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AJvYcCUE2sjCSIKTKRYoB50mCYPeQy89yzpuflUViudQ7bcZjGr4tTzqTs3wIRI6bFJkQ8BDP/nKn+a+VM8pY8c=@vger.kernel.org X-Gm-Message-State: AOJu0Yx3phBQFGxsr6qLFMz6b+djhDQ8KyZsJJAkYAjMgWMdLLSX+h9w s5aBJYudZZvT0bPkodGYhhF2nVJleMgyYfoyI/eublK3OZ01GMP+bkEys0VSCAH7jcT2D1dmmVw YwlIfag== X-Received: from dly16-n1.prod.google.com ([2002:a05:701b:2050:10b0:12a:7f27:56f7]) (user=surenb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7022:6099:b0:119:e569:f874 with SMTP id a92af1059eb24-12ab3045876mr1405563c88.17.1774644912438; Fri, 27 Mar 2026 13:55:12 -0700 (PDT) Date: Fri, 27 Mar 2026 13:54:56 -0700 In-Reply-To: <20260327205457.604224-1-surenb@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260327205457.604224-1-surenb@google.com> X-Mailer: git-send-email 2.53.0.1018.g2bb0e51243-goog Message-ID: <20260327205457.604224-6-surenb@google.com> Subject: [PATCH v6 5/6] mm: use vma_start_write_killable() in process_vma_walk_lock() From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: 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, ljs@kernel.org, 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, imbrenda@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, surenb@google.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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. When queue_pages_range() fails, check whether it failed due to a fatal signal or some other reason and return appropriate error. Suggested-by: Matthew Wilcox Signed-off-by: Suren Baghdasaryan --- fs/proc/task_mmu.c | 12 ++++++------ mm/mempolicy.c | 10 +++++++++- mm/pagewalk.c | 22 +++++++++++++++------- 3 files changed, 30 insertions(+), 14 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index e091931d7ca1..33e5094a7842 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1774,15 +1774,15 @@ static ssize_t clear_refs_write(struct file *file, = const char __user *buf, struct vm_area_struct *vma; enum clear_refs_types type; int itype; - int rv; + int err; =20 if (count > sizeof(buffer) - 1) count =3D sizeof(buffer) - 1; if (copy_from_user(buffer, buf, count)) return -EFAULT; - rv =3D kstrtoint(strstrip(buffer), 10, &itype); - if (rv < 0) - return rv; + err =3D kstrtoint(strstrip(buffer), 10, &itype); + if (err) + return err; type =3D (enum clear_refs_types)itype; if (type < CLEAR_REFS_ALL || type >=3D CLEAR_REFS_LAST) return -EINVAL; @@ -1824,7 +1824,7 @@ static ssize_t clear_refs_write(struct file *file, co= nst char __user *buf, 0, mm, 0, -1UL); mmu_notifier_invalidate_range_start(&range); } - walk_page_range(mm, 0, -1, &clear_refs_walk_ops, &cp); + err =3D walk_page_range(mm, 0, -1, &clear_refs_walk_ops, &cp); if (type =3D=3D CLEAR_REFS_SOFT_DIRTY) { mmu_notifier_invalidate_range_end(&range); flush_tlb_mm(mm); @@ -1837,7 +1837,7 @@ static ssize_t clear_refs_write(struct file *file, co= nst char __user *buf, } put_task_struct(task); =20 - return count; + return err ? : count; } =20 const struct file_operations proc_clear_refs_operations =3D { diff --git a/mm/mempolicy.c b/mm/mempolicy.c index c38a90487531..51f298cfc33b 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -969,6 +969,7 @@ static const struct mm_walk_ops queue_pages_lock_vma_wa= lk_ops =3D { * (a hugetlbfs page or a transparent huge page being counted as 1). * -EIO - a misplaced page found, when MPOL_MF_STRICT specified without MO= VEs. * -EFAULT - a hole in the memory range, when MPOL_MF_DISCONTIG_OK unspeci= fied. + * -EINTR - walk got terminated due to pending fatal signal. */ static long queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long= end, @@ -1545,7 +1546,14 @@ static long do_mbind(unsigned long start, unsigned l= ong len, flags | MPOL_MF_INVERT | MPOL_MF_WRLOCK, &pagelist); =20 if (nr_failed < 0) { - err =3D nr_failed; + /* + * queue_pages_range() might override the original error with -EFAULT. + * Confirm that fatal signals are still treated correctly. + */ + if (fatal_signal_pending(current)) + err =3D -EINTR; + else + err =3D nr_failed; nr_failed =3D 0; } else { vma_iter_init(&vmi, mm, start); diff --git a/mm/pagewalk.c b/mm/pagewalk.c index 3ae2586ff45b..eca7bc711617 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -443,14 +443,13 @@ static inline void process_mm_walk_lock(struct mm_str= uct *mm, mmap_assert_write_locked(mm); } =20 -static inline void process_vma_walk_lock(struct vm_area_struct *vma, - enum page_walk_lock walk_lock) +static int process_vma_walk_lock(struct vm_area_struct *vma, + enum page_walk_lock walk_lock) { #ifdef CONFIG_PER_VMA_LOCK switch (walk_lock) { case PGWALK_WRLOCK: - vma_start_write(vma); - break; + return vma_start_write_killable(vma); case PGWALK_WRLOCK_VERIFY: vma_assert_write_locked(vma); break; @@ -462,6 +461,7 @@ static inline void process_vma_walk_lock(struct vm_area= _struct *vma, break; } #endif + return 0; } =20 /* @@ -505,7 +505,9 @@ int walk_page_range_mm_unsafe(struct mm_struct *mm, uns= igned long start, if (ops->pte_hole) err =3D ops->pte_hole(start, next, -1, &walk); } else { /* inside vma */ - process_vma_walk_lock(vma, ops->walk_lock); + err =3D process_vma_walk_lock(vma, ops->walk_lock); + if (err) + break; walk.vma =3D vma; next =3D min(end, vma->vm_end); vma =3D find_vma(mm, vma->vm_end); @@ -722,6 +724,7 @@ int walk_page_range_vma_unsafe(struct vm_area_struct *v= ma, unsigned long start, .vma =3D vma, .private =3D private, }; + int err; =20 if (start >=3D end || !walk.mm) return -EINVAL; @@ -729,7 +732,9 @@ int walk_page_range_vma_unsafe(struct vm_area_struct *v= ma, unsigned long start, return -EINVAL; =20 process_mm_walk_lock(walk.mm, ops->walk_lock); - process_vma_walk_lock(vma, ops->walk_lock); + err =3D process_vma_walk_lock(vma, ops->walk_lock); + if (err) + return err; return __walk_page_range(start, end, &walk); } =20 @@ -752,6 +757,7 @@ int walk_page_vma(struct vm_area_struct *vma, const str= uct mm_walk_ops *ops, .vma =3D vma, .private =3D private, }; + int err; =20 if (!walk.mm) return -EINVAL; @@ -759,7 +765,9 @@ int walk_page_vma(struct vm_area_struct *vma, const str= uct mm_walk_ops *ops, return -EINVAL; =20 process_mm_walk_lock(walk.mm, ops->walk_lock); - process_vma_walk_lock(vma, ops->walk_lock); + err =3D process_vma_walk_lock(vma, ops->walk_lock); + if (err) + return err; return __walk_page_range(vma->vm_start, vma->vm_end, &walk); } =20 --=20 2.53.0.1018.g2bb0e51243-goog