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AJvYcCUSbg8Ivh7gLVeMNNps37jjJe7Tc/YwRJT/CY8T+tpaC2RuAPx+p4gfCDdOobG3e41ZwR5islHqDA==@kvack.org X-Gm-Message-State: AOJu0YwacJL1tpTtE4AebbU+BQEpKNeSAOAVx1lw1SkhGRyuZYpT2PSY j0vLKXpojdNFXJz82OlHGRfFpOZl/5iiOhUf1Va8SiJWhT+1OdRi5BaKZUM9PIvo6ocfsvgDXrY yOVjKcSBWd3dTyWnPMzhplJ4PWNfbK2kfQ6HRJHNv X-Gm-Gg: ATEYQzy+i9Ckb9CCIjS6WLBsu1X0rNnva9rx47l/01qMEFpmIfaBxLjOvIPMQ6bjqZm MtuhD8BV7BdWwOp+eA1l5wf2MiOmpQGSBPUK8+Mh9ZzsQCgBLkvvAde70rH/+UHhkiCegcZlMYN zWFthhxqPOFin8kjT0MqboW1sEZHQqLFY16cxhm/uOnlAfoeRQ4QHabBMSx55jm53XoeMOhkJBY XyEkUqV79HZ9lqdzebUoUgXJ/bfdwqOdXy3j2PxwTfTEzJ4ezANnCyc1ZfmHoCglYDSUsgMHXuW ikJCX4FA8vVLzebir3blao5hVWYMqOeOqx0rTa3od4nqTUH0 X-Received: by 2002:a05:622a:15d1:b0:501:4eae:dbfc with SMTP id d75a77b69052e-507454fc6c1mr12936811cf.5.1772130300634; Thu, 26 Feb 2026 10:25:00 -0800 (PST) MIME-Version: 1.0 References: <20260226070609.3072570-1-surenb@google.com> <20260226070609.3072570-4-surenb@google.com> <20260226191007.409a7a21@p-imbrenda> In-Reply-To: <20260226191007.409a7a21@p-imbrenda> From: Suren Baghdasaryan Date: Thu, 26 Feb 2026 10:24:49 -0800 X-Gm-Features: AaiRm52wFdTJC6YvOb26vvaOOFR294VpLCUuG2iciIW7CwkMabryiSXuJJdbEug Message-ID: Subject: Re: [PATCH v3 3/3] mm: use vma_start_write_killable() in process_vma_walk_lock() To: Claudio Imbrenda 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 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: A6164A000A X-Stat-Signature: huwrsg4ufdf16d14iou1g89apmrbioab X-Rspam-User: X-HE-Tag: 1772130302-454783 X-HE-Meta: U2FsdGVkX1+Edjkpu3E3JOM2GPRKCNXKxWTiznkxLgMSLwgN8M1MiWvJpRowMA+m2L93b4wiyKtKyXQ81bTS2lTAxUQjGz+G2kRGo8sX7lkC+xCKZP6bi6sct5dW3EFeqC16EmIgOAsYVENPV2vnAwC9kHuJ8wtKqBcMFpQD/jZWUXWCw1JE47H6adw/nD8tgF99p8JmJDuOfiDgxJSDksOry54Os1SqzLeO38KC7BfscUvgCikjfIV9MecNb0aXqxr5fMpgPSrICCtnEzyZ5xk2cwz4cdcoWIvwwwXOTrMIwh1DfuEs5p9ev7zRungawsAuojlUq3U59ETsrAcfZibNLowSJvS6iT3QbIp2HCHoO6oMC3c3MEePgkLej2qRNwltlJLTn7kD7RUg2+RPGEZ+MRXeJCUwQ1uQcVMdvukGXKggHEUs+zrmMHQAVacuqE+h+fj665xFz6TK/7HDBhum0TUt5QAcUDdq1Efrn6NEz4xxIh+5VSIVDw8XVVYBVtY4pHrLyMhKXLM+sh6SUwRvXSX5eiACDTQqFmjFmp5+Dv0dORRAD2hkp4YSC2dwF5Yzif6cCcCJaWYzIT7nWnqcDCDyhIlE9XhHGHkbhhmG1ZF86M0w/GyvSyoRZkpkzP5oxmCLmLEK+HvZMN3l1Hr2eCQlKR9eZyn6eSf2O+oBiTAYv+1u5Zhr+EDtMFGLpIw2YOBgPSJjiNz+5w0yORh2+SAlqtqd363QJaQX4dEb+egoXQ4gDHECQytdLcVHV9VBlYb20Z9gavJuM0CDJ5b97hHseOqRe+h0D2u2rh3GQ38IcPzcGXB260ZLwpeery+Dzx2fYjEmn/FRGQhcD30rAPz4kgaC9HXA8mAAjDHobN/arcgyg15IAPNp33gDuAfOyiIFULmvmumzP05lQdBXjpToZ2IGbIEOVKUSJQ1u5NDuYklnrWIt+zGjRf3MdJfg+vgpFpSG6X19HRA kvCfI3NT gjSFT/D61B+g4rN8qpw0YuS/Z2iegLII9Brg9X2SGvBmNcpfKNx3APxj8d8rJeXEOFO2WpOQ/+gkorAe/JOFVXrQnRfpQ2K/TW+CfM/3beqPm3+eUsdwEXbQdl0VLWmNun31IPFLMq3gaXanHp559dIKRxQyF87kXEgvvnd4O0DkG8aMfy4ntjRzgHrpSj7fCiDOoXR7f7dRj5cjJcztEkdKEsxFWqPvNAY66DIyZc17EsZrTY1VzcRoDsGifRguLfTpV1eJIYe3lDEPTsfVG20tFEBXUuHDcF6xwXkVD2akpGjuLiav4YAFCpURbYEkVP5cliVCTo3ktJc1cqlGXdikGMZluLTqWzgES9SKxZ4Y8dxwK5QdxDrQYC8SeyQ7H78cEmrvnczh6PQi41CFBSqmG2A== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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: > > > 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 =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(arg= s))) { > > r =3D -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? Correct, it would happen if the process has a pending fatal signal (like SIGKILL) in its signal queue. > > [...]