From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============4059492714289021565==" MIME-Version: 1.0 From: kernel test robot Subject: block/bfq-cgroup.c:670:6: warning: Use of memory after it is freed [clang-analyzer-unix.Malloc] Date: Sun, 03 Jul 2022 10:35:02 +0800 Message-ID: <202207031050.E4jHtLZ9-lkp@intel.com> List-Id: To: kbuild@lists.01.org --===============4059492714289021565== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable :::::: = :::::: Manual check reason: "low confidence static check warning: block/bfq= -cgroup.c:670:6: warning: Use of memory after it is freed [clang-analyzer-u= nix.Malloc]" :::::: = CC: llvm(a)lists.linux.dev CC: kbuild-all(a)lists.01.org BCC: lkp(a)intel.com CC: linux-kernel(a)vger.kernel.org TO: Paolo Valente CC: Jens Axboe tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git = master head: 69cb6c6556ad89620547318439d6be8bb1629a5a commit: d29bd41428cfff9b582c248db14a47e2be8457a8 block, bfq: reset last_bfq= q_created on group change date: 9 months ago :::::: branch date: 8 hours ago :::::: commit date: 9 months ago config: arm-randconfig-c002-20220625 (https://download.01.org/0day-ci/archi= ve/20220703/202207031050.E4jHtLZ9-lkp(a)intel.com/config) compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 42a7dd= b428c999229491b0effbb1a4059149fba8) reproduce (this is a W=3D1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/= make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install arm cross compiling tool for clang build # apt-get install binutils-arm-linux-gnueabi # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.gi= t/commit/?id=3Dd29bd41428cfff9b582c248db14a47e2be8457a8 git remote add linus https://git.kernel.org/pub/scm/linux/kernel/gi= t/torvalds/linux.git git fetch --no-tags linus master git checkout d29bd41428cfff9b582c248db14a47e2be8457a8 # save the config file COMPILER_INSTALL_PATH=3D$HOME/0day COMPILER=3Dclang make.cross ARCH= =3Darm clang-analyzer = If you fix the issue, kindly add following tag where applicable Reported-by: kernel test robot clang-analyzer warnings: (new ones prefixed by >>) ^ include/linux/list.h:838:2: note: Left side of '||' is false WRITE_ONCE(*pprev, next); ^ include/asm-generic/rwonce.h:60:2: note: expanded from macro 'WRITE_ONCE' compiletime_assert_rwonce_type(x); \ ^ include/asm-generic/rwonce.h:36:21: note: expanded from macro 'compileti= me_assert_rwonce_type' compiletime_assert(__native_word(t) || sizeof(t) =3D=3D sizeof(l= ong long), \ ^ include/linux/compiler_types.h:290:3: note: expanded from macro '__nativ= e_word' (sizeof(t) =3D=3D sizeof(char) || sizeof(t) =3D=3D sizeof(short)= || \ ^ include/linux/list.h:838:2: note: Left side of '||' is true WRITE_ONCE(*pprev, next); ^ include/asm-generic/rwonce.h:60:2: note: expanded from macro 'WRITE_ONCE' compiletime_assert_rwonce_type(x); \ ^ include/asm-generic/rwonce.h:36:21: note: expanded from macro 'compileti= me_assert_rwonce_type' compiletime_assert(__native_word(t) || sizeof(t) =3D=3D sizeof(l= ong long), \ ^ include/linux/compiler_types.h:291:28: note: expanded from macro '__nati= ve_word' sizeof(t) =3D=3D sizeof(int) || sizeof(t) =3D=3D sizeof(long)) ^ include/linux/list.h:838:2: note: Taking false branch WRITE_ONCE(*pprev, next); ^ include/asm-generic/rwonce.h:60:2: note: expanded from macro 'WRITE_ONCE' compiletime_assert_rwonce_type(x); \ ^ include/asm-generic/rwonce.h:36:2: note: expanded from macro 'compiletim= e_assert_rwonce_type' compiletime_assert(__native_word(t) || sizeof(t) =3D=3D sizeof(l= ong long), \ ^ include/linux/compiler_types.h:322:2: note: expanded from macro 'compile= time_assert' _compiletime_assert(condition, msg, __compiletime_assert_, __COU= NTER__) ^ include/linux/compiler_types.h:310:2: note: expanded from macro '_compil= etime_assert' __compiletime_assert(condition, msg, prefix, suffix) ^ include/linux/compiler_types.h:302:3: note: expanded from macro '__compi= letime_assert' if (!(condition)) \ ^ include/linux/list.h:838:2: note: Loop condition is false. Exiting loop WRITE_ONCE(*pprev, next); ^ include/asm-generic/rwonce.h:60:2: note: expanded from macro 'WRITE_ONCE' compiletime_assert_rwonce_type(x); \ ^ include/asm-generic/rwonce.h:36:2: note: expanded from macro 'compiletim= e_assert_rwonce_type' compiletime_assert(__native_word(t) || sizeof(t) =3D=3D sizeof(l= ong long), \ ^ include/linux/compiler_types.h:322:2: note: expanded from macro 'compile= time_assert' _compiletime_assert(condition, msg, __compiletime_assert_, __COU= NTER__) ^ include/linux/compiler_types.h:310:2: note: expanded from macro '_compil= etime_assert' __compiletime_assert(condition, msg, prefix, suffix) ^ include/linux/compiler_types.h:300:2: note: expanded from macro '__compi= letime_assert' do { \ ^ include/linux/list.h:838:2: note: Dereference of null pointer WRITE_ONCE(*pprev, next); ^ include/asm-generic/rwonce.h:61:2: note: expanded from macro 'WRITE_ONCE' __WRITE_ONCE(x, val); \ ^~~~~~~~~~~~~~~~~~~~ include/asm-generic/rwonce.h:55:30: note: expanded from macro '__WRITE_O= NCE' *(volatile typeof(x) *)&(x) =3D (val); = \ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~ Suppressed 7 warnings (7 in non-user code). Use -header-filter=3D.* to display errors from all non-system headers. U= se -system-headers to display errors from system headers as well. 9 warnings generated. block/bfq-wf2q.c:263:7: warning: Access to field 'my_sched_data' results= in a dereference of a null pointer (loaded from variable 'entity') [clang-= analyzer-core.NullDereference] if (!entity->my_sched_data) ^ block/bfq-wf2q.c:1508:2: note: 'entity' initialized to a null pointer va= lue struct bfq_entity *entity =3D NULL; ^~~~~~~~~~~~~~~~~~~~~~~~~ block/bfq-wf2q.c:1512:6: note: Assuming the condition is false if (bfq_tot_busy_queues(bfqd) =3D=3D 0) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ block/bfq-wf2q.c:1512:2: note: Taking false branch if (bfq_tot_busy_queues(bfqd) =3D=3D 0) ^ block/bfq-wf2q.c:1521:2: note: Loop condition is false. Execution contin= ues on line 1582 for (; sd ; sd =3D entity->my_sched_data) { ^ block/bfq-wf2q.c:1582:28: note: Passing null pointer value via 1st param= eter 'entity' bfqq =3D bfq_entity_to_bfqq(entity); ^~~~~~ block/bfq-wf2q.c:1582:9: note: Calling 'bfq_entity_to_bfqq' bfqq =3D bfq_entity_to_bfqq(entity); ^~~~~~~~~~~~~~~~~~~~~~~~~~ block/bfq-wf2q.c:263:7: note: Access to field 'my_sched_data' results in= a dereference of a null pointer (loaded from variable 'entity') if (!entity->my_sched_data) ^~~~~~ Suppressed 8 warnings (8 in non-user code). Use -header-filter=3D.* to display errors from all non-system headers. U= se -system-headers to display errors from system headers as well. 9 warnings generated. >> block/bfq-cgroup.c:670:6: warning: Use of memory after it is freed [clan= g-analyzer-unix.Malloc] entity->parent->last_bfqq_created =3D=3D bfqq) ^ block/bfq-cgroup.c:892:2: note: Loop condition is false. Exiting loop spin_lock_irqsave(&bfqd->lock, flags); ^ include/linux/spinlock.h:393:2: note: expanded from macro 'spin_lock_irq= save' raw_spin_lock_irqsave(spinlock_check(lock), flags); \ ^ include/linux/spinlock.h:254:2: note: expanded from macro 'raw_spin_lock= _irqsave' do { \ ^ block/bfq-cgroup.c:892:2: note: Loop condition is false. Exiting loop spin_lock_irqsave(&bfqd->lock, flags); ^ include/linux/spinlock.h:391:43: note: expanded from macro 'spin_lock_ir= qsave' #define spin_lock_irqsave(lock, flags) \ ^ block/bfq-cgroup.c:894:6: note: Assuming 'entity' is non-null if (!entity) /* root group */ ^~~~~~~ block/bfq-cgroup.c:894:2: note: Taking false branch if (!entity) /* root group */ ^ block/bfq-cgroup.c:901:2: note: Loop condition is true. Entering loop b= ody for (i =3D 0; i < BFQ_IOPRIO_CLASSES; i++) { ^ block/bfq-cgroup.c:916:3: note: Calling 'bfq_reparent_active_queues' bfq_reparent_active_queues(bfqd, bfqg, st, i); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ block/bfq-cgroup.c:866:2: note: Loop condition is true. Entering loop b= ody while ((entity =3D bfq_entity_of(rb_first(active)))) ^ block/bfq-cgroup.c:867:3: note: Calling 'bfq_reparent_leaf_entity' bfq_reparent_leaf_entity(bfqd, entity, ioprio_class); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ block/bfq-cgroup.c:836:2: note: Loop condition is false. Execution conti= nues on line 848 while (child_entity->my_sched_data) { /* leaf not reached yet */ ^ block/bfq-cgroup.c:849:2: note: Calling 'bfq_bfqq_move' bfq_bfqq_move(bfqd, bfqq, bfqd->root_group); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ block/bfq-cgroup.c:659:6: note: Assuming 'bfqq' is not equal to field 'i= n_service_queue' if (bfqq =3D=3D bfqd->in_service_queue) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ block/bfq-cgroup.c:659:2: note: Taking false branch if (bfqq =3D=3D bfqd->in_service_queue) ^ block/bfq-cgroup.c:663:6: note: Assuming the condition is true if (bfq_bfqq_busy(bfqq)) ^~~~~~~~~~~~~~~~~~~ block/bfq-cgroup.c:663:2: note: Taking true branch if (bfq_bfqq_busy(bfqq)) ^ block/bfq-cgroup.c:667:20: note: Calling 'bfqq_group' bfqg_and_blkg_put(bfqq_group(bfqq)); ^~~~~~~~~~~~~~~~ block/bfq-cgroup.c:312:9: note: Assuming 'group_entity' is non-null return group_entity ? container_of(group_entity, struct bfq_grou= p, ^~~~~~~~~~~~ block/bfq-cgroup.c:312:9: note: '?' condition is true block/bfq-cgroup.c:312:24: note: Left side of '&&' is false return group_entity ? container_of(group_entity, struct bfq_grou= p, ^ include/linux/kernel.h:495:61: note: expanded from macro 'container_of' BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \ ^ block/bfq-cgroup.c:312:24: note: Taking false branch return group_entity ? container_of(group_entity, struct bfq_grou= p, ^ include/linux/kernel.h:495:2: note: expanded from macro 'container_of' BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \ ^ include/linux/build_bug.h:39:37: note: expanded from macro 'BUILD_BUG_ON= _MSG' #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) ^ include/linux/compiler_types.h:322:2: note: expanded from macro 'compile= time_assert' _compiletime_assert(condition, msg, __compiletime_assert_, __COU= NTER__) ^ include/linux/compiler_types.h:310:2: note: expanded from macro '_compil= etime_assert' __compiletime_assert(condition, msg, prefix, suffix) ^ include/linux/compiler_types.h:302:3: note: expanded from macro '__compi= letime_assert' if (!(condition)) \ ^ block/bfq-cgroup.c:312:24: note: Loop condition is false. Exiting loop return group_entity ? container_of(group_entity, struct bfq_grou= p, ^ include/linux/kernel.h:495:2: note: expanded from macro 'container_of' BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \ ^ include/linux/build_bug.h:39:37: note: expanded from macro 'BUILD_BUG_ON= _MSG' #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) ^ include/linux/compiler_types.h:322:2: note: expanded from macro 'compile= time_assert' _compiletime_assert(condition, msg, __compiletime_assert_, __COU= NTER__) ^ include/linux/compiler_types.h:310:2: note: expanded from macro '_compil= etime_assert' __compiletime_assert(condition, msg, prefix, suffix) ^ include/linux/compiler_types.h:300:2: note: expanded from macro '__compi= letime_assert' vim +670 block/bfq-cgroup.c ea25da48086d3b Paolo Valente 2017-04-19 627 = ea25da48086d3b Paolo Valente 2017-04-19 628 /** ea25da48086d3b Paolo Valente 2017-04-19 629 * bfq_bfqq_move - migrate @b= fqq to @bfqg. ea25da48086d3b Paolo Valente 2017-04-19 630 * @bfqd: queue descriptor. ea25da48086d3b Paolo Valente 2017-04-19 631 * @bfqq: the queue to move. ea25da48086d3b Paolo Valente 2017-04-19 632 * @bfqg: the group to move t= o. ea25da48086d3b Paolo Valente 2017-04-19 633 * ea25da48086d3b Paolo Valente 2017-04-19 634 * Move @bfqq to @bfqg, deact= ivating it from its old group and reactivating ea25da48086d3b Paolo Valente 2017-04-19 635 * it on the new one. Avoid = putting the entity on the old group idle tree. ea25da48086d3b Paolo Valente 2017-04-19 636 * 8f9bebc33dd718 Paolo Valente 2017-06-05 637 * Must be called under the s= cheduler lock, to make sure that the blkg 8f9bebc33dd718 Paolo Valente 2017-06-05 638 * owning @bfqg does not disa= ppear (see comments in 8f9bebc33dd718 Paolo Valente 2017-06-05 639 * bfq_bic_update_cgroup on g= uaranteeing the consistency of blkg 8f9bebc33dd718 Paolo Valente 2017-06-05 640 * objects). ea25da48086d3b Paolo Valente 2017-04-19 641 */ ea25da48086d3b Paolo Valente 2017-04-19 642 void bfq_bfqq_move(struct bfq= _data *bfqd, struct bfq_queue *bfqq, ea25da48086d3b Paolo Valente 2017-04-19 643 struct bfq_group *bfqg) ea25da48086d3b Paolo Valente 2017-04-19 644 { ea25da48086d3b Paolo Valente 2017-04-19 645 struct bfq_entity *entity = =3D &bfqq->entity; ea25da48086d3b Paolo Valente 2017-04-19 646 = fd1bb3ae54a9a2 Paolo Valente 2020-03-21 647 /* fd1bb3ae54a9a2 Paolo Valente 2020-03-21 648 * Get extra reference to pr= event bfqq from being freed in fd1bb3ae54a9a2 Paolo Valente 2020-03-21 649 * next possible expire or d= eactivate. fd1bb3ae54a9a2 Paolo Valente 2020-03-21 650 */ fd1bb3ae54a9a2 Paolo Valente 2020-03-21 651 bfqq->ref++; fd1bb3ae54a9a2 Paolo Valente 2020-03-21 652 = ea25da48086d3b Paolo Valente 2017-04-19 653 /* If bfqq is empty, then bf= q_bfqq_expire also invokes ea25da48086d3b Paolo Valente 2017-04-19 654 * bfq_del_bfqq_busy, thereb= y removing bfqq and its entity ea25da48086d3b Paolo Valente 2017-04-19 655 * from data structures rela= ted to current group. Otherwise we ea25da48086d3b Paolo Valente 2017-04-19 656 * need to remove bfqq expli= citly with bfq_deactivate_bfqq, as ea25da48086d3b Paolo Valente 2017-04-19 657 * we do below. ea25da48086d3b Paolo Valente 2017-04-19 658 */ ea25da48086d3b Paolo Valente 2017-04-19 659 if (bfqq =3D=3D bfqd->in_ser= vice_queue) ea25da48086d3b Paolo Valente 2017-04-19 660 bfq_bfqq_expire(bfqd, bfqd-= >in_service_queue, ea25da48086d3b Paolo Valente 2017-04-19 661 false, BFQQE_PREEMPTED); ea25da48086d3b Paolo Valente 2017-04-19 662 = ea25da48086d3b Paolo Valente 2017-04-19 663 if (bfq_bfqq_busy(bfqq)) ea25da48086d3b Paolo Valente 2017-04-19 664 bfq_deactivate_bfqq(bfqd, b= fqq, false, false); 33a16a9804688b Paolo Valente 2020-02-03 665 else if (entity->on_st_or_in= _serv) ea25da48086d3b Paolo Valente 2017-04-19 666 bfq_put_idle_entity(bfq_ent= ity_service_tree(entity), entity); 8f9bebc33dd718 Paolo Valente 2017-06-05 667 bfqg_and_blkg_put(bfqq_group= (bfqq)); ea25da48086d3b Paolo Valente 2017-04-19 668 = d29bd41428cfff Paolo Valente 2021-10-15 669 if (entity->parent && d29bd41428cfff Paolo Valente 2021-10-15 @670 entity->parent->last_bfq= q_created =3D=3D bfqq) d29bd41428cfff Paolo Valente 2021-10-15 671 entity->parent->last_bfqq_c= reated =3D NULL; d29bd41428cfff Paolo Valente 2021-10-15 672 else if (bfqd->last_bfqq_cre= ated =3D=3D bfqq) d29bd41428cfff Paolo Valente 2021-10-15 673 bfqd->last_bfqq_created =3D= NULL; d29bd41428cfff Paolo Valente 2021-10-15 674 = ea25da48086d3b Paolo Valente 2017-04-19 675 entity->parent =3D bfqg->my_= entity; ea25da48086d3b Paolo Valente 2017-04-19 676 entity->sched_data =3D &bfqg= ->sched_data; 8f9bebc33dd718 Paolo Valente 2017-06-05 677 /* pin down bfqg and its ass= ociated blkg */ 8f9bebc33dd718 Paolo Valente 2017-06-05 678 bfqg_and_blkg_get(bfqg); ea25da48086d3b Paolo Valente 2017-04-19 679 = ea25da48086d3b Paolo Valente 2017-04-19 680 if (bfq_bfqq_busy(bfqq)) { 8cacc5ab3eacf5 Paolo Valente 2019-03-12 681 if (unlikely(!bfqd->nonrot_= with_queueing)) ea25da48086d3b Paolo Valente 2017-04-19 682 bfq_pos_tree_add_move(bfqd= , bfqq); ea25da48086d3b Paolo Valente 2017-04-19 683 bfq_activate_bfqq(bfqd, bfq= q); ea25da48086d3b Paolo Valente 2017-04-19 684 } ea25da48086d3b Paolo Valente 2017-04-19 685 = ea25da48086d3b Paolo Valente 2017-04-19 686 if (!bfqd->in_service_queue = && !bfqd->rq_in_driver) ea25da48086d3b Paolo Valente 2017-04-19 687 bfq_schedule_dispatch(bfqd); fd1bb3ae54a9a2 Paolo Valente 2020-03-21 688 /* release extra ref taken a= bove, bfqq may happen to be freed now */ ecedd3d7e19911 Paolo Valente 2020-02-03 689 bfq_put_queue(bfqq); ea25da48086d3b Paolo Valente 2017-04-19 690 } ea25da48086d3b Paolo Valente 2017-04-19 691 = -- = 0-DAY CI Kernel Test Service https://01.org/lkp --===============4059492714289021565==--