On Sun, Jul 26, 2020 at 11:28:55AM +0800, kernel test robot wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev.2020.07.14a > head: aace6daf32cce6b644083754c7be6260aae439db > commit: 93d62a873f87bf69209a5c29d62b9497888de6d6 [64/73] kvm: mmu: page_track: Fix RCU list API usage > config: i386-randconfig-a006-20200726 (attached as .config) > compiler: gcc-9 (Debian 9.3.0-14) 9.3.0 > reproduce (this is a W=1 build): > git checkout 93d62a873f87bf69209a5c29d62b9497888de6d6 > # save the attached .config to linux build tree > make W=1 ARCH=i386 > > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot Good catch, but this commit has been superseded by 74e71f01ff46 ("kvm: mmu: page_track: Fix RCU list API usage"). As always, thank you for your testing efforts. Thanx, Paul > Note: the rcu/dev.2020.07.14a HEAD aace6daf32cce6b644083754c7be6260aae439db builds fine. > It only hurts bisectibility. > > All errors (new ones prefixed by >>): > > In file included from include/linux/pid.h:5, > from include/linux/sched.h:14, > from include/linux/kvm_host.h:12, > from arch/x86/kvm/mmu/page_track.c:14: > arch/x86/kvm/mmu/page_track.c: In function 'kvm_page_track_write': > >> include/linux/rculist.h:727:30: error: left-hand operand of comma expression has no effect [-Werror=unused-value] > 727 | for (__list_check_srcu(cond), \ > | ^ > arch/x86/kvm/mmu/page_track.c:232:2: note: in expansion of macro 'hlist_for_each_entry_srcu' > 232 | hlist_for_each_entry_srcu(n, &head->track_notifier_list, node, > | ^~~~~~~~~~~~~~~~~~~~~~~~~ > arch/x86/kvm/mmu/page_track.c: In function 'kvm_page_track_flush_slot': > >> include/linux/rculist.h:727:30: error: left-hand operand of comma expression has no effect [-Werror=unused-value] > 727 | for (__list_check_srcu(cond), \ > | ^ > arch/x86/kvm/mmu/page_track.c:258:2: note: in expansion of macro 'hlist_for_each_entry_srcu' > 258 | hlist_for_each_entry_srcu(n, &head->track_notifier_list, node, > | ^~~~~~~~~~~~~~~~~~~~~~~~~ > cc1: all warnings being treated as errors > > vim +727 include/linux/rculist.h > > 82524746c27fa41 Franck Bui-Huu 2008-05-12 688 > 1cc523271ef0b63 stephen hemminger 2010-02-22 689 #define __hlist_for_each_rcu(pos, head) \ > 67bdbffd696f29a Arnd Bergmann 2010-02-25 690 for (pos = rcu_dereference(hlist_first_rcu(head)); \ > 75d65a425c0163d Linus Torvalds 2011-05-19 691 pos; \ > 67bdbffd696f29a Arnd Bergmann 2010-02-25 692 pos = rcu_dereference(hlist_next_rcu(pos))) > 1cc523271ef0b63 stephen hemminger 2010-02-22 693 > 82524746c27fa41 Franck Bui-Huu 2008-05-12 694 /** > 82524746c27fa41 Franck Bui-Huu 2008-05-12 695 * hlist_for_each_entry_rcu - iterate over rcu list of given type > b67bfe0d42cac56 Sasha Levin 2013-02-27 696 * @pos: the type * to use as a loop cursor. > 82524746c27fa41 Franck Bui-Huu 2008-05-12 697 * @head: the head for your list. > 82524746c27fa41 Franck Bui-Huu 2008-05-12 698 * @member: the name of the hlist_node within the struct. > ddc465936643108 Jonathan Neuschäfer 2020-03-05 699 * @cond: optional lockdep expression if called from non-RCU protection. > 82524746c27fa41 Franck Bui-Huu 2008-05-12 700 * > 82524746c27fa41 Franck Bui-Huu 2008-05-12 701 * This list-traversal primitive may safely run concurrently with > 82524746c27fa41 Franck Bui-Huu 2008-05-12 702 * the _rcu list-mutation primitives such as hlist_add_head_rcu() > 82524746c27fa41 Franck Bui-Huu 2008-05-12 703 * as long as the traversal is guarded by rcu_read_lock(). > 82524746c27fa41 Franck Bui-Huu 2008-05-12 704 */ > 28875945ba98d1b Joel Fernandes (Google 2019-07-16 705) #define hlist_for_each_entry_rcu(pos, head, member, cond...) \ > 28875945ba98d1b Joel Fernandes (Google 2019-07-16 706) for (__list_check_rcu(dummy, ## cond, 0), \ > 28875945ba98d1b Joel Fernandes (Google 2019-07-16 707) pos = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),\ > b67bfe0d42cac56 Sasha Levin 2013-02-27 708 typeof(*(pos)), member); \ > b67bfe0d42cac56 Sasha Levin 2013-02-27 709 pos; \ > b67bfe0d42cac56 Sasha Levin 2013-02-27 710 pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(\ > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 711 &(pos)->member)), typeof(*(pos)), member)) > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 712 > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 713 /** > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 714 * hlist_for_each_entry_srcu - iterate over rcu list of given type > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 715 * @pos: the type * to use as a loop cursor. > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 716 * @head: the head for your list. > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 717 * @member: the name of the hlist_node within the struct. > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 718 * @cond: lockdep expression for the lock required to traverse the list. > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 719 * > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 720 * This list-traversal primitive may safely run concurrently with > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 721 * the _rcu list-mutation primitives such as hlist_add_head_rcu() > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 722 * as long as the traversal is guarded by srcu_read_lock(). > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 723 * The lockdep expression srcu_read_lock_held() can be passed as the > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 724 * cond argument from read side. > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 725 */ > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 726 #define hlist_for_each_entry_srcu(pos, head, member, cond) \ > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 @727 for (__list_check_srcu(cond), \ > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 728 pos = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),\ > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 729 typeof(*(pos)), member); \ > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 730 pos; \ > bd4444c47de914a Madhuparna Bhowmik 2020-07-12 731 pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(\ > b67bfe0d42cac56 Sasha Levin 2013-02-27 732 &(pos)->member)), typeof(*(pos)), member)) > 82524746c27fa41 Franck Bui-Huu 2008-05-12 733 > > :::::: The code at line 727 was first introduced by commit > :::::: bd4444c47de914a27b650f029d46efbbb6809765 rculist : Introduce list/hlist_for_each_entry_srcu() macros > > :::::: TO: Madhuparna Bhowmik > :::::: CC: Paul E. McKenney > > --- > 0-DAY CI Kernel Test Service, Intel Corporation > https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org