Hi Gabriel, url: https://github.com/0day-ci/linux/commits/Gabriel-Krisman-Bertazi/File-system-wide-monitoring/20210630-031347 base: https://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git fsnotify config: x86_64-randconfig-m001-20210628 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> smatch warnings: fs/notify/fsnotify.c:505 __fsnotify() warn: variable dereferenced before check 'inode' (see line 494) vim +/inode +505 fs/notify/fsnotify.c dca640915c7b84 Amir Goldstein 2021-06-29 470 int __fsnotify(__u32 mask, const struct fsnotify_event_info *event_info) 90586523eb4b34 Eric Paris 2009-05-21 471 { dca640915c7b84 Amir Goldstein 2021-06-29 472 const struct path *path = fsnotify_event_info_path(event_info); dca640915c7b84 Amir Goldstein 2021-06-29 473 struct inode *inode = event_info->inode; 3427ce71554123 Miklos Szeredi 2017-10-30 474 struct fsnotify_iter_info iter_info = {}; 40a100d3adc1ad Amir Goldstein 2020-07-22 475 struct super_block *sb; 60f7ed8c7c4d06 Amir Goldstein 2018-09-01 476 struct mount *mnt = NULL; fecc4559780d52 Amir Goldstein 2020-12-02 477 struct inode *parent = NULL; 9385a84d7e1f65 Jan Kara 2016-11-10 478 int ret = 0; 71d734103edfa2 Mel Gorman 2020-07-08 479 __u32 test_mask, marks_mask; 90586523eb4b34 Eric Paris 2009-05-21 480 71d734103edfa2 Mel Gorman 2020-07-08 481 if (path) aa93bdc5500cc9 Amir Goldstein 2020-03-19 482 mnt = real_mount(path->mnt); 3a9fb89f4cd04c Eric Paris 2009-12-17 483 40a100d3adc1ad Amir Goldstein 2020-07-22 484 if (!inode) { 40a100d3adc1ad Amir Goldstein 2020-07-22 485 /* Dirent event - report on TYPE_INODE to dir */ dca640915c7b84 Amir Goldstein 2021-06-29 486 inode = event_info->dir; ^^^^^^^^^^^^^^^^^^^^^^^ Presumably this is non-NULL 40a100d3adc1ad Amir Goldstein 2020-07-22 487 } else if (mask & FS_EVENT_ON_CHILD) { 40a100d3adc1ad Amir Goldstein 2020-07-22 488 /* fecc4559780d52 Amir Goldstein 2020-12-02 489 * Event on child - report on TYPE_PARENT to dir if it is fecc4559780d52 Amir Goldstein 2020-12-02 490 * watching children and on TYPE_INODE to child. 40a100d3adc1ad Amir Goldstein 2020-07-22 491 */ dca640915c7b84 Amir Goldstein 2021-06-29 492 parent = event_info->dir; 40a100d3adc1ad Amir Goldstein 2020-07-22 493 } 40a100d3adc1ad Amir Goldstein 2020-07-22 @494 sb = inode->i_sb; ^^^^^^^^^^^^ Dereference 497b0c5a7c0688 Amir Goldstein 2020-07-16 495 7c49b8616460eb Dave Hansen 2015-09-04 496 /* 7c49b8616460eb Dave Hansen 2015-09-04 497 * Optimization: srcu_read_lock() has a memory barrier which can 7c49b8616460eb Dave Hansen 2015-09-04 498 * be expensive. It protects walking the *_fsnotify_marks lists. 7c49b8616460eb Dave Hansen 2015-09-04 499 * However, if we do not walk the lists, we do not have to do 7c49b8616460eb Dave Hansen 2015-09-04 500 * SRCU because we have no references to any objects and do not 7c49b8616460eb Dave Hansen 2015-09-04 501 * need SRCU to keep them "alive". 7c49b8616460eb Dave Hansen 2015-09-04 502 */ 9b93f33105f5f9 Amir Goldstein 2020-07-16 503 if (!sb->s_fsnotify_marks && 497b0c5a7c0688 Amir Goldstein 2020-07-16 504 (!mnt || !mnt->mnt_fsnotify_marks) && 9b93f33105f5f9 Amir Goldstein 2020-07-16 @505 (!inode || !inode->i_fsnotify_marks) && ^^^^^^ Unnecessary check for NULL fecc4559780d52 Amir Goldstein 2020-12-02 506 (!parent || !parent->i_fsnotify_marks)) 7c49b8616460eb Dave Hansen 2015-09-04 507 return 0; 71d734103edfa2 Mel Gorman 2020-07-08 508 9b93f33105f5f9 Amir Goldstein 2020-07-16 509 marks_mask = sb->s_fsnotify_mask; 71d734103edfa2 Mel Gorman 2020-07-08 510 if (mnt) 71d734103edfa2 Mel Gorman 2020-07-08 511 marks_mask |= mnt->mnt_fsnotify_mask; 9b93f33105f5f9 Amir Goldstein 2020-07-16 512 if (inode) ^^^^^^ 9b93f33105f5f9 Amir Goldstein 2020-07-16 513 marks_mask |= inode->i_fsnotify_mask; fecc4559780d52 Amir Goldstein 2020-12-02 514 if (parent) fecc4559780d52 Amir Goldstein 2020-12-02 515 marks_mask |= parent->i_fsnotify_mask; 497b0c5a7c0688 Amir Goldstein 2020-07-16 516 71d734103edfa2 Mel Gorman 2020-07-08 517 613a807fe7c793 Eric Paris 2010-07-28 518 /* 613a807fe7c793 Eric Paris 2010-07-28 519 * if this is a modify event we may need to clear the ignored masks 497b0c5a7c0688 Amir Goldstein 2020-07-16 520 * otherwise return if none of the marks care about this type of event. 613a807fe7c793 Eric Paris 2010-07-28 521 */ 71d734103edfa2 Mel Gorman 2020-07-08 522 test_mask = (mask & ALL_FSNOTIFY_EVENTS); 71d734103edfa2 Mel Gorman 2020-07-08 523 if (!(mask & FS_MODIFY) && !(test_mask & marks_mask)) 613a807fe7c793 Eric Paris 2010-07-28 524 return 0; 75c1be487a690d Eric Paris 2010-07-28 525 9385a84d7e1f65 Jan Kara 2016-11-10 526 iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu); 75c1be487a690d Eric Paris 2010-07-28 527 45a9fb3725d886 Amir Goldstein 2019-01-10 528 iter_info.marks[FSNOTIFY_OBJ_TYPE_SB] = 45a9fb3725d886 Amir Goldstein 2019-01-10 529 fsnotify_first_mark(&sb->s_fsnotify_marks); 9bdda4e9cf2dce Amir Goldstein 2018-09-01 530 if (mnt) { 47d9c7cc457adc Amir Goldstein 2018-04-20 531 iter_info.marks[FSNOTIFY_OBJ_TYPE_VFSMOUNT] = 3427ce71554123 Miklos Szeredi 2017-10-30 532 fsnotify_first_mark(&mnt->mnt_fsnotify_marks); 7131485a93679f Eric Paris 2009-12-17 533 } 9b93f33105f5f9 Amir Goldstein 2020-07-16 534 if (inode) { ^^^^^ Lots of checking... Maybe this is really NULL? 9b93f33105f5f9 Amir Goldstein 2020-07-16 535 iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] = 9b93f33105f5f9 Amir Goldstein 2020-07-16 536 fsnotify_first_mark(&inode->i_fsnotify_marks); 9b93f33105f5f9 Amir Goldstein 2020-07-16 537 } fecc4559780d52 Amir Goldstein 2020-12-02 538 if (parent) { fecc4559780d52 Amir Goldstein 2020-12-02 539 iter_info.marks[FSNOTIFY_OBJ_TYPE_PARENT] = fecc4559780d52 Amir Goldstein 2020-12-02 540 fsnotify_first_mark(&parent->i_fsnotify_marks); 497b0c5a7c0688 Amir Goldstein 2020-07-16 541 } 75c1be487a690d Eric Paris 2010-07-28 542 8edc6e1688fc8f Jan Kara 2014-11-13 543 /* 60f7ed8c7c4d06 Amir Goldstein 2018-09-01 544 * We need to merge inode/vfsmount/sb mark lists so that e.g. inode mark 60f7ed8c7c4d06 Amir Goldstein 2018-09-01 545 * ignore masks are properly reflected for mount/sb mark notifications. 8edc6e1688fc8f Jan Kara 2014-11-13 546 * That's why this traversal is so complicated... 8edc6e1688fc8f Jan Kara 2014-11-13 547 */ d9a6f30bb89309 Amir Goldstein 2018-04-20 548 while (fsnotify_iter_select_report_types(&iter_info)) { dca640915c7b84 Amir Goldstein 2021-06-29 549 ret = send_to_group(mask, event_info, &iter_info); 613a807fe7c793 Eric Paris 2010-07-28 550 ff8bcbd03da881 Eric Paris 2010-10-28 551 if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS)) ff8bcbd03da881 Eric Paris 2010-10-28 552 goto out; ff8bcbd03da881 Eric Paris 2010-10-28 553 d9a6f30bb89309 Amir Goldstein 2018-04-20 554 fsnotify_iter_next(&iter_info); 90586523eb4b34 Eric Paris 2009-05-21 555 } ff8bcbd03da881 Eric Paris 2010-10-28 556 ret = 0; ff8bcbd03da881 Eric Paris 2010-10-28 557 out: 9385a84d7e1f65 Jan Kara 2016-11-10 558 srcu_read_unlock(&fsnotify_mark_srcu, iter_info.srcu_idx); c4ec54b40d33f8 Eric Paris 2009-12-17 559 98b5c10d320adf Jean-Christophe Dubois 2010-03-23 560 return ret; 90586523eb4b34 Eric Paris 2009-05-21 561 } --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
