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AJvYcCXEIXx4ubz4wIbNZLJKIxPonMEbT0nZptil9cTU7dUbJCgDtLJzXIFDAhEfejoi59GJ0OeyKROxAA==@kvack.org X-Gm-Message-State: AOJu0YyQsY2m1EMM36vF/u6xJGT8pu2jqTPcR0UcqwJ7umXUT+RWxUSi w5VQMQaVfx2p9edr9DL9kl/ETG3FqzkkAES6/m28yITPitpvQP3g76ckyAtmEJI/1VyUE7swnh5 HTQPMZQ== X-Received: from dlbts5-n2.prod.google.com ([2002:a05:7022:b045:20b0:12a:7c27:8e88]) (user=surenb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7022:2591:b0:127:5c54:a124 with SMTP id a92af1059eb24-12a726db50fmr3890614c88.31.1774158197165; Sat, 21 Mar 2026 22:43:17 -0700 (PDT) Date: Sat, 21 Mar 2026 22:43:06 -0700 In-Reply-To: <20260322054309.898214-1-surenb@google.com> Mime-Version: 1.0 References: <20260322054309.898214-1-surenb@google.com> X-Mailer: git-send-email 2.53.0.1018.g2bb0e51243-goog Message-ID: <20260322054309.898214-3-surenb@google.com> Subject: [PATCH v4 2/4] mm: replace vma_start_write() with vma_start_write_killable() 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, 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, surenb@google.com, "Ritesh Harjani (IBM)" Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 86BA81C000F X-Stat-Signature: awpws4f16dnu7psg9guepc3a4q9yxzrw X-Rspam-User: X-HE-Tag: 1774158198-830805 X-HE-Meta: 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 3LiYl3uB 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Now that we have vma_start_write_killable() we can replace most of the vma_start_write() calls with it, improving reaction time to the kill signal. There are several places which are left untouched by this patch: 1. free_pgtables() because function should free page tables even if a fatal signal is pending. 2. process_vma_walk_lock(), which requires changes in its callers and will be handled in the next patch. 3. userfaultd code, where some paths calling vma_start_write() can handle EINTR and some can't without a deeper code refactoring. 4. mpol_rebind_mm() which is used by cpuset controller for migrations and operates on a remote mm. Incomplete operations here would result in an inconsistent cgroup state. 5. vm_flags_{set|mod|clear} require refactoring that involves moving vma_start_write() out of these functions and replacing it with vma_assert_write_locked(), then callers of these functions should lock the vma themselves using vma_start_write_killable() whenever possible. In a number of places we now lock VMA earlier than before to avoid doing work and undoing it later if a fatal signal is pending. This is safe because the moves are happening within sections where we already hold the mmap_write_lock, so the moves do not change the locking order relative to other kernel locks. Suggested-by: Matthew Wilcox Signed-off-by: Suren Baghdasaryan Reviewed-by: Ritesh Harjani (IBM) # powerpc --- arch/powerpc/kvm/book3s_hv_uvmem.c | 5 +- mm/khugepaged.c | 5 +- mm/madvise.c | 4 +- mm/memory.c | 2 + mm/mempolicy.c | 12 ++- mm/mlock.c | 28 +++++-- mm/mprotect.c | 5 +- mm/mremap.c | 4 +- mm/vma.c | 117 +++++++++++++++++++++-------- mm/vma_exec.c | 6 +- 10 files changed, 142 insertions(+), 46 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c index 5fbb95d90e99..0a28b48a46b8 100644 --- a/arch/powerpc/kvm/book3s_hv_uvmem.c +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c @@ -410,7 +410,10 @@ static int kvmppc_memslot_page_merge(struct kvm *kvm, ret = H_STATE; break; } - vma_start_write(vma); + if (vma_start_write_killable(vma)) { + ret = H_STATE; + break; + } /* Copy vm_flags to avoid partial modifications in ksm_madvise */ vm_flags = vma->vm_flags; ret = ksm_madvise(vma, vma->vm_start, vma->vm_end, diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 4b0e59c7c0e6..e2f263076084 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1159,7 +1159,10 @@ static enum scan_result collapse_huge_page(struct mm_struct *mm, unsigned long a if (result != SCAN_SUCCEED) goto out_up_write; /* check if the pmd is still valid */ - vma_start_write(vma); + if (vma_start_write_killable(vma)) { + result = SCAN_FAIL; + goto out_up_write; + } result = check_pmd_still_valid(mm, address, pmd); if (result != SCAN_SUCCEED) goto out_up_write; diff --git a/mm/madvise.c b/mm/madvise.c index 69708e953cf5..feaa16b0e1dc 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -175,7 +175,9 @@ static int madvise_update_vma(vm_flags_t new_flags, madv_behavior->vma = vma; /* vm_flags is protected by the mmap_lock held in write mode. */ - vma_start_write(vma); + if (vma_start_write_killable(vma)) + return -EINTR; + vma->flags = new_vma_flags; if (set_new_anon_name) return replace_anon_vma_name(vma, anon_name); diff --git a/mm/memory.c b/mm/memory.c index 68cc592ff0ba..b930459e32ec 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -366,6 +366,8 @@ void free_pgd_range(struct mmu_gather *tlb, * page tables that should be removed. This can differ from the vma mappings on * some archs that may have mappings that need to be removed outside the vmas. * Note that the prev->vm_end and next->vm_start are often used. + * We don't use vma_start_write_killable() because page tables should be freed + * even if the task is being killed. * * The vma_end differs from the pg_end when a dup_mmap() failed and the tree has * unrelated data to the mm_struct being torn down. diff --git a/mm/mempolicy.c b/mm/mempolicy.c index e5528c35bbb8..929e843543cf 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1784,7 +1784,8 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le return -EINVAL; if (end == start) return 0; - mmap_write_lock(mm); + if (mmap_write_lock_killable(mm)) + return -EINTR; prev = vma_prev(&vmi); for_each_vma_range(vmi, vma, end) { /* @@ -1801,13 +1802,20 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le err = -EOPNOTSUPP; break; } + /* + * Lock the VMA early to avoid extra work if fatal signal + * is pending. + */ + if (vma_start_write_killable(vma)) { + err = -EINTR; + break; + } new = mpol_dup(old); if (IS_ERR(new)) { err = PTR_ERR(new); break; } - vma_start_write(vma); new->home_node = home_node; err = mbind_range(&vmi, vma, &prev, start, end, new); mpol_put(new); diff --git a/mm/mlock.c b/mm/mlock.c index 8c227fefa2df..efbb9c783f25 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -419,8 +419,10 @@ static int mlock_pte_range(pmd_t *pmd, unsigned long addr, * * Called for mlock(), mlock2() and mlockall(), to set @vma VM_LOCKED; * called for munlock() and munlockall(), to clear VM_LOCKED from @vma. + * + * Return: 0 on success, -EINTR if fatal signal is pending. */ -static void mlock_vma_pages_range(struct vm_area_struct *vma, +static int mlock_vma_pages_range(struct vm_area_struct *vma, unsigned long start, unsigned long end, vma_flags_t *new_vma_flags) { @@ -442,7 +444,9 @@ static void mlock_vma_pages_range(struct vm_area_struct *vma, */ if (vma_flags_test(new_vma_flags, VMA_LOCKED_BIT)) vma_flags_set(new_vma_flags, VMA_IO_BIT); - vma_start_write(vma); + if (vma_start_write_killable(vma)) + return -EINTR; + vma_flags_reset_once(vma, new_vma_flags); lru_add_drain(); @@ -453,6 +457,7 @@ static void mlock_vma_pages_range(struct vm_area_struct *vma, vma_flags_clear(new_vma_flags, VMA_IO_BIT); vma_flags_reset_once(vma, new_vma_flags); } + return 0; } /* @@ -506,11 +511,13 @@ static int mlock_fixup(struct vma_iterator *vmi, struct vm_area_struct *vma, */ if (vma_flags_test(&new_vma_flags, VMA_LOCKED_BIT) && vma_flags_test(&old_vma_flags, VMA_LOCKED_BIT)) { + ret = vma_start_write_killable(vma); + if (ret) + goto out; /* No work to do, and mlocking twice would be wrong */ - vma_start_write(vma); vma->flags = new_vma_flags; } else { - mlock_vma_pages_range(vma, start, end, &new_vma_flags); + ret = mlock_vma_pages_range(vma, start, end, &new_vma_flags); } out: *prev = vma; @@ -739,9 +746,18 @@ static int apply_mlockall_flags(int flags) error = mlock_fixup(&vmi, vma, &prev, vma->vm_start, vma->vm_end, newflags); - /* Ignore errors, but prev needs fixing up. */ - if (error) + if (error) { + /* + * If we failed due to a pending fatal signal, return + * now. If we locked the vma before signal arrived, it + * will be unlocked when we drop mmap_write_lock. + */ + if (fatal_signal_pending(current)) + return -EINTR; + + /* Ignore errors, but prev needs fixing up. */ prev = vma; + } cond_resched(); } out: diff --git a/mm/mprotect.c b/mm/mprotect.c index 110d47a36d4b..ae6ed882b600 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -768,7 +768,10 @@ mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb, * vm_flags and vm_page_prot are protected by the mmap_lock * held in write mode. */ - vma_start_write(vma); + error = vma_start_write_killable(vma); + if (error) + goto fail; + vma_flags_reset_once(vma, &new_vma_flags); if (vma_wants_manual_pte_write_upgrade(vma)) mm_cp_flags |= MM_CP_TRY_CHANGE_WRITABLE; diff --git a/mm/mremap.c b/mm/mremap.c index e9c8b1d05832..dec39ec314f9 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -1356,7 +1356,9 @@ static unsigned long move_vma(struct vma_remap_struct *vrm) return -ENOMEM; /* We don't want racing faults. */ - vma_start_write(vrm->vma); + err = vma_start_write_killable(vrm->vma); + if (err) + return err; /* Perform copy step. */ err = copy_vma_and_data(vrm, &new_vma); diff --git a/mm/vma.c b/mm/vma.c index ba78ab1f397a..7930a4270eb9 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -524,6 +524,17 @@ __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); } + /* + * Lock VMAs before cloning to avoid extra work if fatal signal + * is pending. + */ + err = vma_start_write_killable(vma); + if (err) + goto out_free_vma; + err = vma_start_write_killable(new); + if (err) + goto out_free_vma; + err = -ENOMEM; vma_iter_config(vmi, new->vm_start, new->vm_end); if (vma_iter_prealloc(vmi, new)) @@ -543,9 +554,6 @@ __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, if (new->vm_ops && new->vm_ops->open) new->vm_ops->open(new); - vma_start_write(vma); - vma_start_write(new); - init_vma_prep(&vp, vma); vp.insert = new; vma_prepare(&vp); @@ -900,12 +908,16 @@ static __must_check struct vm_area_struct *vma_merge_existing_range( } /* No matter what happens, we will be adjusting middle. */ - vma_start_write(middle); + err = vma_start_write_killable(middle); + if (err) + goto abort; if (merge_right) { vma_flags_t next_sticky; - vma_start_write(next); + err = vma_start_write_killable(next); + if (err) + goto abort; vmg->target = next; next_sticky = vma_flags_and_mask(&next->flags, VMA_STICKY_FLAGS); vma_flags_set_mask(&sticky_flags, next_sticky); @@ -914,7 +926,9 @@ static __must_check struct vm_area_struct *vma_merge_existing_range( if (merge_left) { vma_flags_t prev_sticky; - vma_start_write(prev); + err = vma_start_write_killable(prev); + if (err) + goto abort; vmg->target = prev; prev_sticky = vma_flags_and_mask(&prev->flags, VMA_STICKY_FLAGS); @@ -1170,10 +1184,12 @@ int vma_expand(struct vma_merge_struct *vmg) vma_flags_t sticky_flags = vma_flags_and_mask(&vmg->vma_flags, VMA_STICKY_FLAGS); vma_flags_t target_sticky; - int err = 0; + int err; mmap_assert_write_locked(vmg->mm); - vma_start_write(target); + err = vma_start_write_killable(target); + if (err) + return err; target_sticky = vma_flags_and_mask(&target->flags, VMA_STICKY_FLAGS); @@ -1201,6 +1217,13 @@ int vma_expand(struct vma_merge_struct *vmg) * we don't need to account for vmg->give_up_on_mm here. */ if (remove_next) { + /* + * Lock the VMA early to avoid extra work if fatal signal + * is pending. + */ + err = vma_start_write_killable(next); + if (err) + return err; err = dup_anon_vma(target, next, &anon_dup); if (err) return err; @@ -1214,7 +1237,6 @@ int vma_expand(struct vma_merge_struct *vmg) if (remove_next) { vma_flags_t next_sticky; - vma_start_write(next); vmg->__remove_next = true; next_sticky = vma_flags_and_mask(&next->flags, VMA_STICKY_FLAGS); @@ -1252,9 +1274,14 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma, unsigned long start, unsigned long end, pgoff_t pgoff) { struct vma_prepare vp; + int err; WARN_ON((vma->vm_start != start) && (vma->vm_end != end)); + err = vma_start_write_killable(vma); + if (err) + return err; + if (vma->vm_start < start) vma_iter_config(vmi, vma->vm_start, start); else @@ -1263,8 +1290,6 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma, if (vma_iter_prealloc(vmi, NULL)) return -ENOMEM; - vma_start_write(vma); - init_vma_prep(&vp, vma); vma_prepare(&vp); vma_adjust_trans_huge(vma, start, end, NULL); @@ -1453,7 +1478,9 @@ static int vms_gather_munmap_vmas(struct vma_munmap_struct *vms, if (error) goto end_split_failed; } - vma_start_write(next); + error = vma_start_write_killable(next); + if (error) + goto munmap_gather_failed; mas_set(mas_detach, vms->vma_count++); error = mas_store_gfp(mas_detach, next, GFP_KERNEL); if (error) @@ -1848,12 +1875,16 @@ static void vma_link_file(struct vm_area_struct *vma, bool hold_rmap_lock) static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma) { VMA_ITERATOR(vmi, mm, 0); + int err; + + err = vma_start_write_killable(vma); + if (err) + return err; vma_iter_config(&vmi, vma->vm_start, vma->vm_end); if (vma_iter_prealloc(&vmi, vma)) return -ENOMEM; - vma_start_write(vma); vma_iter_store_new(&vmi, vma); vma_link_file(vma, /* hold_rmap_lock= */false); mm->map_count++; @@ -2239,9 +2270,8 @@ int mm_take_all_locks(struct mm_struct *mm) * is reached. */ for_each_vma(vmi, vma) { - if (signal_pending(current)) + if (signal_pending(current) || vma_start_write_killable(vma)) goto out_unlock; - vma_start_write(vma); } vma_iter_init(&vmi, mm, 0); @@ -2540,8 +2570,8 @@ static int __mmap_new_vma(struct mmap_state *map, struct vm_area_struct **vmap, struct mmap_action *action) { struct vma_iterator *vmi = map->vmi; - int error = 0; struct vm_area_struct *vma; + int error; /* * Determine the object being mapped and call the appropriate @@ -2552,6 +2582,14 @@ static int __mmap_new_vma(struct mmap_state *map, struct vm_area_struct **vmap, if (!vma) return -ENOMEM; + /* + * Lock the VMA early to avoid extra work if fatal signal + * is pending. + */ + error = vma_start_write_killable(vma); + if (error) + goto free_vma; + vma_iter_config(vmi, map->addr, map->end); vma_set_range(vma, map->addr, map->end, map->pgoff); vma->flags = map->vma_flags; @@ -2582,8 +2620,6 @@ static int __mmap_new_vma(struct mmap_state *map, struct vm_area_struct **vmap, WARN_ON_ONCE(!arch_validate_flags(map->vm_flags)); #endif - /* Lock the VMA since it is modified after insertion into VMA tree */ - vma_start_write(vma); vma_iter_store_new(vmi, vma); map->mm->map_count++; vma_link_file(vma, action->hide_from_rmap_until_complete); @@ -2878,6 +2914,7 @@ int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma, unsigned long addr, unsigned long len, vma_flags_t vma_flags) { struct mm_struct *mm = current->mm; + int err; /* * Check against address space limits by the changed size @@ -2910,24 +2947,33 @@ int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma, if (vma_merge_new_range(&vmg)) goto out; - else if (vmg_nomem(&vmg)) + if (vmg_nomem(&vmg)) { + err = -ENOMEM; goto unacct_fail; + } } if (vma) vma_iter_next_range(vmi); /* create a vma struct for an anonymous mapping */ vma = vm_area_alloc(mm); - if (!vma) + if (!vma) { + err = -ENOMEM; goto unacct_fail; + } vma_set_anonymous(vma); vma_set_range(vma, addr, addr + len, addr >> PAGE_SHIFT); vma->flags = vma_flags; vma->vm_page_prot = vm_get_page_prot(vma_flags_to_legacy(vma_flags)); - vma_start_write(vma); - if (vma_iter_store_gfp(vmi, vma, GFP_KERNEL)) + if (vma_start_write_killable(vma)) { + err = -EINTR; + goto vma_lock_fail; + } + if (vma_iter_store_gfp(vmi, vma, GFP_KERNEL)) { + err = -ENOMEM; goto mas_store_fail; + } mm->map_count++; validate_mm(mm); @@ -2942,10 +2988,11 @@ int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma, return 0; mas_store_fail: +vma_lock_fail: vm_area_free(vma); unacct_fail: vm_unacct_memory(len >> PAGE_SHIFT); - return -ENOMEM; + return err; } /** @@ -3112,8 +3159,8 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address) struct mm_struct *mm = vma->vm_mm; struct vm_area_struct *next; unsigned long gap_addr; - int error = 0; VMA_ITERATOR(vmi, mm, vma->vm_start); + int error; if (!vma_test(vma, VMA_GROWSUP_BIT)) return -EFAULT; @@ -3149,12 +3196,14 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address) /* We must make sure the anon_vma is allocated. */ if (unlikely(anon_vma_prepare(vma))) { - vma_iter_free(&vmi); - return -ENOMEM; + error = -ENOMEM; + goto vma_prep_fail; } /* Lock the VMA before expanding to prevent concurrent page faults */ - vma_start_write(vma); + error = vma_start_write_killable(vma); + if (error) + goto vma_lock_fail; /* We update the anon VMA tree. */ anon_vma_lock_write(vma->anon_vma); @@ -3183,6 +3232,8 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address) } } anon_vma_unlock_write(vma->anon_vma); +vma_lock_fail: +vma_prep_fail: vma_iter_free(&vmi); validate_mm(mm); return error; @@ -3197,8 +3248,8 @@ int expand_downwards(struct vm_area_struct *vma, unsigned long address) { struct mm_struct *mm = vma->vm_mm; struct vm_area_struct *prev; - int error = 0; VMA_ITERATOR(vmi, mm, vma->vm_start); + int error; if (!vma_test(vma, VMA_GROWSDOWN_BIT)) return -EFAULT; @@ -3228,12 +3279,14 @@ int expand_downwards(struct vm_area_struct *vma, unsigned long address) /* We must make sure the anon_vma is allocated. */ if (unlikely(anon_vma_prepare(vma))) { - vma_iter_free(&vmi); - return -ENOMEM; + error = -ENOMEM; + goto vma_prep_fail; } /* Lock the VMA before expanding to prevent concurrent page faults */ - vma_start_write(vma); + error = vma_start_write_killable(vma); + if (error) + goto vma_lock_fail; /* We update the anon VMA tree. */ anon_vma_lock_write(vma->anon_vma); @@ -3263,6 +3316,8 @@ int expand_downwards(struct vm_area_struct *vma, unsigned long address) } } anon_vma_unlock_write(vma->anon_vma); +vma_lock_fail: +vma_prep_fail: vma_iter_free(&vmi); validate_mm(mm); return error; diff --git a/mm/vma_exec.c b/mm/vma_exec.c index 5cee8b7efa0f..8ddcc791d828 100644 --- a/mm/vma_exec.c +++ b/mm/vma_exec.c @@ -41,6 +41,7 @@ int relocate_vma_down(struct vm_area_struct *vma, unsigned long shift) struct vm_area_struct *next; struct mmu_gather tlb; PAGETABLE_MOVE(pmc, vma, vma, old_start, new_start, length); + int err; BUG_ON(new_start > new_end); @@ -56,8 +57,9 @@ int relocate_vma_down(struct vm_area_struct *vma, unsigned long shift) * cover the whole range: [new_start, old_end) */ vmg.target = vma; - if (vma_expand(&vmg)) - return -ENOMEM; + err = vma_expand(&vmg); + if (err) + return err; /* * move the page tables downwards, on failure we rely on -- 2.53.0.1018.g2bb0e51243-goog