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b=WVhjgK8G+avnzkT9J4VCT5Ajwxv6Nw9lmhdBxKPu+G2YJKdOL14UdGqe50F4snrsC NVH+vSXSNf1HHbcFR/+f2x9y41eI3bC6CK5CO2EGCT6m+5FeNcEK93Duev8ok+9hLh rltr8Yn1nZgTgXAnHwz02Uom0SDFAYzzp8BUPSDFQcn/9p92NixbjGM6ByVbKiqJl9 l7MArtg/eUk3khx3v5Lz27EaZh5r5yPNSHtay3vvbl5y+Z0qPwyHIEiRtKXYW17sAU 6blLKMq7likwowCKZf94wRZoENiVNmvcVTbnzCe0GL/P4Ss4qa8lEN5FnbCpC1whtw 1O9wc36/6bl2g== Date: Thu, 26 Mar 2026 17:47:25 +0000 From: "Lorenzo Stoakes (Oracle)" 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, 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 Subject: Re: [PATCH v5 5/6] mm: use vma_start_write_killable() in process_vma_walk_lock() Message-ID: <7d558eaa-99d5-4421-9dac-ba17441691f9@lucifer.local> References: <20260326080836.695207-1-surenb@google.com> <20260326080836.695207-6-surenb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260326080836.695207-6-surenb@google.com> X-Stat-Signature: ud1t5m7jg4icry3n45i6c61rs8ff9o3m X-Rspamd-Queue-Id: B62AEA0002 X-Rspam-User: X-Rspamd-Server: rspam03 X-HE-Tag: 1774547248-540903 X-HE-Meta: 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 uWWrqOXC ZNrj1fCdqHCkuQ7LKzrea7fAE1WtEzoVY6f9p4WObc6R4zyg60iJTnwCZN178vl1MN/uuwGpgvxeVjqg4Tk5p4aPtBcW9soLR0MNNs9NMZdKaDGr/pgqSaXZa2X9t+wN/Klh00Kyu9QJblT9yd2QoMrM5hNqDuMWXEcAJgQ/mZMTXBnlFavTsI9a2Tzc2CPa+Tv94sO/NOo1uq6D1NRB9i7b4mwcY+nwhJDi3m+aG8CA6mGHSSBg/FUolyqYIJASy/7ZVjBEf4zsC8J7eV8c3wnF2yhLdrA9ylS0QrMWNmSoc8gsv6++/t4AACCQScQHvjCsMoXErOBHf7KlRnKyzU562fTEBa/4qftxPS9nhxDX44f9u0BfIY6fiSTh4F8n6iVSr88h4zHcLnriDsQdhETdxPpUG0ZmIovNBU+Vvb8MQ4Vge2kEAjhDbMw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Mar 26, 2026 at 01:08:35AM -0700, 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. > > Suggested-by: Matthew Wilcox > Signed-off-by: Suren Baghdasaryan LGTM, so: Reviewed-by: Lorenzo Stoakes (Oracle) > --- > fs/proc/task_mmu.c | 12 ++++++------ > mm/mempolicy.c | 1 + > mm/pagewalk.c | 22 +++++++++++++++------- > 3 files changed, 22 insertions(+), 13 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; > > if (count > sizeof(buffer) - 1) > count = sizeof(buffer) - 1; > if (copy_from_user(buffer, buf, count)) > return -EFAULT; > - rv = kstrtoint(strstrip(buffer), 10, &itype); > - if (rv < 0) > - return rv; > + err = kstrtoint(strstrip(buffer), 10, &itype); > + if (err) > + return err; > type = (enum clear_refs_types)itype; > if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST) > return -EINVAL; > @@ -1824,7 +1824,7 @@ static ssize_t clear_refs_write(struct file *file, const 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 = walk_page_range(mm, 0, -1, &clear_refs_walk_ops, &cp); > if (type == 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, const char __user *buf, > } > put_task_struct(task); > > - return count; > + return err ? : count; > } > > const struct file_operations proc_clear_refs_operations = { > diff --git a/mm/mempolicy.c b/mm/mempolicy.c > index c38a90487531..336753a4b2b2 100644 > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -969,6 +969,7 @@ static const struct mm_walk_ops queue_pages_lock_vma_walk_ops = { > * (a hugetlbfs page or a transparent huge page being counted as 1). > * -EIO - a misplaced page found, when MPOL_MF_STRICT specified without MOVEs. > * -EFAULT - a hole in the memory range, when MPOL_MF_DISCONTIG_OK unspecified. > + * -EINTR - walk got terminated due to pending fatal signal. > */ > static long > queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end, > 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_struct *mm, > mmap_assert_write_locked(mm); > } > > -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; > } > > /* > @@ -505,7 +505,9 @@ int walk_page_range_mm_unsafe(struct mm_struct *mm, unsigned long start, > if (ops->pte_hole) > err = ops->pte_hole(start, next, -1, &walk); > } else { /* inside vma */ > - process_vma_walk_lock(vma, ops->walk_lock); > + err = process_vma_walk_lock(vma, ops->walk_lock); > + if (err) > + break; > walk.vma = vma; > next = min(end, vma->vm_end); > vma = find_vma(mm, vma->vm_end); > @@ -722,6 +724,7 @@ int walk_page_range_vma_unsafe(struct vm_area_struct *vma, unsigned long start, > .vma = vma, > .private = private, > }; > + int err; > > if (start >= end || !walk.mm) > return -EINVAL; > @@ -729,7 +732,9 @@ int walk_page_range_vma_unsafe(struct vm_area_struct *vma, unsigned long start, > return -EINVAL; > > process_mm_walk_lock(walk.mm, ops->walk_lock); > - process_vma_walk_lock(vma, ops->walk_lock); > + err = process_vma_walk_lock(vma, ops->walk_lock); > + if (err) > + return err; > return __walk_page_range(start, end, &walk); > } > > @@ -752,6 +757,7 @@ int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops, > .vma = vma, > .private = private, > }; > + int err; > > if (!walk.mm) > return -EINVAL; > @@ -759,7 +765,9 @@ int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops, > return -EINVAL; > > process_mm_walk_lock(walk.mm, ops->walk_lock); > - process_vma_walk_lock(vma, ops->walk_lock); > + err = process_vma_walk_lock(vma, ops->walk_lock); > + if (err) > + return err; > return __walk_page_range(vma->vm_start, vma->vm_end, &walk); > } > > -- > 2.53.0.1018.g2bb0e51243-goog >