Hi Michal, [auto build test ERROR on mmotm/master] [also build test ERROR on v4.13-rc2 next-20170724] [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/Michal-Hocko/mm-oom-allow-oom-reaper-to-race-with-exit_mmap/20170724-233159 base: git://git.cmpxchg.org/linux-mmotm.git master config: x86_64-randconfig-x016-201730 (attached as .config) compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901 reproduce: # save the attached .config to linux build tree make ARCH=x86_64 All error/warnings (new ones prefixed by >>): mm/oom_kill.c: In function '__oom_reap_task_mm': >> mm/oom_kill.c:523:9: error: 'ret' undeclared (first use in this function) return ret; ^~~ mm/oom_kill.c:523:9: note: each undeclared identifier is reported only once for each function it appears in >> mm/oom_kill.c:524:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ vim +/ret +523 mm/oom_kill.c 03049269d Michal Hocko 2016-03-25 468 7ebffa455 Tetsuo Handa 2016-10-07 469 static bool __oom_reap_task_mm(struct task_struct *tsk, struct mm_struct *mm) aac453635 Michal Hocko 2016-03-25 470 { aac453635 Michal Hocko 2016-03-25 471 struct mmu_gather tlb; aac453635 Michal Hocko 2016-03-25 472 struct vm_area_struct *vma; e2fe14564 Michal Hocko 2016-05-27 473 aac453635 Michal Hocko 2016-03-25 474 if (!down_read_trylock(&mm->mmap_sem)) { fa60da35c Andrew Morton 2017-07-14 475 trace_skip_task_reaping(tsk->pid); ed7a155c6 Michal Hocko 2017-07-24 476 return false; e5e3f4c4f Michal Hocko 2016-07-26 477 } e5e3f4c4f Michal Hocko 2016-07-26 478 ed7a155c6 Michal Hocko 2017-07-24 479 /* There is nothing to reap so bail out without signs in the log */ ed7a155c6 Michal Hocko 2017-07-24 480 if (!mm->mmap) ed7a155c6 Michal Hocko 2017-07-24 481 goto unlock; aac453635 Michal Hocko 2016-03-25 482 fa60da35c Andrew Morton 2017-07-14 483 trace_start_task_reaping(tsk->pid); fa60da35c Andrew Morton 2017-07-14 484 3f70dc38c Michal Hocko 2016-10-07 485 /* 3f70dc38c Michal Hocko 2016-10-07 486 * Tell all users of get_user/copy_from_user etc... that the content 3f70dc38c Michal Hocko 2016-10-07 487 * is no longer stable. No barriers really needed because unmapping 3f70dc38c Michal Hocko 2016-10-07 488 * should imply barriers already and the reader would hit a page fault 3f70dc38c Michal Hocko 2016-10-07 489 * if it stumbled over a reaped memory. 3f70dc38c Michal Hocko 2016-10-07 490 */ 3f70dc38c Michal Hocko 2016-10-07 491 set_bit(MMF_UNSTABLE, &mm->flags); 3f70dc38c Michal Hocko 2016-10-07 492 aac453635 Michal Hocko 2016-03-25 493 tlb_gather_mmu(&tlb, mm, 0, -1); aac453635 Michal Hocko 2016-03-25 494 for (vma = mm->mmap ; vma; vma = vma->vm_next) { 235190738 Kirill A. Shutemov 2017-02-22 495 if (!can_madv_dontneed_vma(vma)) aac453635 Michal Hocko 2016-03-25 496 continue; aac453635 Michal Hocko 2016-03-25 497 aac453635 Michal Hocko 2016-03-25 498 /* aac453635 Michal Hocko 2016-03-25 499 * Only anonymous pages have a good chance to be dropped aac453635 Michal Hocko 2016-03-25 500 * without additional steps which we cannot afford as we aac453635 Michal Hocko 2016-03-25 501 * are OOM already. aac453635 Michal Hocko 2016-03-25 502 * aac453635 Michal Hocko 2016-03-25 503 * We do not even care about fs backed pages because all aac453635 Michal Hocko 2016-03-25 504 * which are reclaimable have already been reclaimed and aac453635 Michal Hocko 2016-03-25 505 * we do not want to block exit_mmap by keeping mm ref aac453635 Michal Hocko 2016-03-25 506 * count elevated without a good reason. aac453635 Michal Hocko 2016-03-25 507 */ aac453635 Michal Hocko 2016-03-25 508 if (vma_is_anonymous(vma) || !(vma->vm_flags & VM_SHARED)) aac453635 Michal Hocko 2016-03-25 509 unmap_page_range(&tlb, vma, vma->vm_start, vma->vm_end, 3e8715fdc Kirill A. Shutemov 2017-02-22 510 NULL); aac453635 Michal Hocko 2016-03-25 511 } aac453635 Michal Hocko 2016-03-25 512 tlb_finish_mmu(&tlb, 0, -1); bc448e897 Michal Hocko 2016-03-25 513 pr_info("oom_reaper: reaped process %d (%s), now anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB\n", bc448e897 Michal Hocko 2016-03-25 514 task_pid_nr(tsk), tsk->comm, bc448e897 Michal Hocko 2016-03-25 515 K(get_mm_counter(mm, MM_ANONPAGES)), bc448e897 Michal Hocko 2016-03-25 516 K(get_mm_counter(mm, MM_FILEPAGES)), bc448e897 Michal Hocko 2016-03-25 517 K(get_mm_counter(mm, MM_SHMEMPAGES))); 36324a990 Michal Hocko 2016-03-25 518 fa60da35c Andrew Morton 2017-07-14 519 trace_finish_task_reaping(tsk->pid); ed7a155c6 Michal Hocko 2017-07-24 520 unlock: ed7a155c6 Michal Hocko 2017-07-24 521 up_read(&mm->mmap_sem); ed7a155c6 Michal Hocko 2017-07-24 522 aac453635 Michal Hocko 2016-03-25 @523 return ret; aac453635 Michal Hocko 2016-03-25 @524 } aac453635 Michal Hocko 2016-03-25 525 :::::: The code at line 523 was first introduced by commit :::::: aac453635549699c13a84ea1456d5b0e574ef855 mm, oom: introduce oom reaper :::::: TO: Michal Hocko <mhocko@xxxxxxxx> :::::: CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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