Re: [PATCH 2/3] mm/mmu_notifier: use structure for invalidate_range_start/end calls

From: kbuild test robot
Date: Thu Dec 06 2018 - 15:36:49 EST


Hi Jérôme,

I love your patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.20-rc5]
[cannot apply to next-20181206]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url: https://github.com/0day-ci/linux/commits/jglisse-redhat-com/mmu-notifier-contextual-informations/20181207-031930
config: i386-randconfig-x007-201848 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
# save the attached .config to linux build tree
make ARCH=i386

All errors (new ones prefixed by >>):

kernel/events/uprobes.c: In function '__replace_page':
>> kernel/events/uprobes.c:174:28: error: storage size of 'range' isn't known
struct mmu_notifier_range range;
^~~~~
kernel/events/uprobes.c:174:28: warning: unused variable 'range' [-Wunused-variable]

vim +174 kernel/events/uprobes.c

152
153 /**
154 * __replace_page - replace page in vma by new page.
155 * based on replace_page in mm/ksm.c
156 *
157 * @vma: vma that holds the pte pointing to page
158 * @addr: address the old @page is mapped at
159 * @page: the cowed page we are replacing by kpage
160 * @kpage: the modified page we replace page by
161 *
162 * Returns 0 on success, -EFAULT on failure.
163 */
164 static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
165 struct page *old_page, struct page *new_page)
166 {
167 struct mm_struct *mm = vma->vm_mm;
168 struct page_vma_mapped_walk pvmw = {
169 .page = old_page,
170 .vma = vma,
171 .address = addr,
172 };
173 int err;
> 174 struct mmu_notifier_range range;
175 struct mem_cgroup *memcg;
176
177 range.start = addr;
178 range.end = addr + PAGE_SIZE;
179 range.mm = mm;
180
181 VM_BUG_ON_PAGE(PageTransHuge(old_page), old_page);
182
183 err = mem_cgroup_try_charge(new_page, vma->vm_mm, GFP_KERNEL, &memcg,
184 false);
185 if (err)
186 return err;
187
188 /* For try_to_free_swap() and munlock_vma_page() below */
189 lock_page(old_page);
190
191 mmu_notifier_invalidate_range_start(&range);
192 err = -EAGAIN;
193 if (!page_vma_mapped_walk(&pvmw)) {
194 mem_cgroup_cancel_charge(new_page, memcg, false);
195 goto unlock;
196 }
197 VM_BUG_ON_PAGE(addr != pvmw.address, old_page);
198
199 get_page(new_page);
200 page_add_new_anon_rmap(new_page, vma, addr, false);
201 mem_cgroup_commit_charge(new_page, memcg, false, false);
202 lru_cache_add_active_or_unevictable(new_page, vma);
203
204 if (!PageAnon(old_page)) {
205 dec_mm_counter(mm, mm_counter_file(old_page));
206 inc_mm_counter(mm, MM_ANONPAGES);
207 }
208
209 flush_cache_page(vma, addr, pte_pfn(*pvmw.pte));
210 ptep_clear_flush_notify(vma, addr, pvmw.pte);
211 set_pte_at_notify(mm, addr, pvmw.pte,
212 mk_pte(new_page, vma->vm_page_prot));
213
214 page_remove_rmap(old_page, false);
215 if (!page_mapped(old_page))
216 try_to_free_swap(old_page);
217 page_vma_mapped_walk_done(&pvmw);
218
219 if (vma->vm_flags & VM_LOCKED)
220 munlock_vma_page(old_page);
221 put_page(old_page);
222
223 err = 0;
224 unlock:
225 mmu_notifier_invalidate_range_end(&range);
226 unlock_page(old_page);
227 return err;
228 }
229

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