10:10 GMT Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2C5B620043; Thu, 26 Feb 2026 18:10:10 +0000 (GMT) Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A613320040; Thu, 26 Feb 2026 18:10:09 +0000 (GMT) Received: from p-imbrenda (unknown [9.52.223.175]) by smtpav05.fra02v.mail.ibm.com (Postfix) with SMTP; Thu, 26 Feb 2026 18:10:09 +0000 (GMT) Date: Thu, 26 Feb 2026 19:10:07 +0100 From: Claudio Imbrenda To: Suren Baghdasaryan Cc: akpm@linux-foundation.org, willy@infradead.org, david@kernel.org, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, gourry@gourry.net, ying.huang@linux.alibaba.com, apopple@nvidia.com, lorenzo.stoakes@oracle.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, vbabka@suse.cz, jannh@google.com, rppt@kernel.org, mhocko@suse.com, pfalcato@suse.de, kees@kernel.org, maddy@linux.ibm.com, npiggin@gmail.com, mpe@ellerman.id.au, chleroy@kernel.org, borntraeger@linux.ibm.com, frankja@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, svens@linux.ibm.com, gerald.schaefer@linux.ibm.com, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org Subject: Re: [PATCH v3 3/3] mm: use vma_start_write_killable() in process_vma_walk_lock() Message-ID: <20260226191007.409a7a21@p-imbrenda> In-Reply-To: <20260226070609.3072570-4-surenb@google.com> References: <20260226070609.3072570-1-surenb@google.com> <20260226070609.3072570-4-surenb@google.com> Organization: IBM X-Mailer: Claws Mail 4.3.1 (GTK 3.24.49; x86_64-redhat-linux-gnu) X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-ORIG-GUID: CtrnfnLFeGbNILvMxH4zz7_6vXcy1bo2 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMjI2MDE2NSBTYWx0ZWRfX92/iJsyzGWX+ U7gNleqecboFJWTHpna/+exChG3YePLWbT7HIINpkqg0RRcbAghOgu83/JdENcOYjyMxHXyYS2J vxq09Edt50L8rapeL1iGqQfXep6UdFtEScs6PLrjliHJTfK4HkCtLV1f5gYqnr4+oR+P/TmrBrJ WHUPRr898gbzAFY0BpdSk4/GWwqKBJ07z/9d2A3JTukzTerEs7+5ySYw7XMrM/MTFa6foacNTwu ZzwE1fe97JUOUH3DNbY21+30YHBz0ECn7fkHHJ4mRtDcI9n0YT/WOppk/oEf16FvL4+a4QS/5xY UAk4/2ujObMmGbT5ewiKuYjsEYSWdCs29SxYLJCCj4/1z0zdDKNhZ7ATf/bTOCeEEIGocCE7sZy PwQ4UxojBvq7LC4FCsLrkANEzgg4tXzL50hIzKkCGgm65w87ImnGgtlyXd+XZXRjtxPBhS5EBYQ NQ7T/7hz36hqMdZ4aaw== X-Authority-Analysis: v=2.4 cv=eNceTXp1 c=1 sm=1 tr=0 ts=69a08c87 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=kj9zAlcOel0A:10 a=HzLeVaNsDn8A:10 a=VkNPw1HP01LnGYTKEx00:22 a=Mpw57Om8IfrbqaoTuvik:22 a=GgsMoib0sEa3-_RKJdDe:22 a=1XWaLZrsAAAA:8 a=8MrrMA2wyEC7cuUn5CwA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-GUID: 5vfp8VXyeBQAaEvJC7GasClW74sWeMkd X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-02-26_02,2026-02-26_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1011 priorityscore=1501 phishscore=0 suspectscore=0 adultscore=0 bulkscore=0 lowpriorityscore=0 malwarescore=0 impostorscore=0 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2601150000 definitions=main-2602260165 On Wed, 25 Feb 2026 23:06:09 -0800 Suren Baghdasaryan wrote: > Replace vma_start_write() with vma_start_write_killable() when > process_vma_walk_lock() is used with PGWALK_WRLOCK option. > Adjust its direct and indirect users to check for a possible error > and handle it. Ensure users handle EINTR correctly and do not ignore > it. > > Signed-off-by: Suren Baghdasaryan > --- > arch/s390/kvm/kvm-s390.c | 2 +- > fs/proc/task_mmu.c | 5 ++++- > mm/mempolicy.c | 14 +++++++++++--- > mm/pagewalk.c | 20 ++++++++++++++------ > mm/vma.c | 22 ++++++++++++++-------- > mm/vma.h | 6 ++++++ > 6 files changed, 50 insertions(+), 19 deletions(-) > > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index 7a175d86cef0..337e4f7db63a 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -2948,7 +2948,7 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) > } > /* must be called without kvm->lock */ > r = kvm_s390_handle_pv(kvm, &args); > - if (copy_to_user(argp, &args, sizeof(args))) { > + if (r != -EINTR && copy_to_user(argp, &args, sizeof(args))) { > r = -EFAULT; > break; > } can you very briefly explain how we can end up with -EINTR here? do I understand correctly that -EINTR is possible here only if the process is being killed? 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