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Fri, 27 Feb 2026 08:57:24 +0000 Received: from smtpav07.fra02v.mail.ibm.com (smtpav07.fra02v.mail.ibm.com [10.20.54.106]) by smtprelay04.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 61R8vJo814090732 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 27 Feb 2026 08:57:20 GMT Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D71652004B; Fri, 27 Feb 2026 08:57:19 +0000 (GMT) Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 49CE620040; Fri, 27 Feb 2026 08:57:16 +0000 (GMT) Received: from p-imbrenda (unknown [9.111.69.15]) by smtpav07.fra02v.mail.ibm.com (Postfix) with SMTP; Fri, 27 Feb 2026 08:57:16 +0000 (GMT) Date: Fri, 27 Feb 2026 09:57:14 +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: <20260227095714.5e69a0a8@p-imbrenda> In-Reply-To: References: <20260226070609.3072570-1-surenb@google.com> <20260226070609.3072570-4-surenb@google.com> <20260226191007.409a7a21@p-imbrenda> 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=UTF-8 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMjI3MDA3MyBTYWx0ZWRfX9WncEKIsvtkE 93BCkSDioR3viSI4k8M8ER0no2D2zADEGoLWX0KPQp0RA8BsPJbCrfq2KNwhRaeVWK9DAn3UOd6 JAAx02zp+y9sAZSn4DLDrb3m80HWoUwQ3XZbkAc/WY4whBIPdkpq5++S1OS1U/BZL1YM5xtJRtL asZKx6fRd45Z4dwVYGheVX0JssABTlQnZcPMUUlLPHlLa2PGtc+gWSwVlWd/LbyzyJTu5/eCRQv ZD0ydFAWHEbM9dSGMVwbFmFBk6I11/cjfskqj1vi3sWYi9ExPCWFV8MocD36VLDGxyr7Hgvw95a oNSV4Q1Wk5+LBR+205t5wPH9duGWR6eo7a84XSUaM2JtRffZshKV0ovn8RzJA32bUOqSp/TehRx vmDqLHCgdsnyiO0l67/DgUsWIDjh+fag6Xuw/2WaA0DTHK1m/3W1tSm4sGSr6C6KPXPZdDprF1U j1k9+KMGXV8XsaOEoIg== X-Proofpoint-ORIG-GUID: ajegLXIpD6Zt7S3-2yKIDNzKpDYqMOPu X-Authority-Analysis: v=2.4 cv=F9lat6hN c=1 sm=1 tr=0 ts=69a15c75 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=IkcTkHD0fZMA:10 a=HzLeVaNsDn8A:10 a=VkNPw1HP01LnGYTKEx00:22 a=Mpw57Om8IfrbqaoTuvik:22 a=GgsMoib0sEa3-_RKJdDe:22 a=1XWaLZrsAAAA:8 a=VnNF1IyMAAAA:8 a=Ch0MJLqadWv443iAyyUA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: co2lSwi4qVEs7Dzgf2PvZ6JwEnc7YSIK 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=2026-02-27_01,2026-02-26_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 phishscore=0 bulkscore=0 adultscore=0 spamscore=0 clxscore=1015 suspectscore=0 malwarescore=0 lowpriorityscore=0 priorityscore=1501 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2601150000 definitions=main-2602270073 On Thu, 26 Feb 2026 10:24:49 -0800 Suren Baghdasaryan wrote: > On Thu, Feb 26, 2026 at 10:10=E2=80=AFAM Claudio Imbrenda > wrote: > > > > On Wed, 25 Feb 2026 23:06:09 -0800 > > Suren Baghdasaryan wrote: > > =20 > > > 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, unsign= ed int ioctl, unsigned long arg) > > > } > > > /* must be called without kvm->lock */ > > > r =3D kvm_s390_handle_pv(kvm, &args); > > > - if (copy_to_user(argp, &args, sizeof(args))) { > > > + if (r !=3D -EINTR && copy_to_user(argp, &args, sizeof(a= rgs))) { > > > r =3D -EFAULT; > > > break; > > > } =20 > > > > 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? =20 >=20 > Correct, it would happen if the process has a pending fatal signal > (like SIGKILL) in its signal queue. >=20 > > > > [...] =20 Acked-by: Claudio Imbrenda