On Sat, Mar 05, 2022 at 04:28:51AM +0800, Zhouyi Zhou wrote: > Hi Paul > > Yes, your suggestion works! > Thank you for your guidance, this is the first time I ever did a > bisection, I gained greatly during this process! > > On Sat, Mar 5, 2022 at 3:44 AM Paul E. McKenney <paulmck@xxxxxxxxxx> wrote: > > > > On Sat, Mar 05, 2022 at 03:38:33AM +0800, Zhouyi Zhou wrote: > > > Hi, > > > I can reproduce these warnings on my X86 VM. > > > Following the my backtrace: > > > > > > (gdb) bt > > > #0 lockdep_rcu_suspicious (file=file@entry=0xffffffff825ea8ff > > > "include/linux/cgroup.h", line=line@entry=494, > > > s=s@entry=0xffffffff825c5c50 "suspicious rcu_dereference_check() > > > usage") at ./arch/x86/include/asm/current.h:15 > > > #1 0xffffffff81183103 in task_css (subsys_id=2, > > > task=0xffff888100804080) at ./include/linux/cgroup.h:494 > > > #2 task_ca (tsk=0xffff888100804080) at kernel/sched/cpuacct.c:40 > > > #3 cpuacct_charge (tsk=tsk@entry=0xffff888100804080, > > > cputime=cputime@entry=3344803) at kernel/sched/cpuacct.c:342 > > > #4 0xffffffff81162655 in cgroup_account_cputime (delta_exec=3344803, > > > task=0xffff888100804080) at ./include/linux/cgroup.h:792 > > > #5 update_curr (cfs_rq=cfs_rq@entry=0xffff88813b63f500) at > > > kernel/sched/fair.c:907 > > > #6 0xffffffff81164797 in dequeue_entity (flags=10, > > > se=0xffff888100804100, cfs_rq=0xffff88813b63f500) at > > > kernel/sched/fair.c:5771 > > > #7 dequeue_task_fair (rq=0xffff88813b63f440, p=0xffff888100804080, > > > flags=10) at kernel/sched/fair.c:5771 > > > #8 0xffffffff8115412a in dequeue_task (flags=10, > > > p=0xffff888100804080, rq=0xffff88813b63f440) at > > > kernel/sched/core.c:2019 > > > #9 __do_set_cpus_allowed (p=0xffff888100804080, > > > new_mask=0xffffffff831b4d40 <housekeeping+512>, flags=0) at > > > kernel/sched/core.c:2508 > > > #10 0xffffffff811564ca in __set_cpus_allowed_ptr_locked > > > (p=p@entry=0xffff888100804080, > > > new_mask=new_mask@entry=0xffffffff831b4d40 <housekeeping+512>, > > > flags=flags@entry=0, rq=0xffff88813b63f440, > > > rf=rf@entry=0xffffc9000012bee8) at kernel/sched/core.c:2841 > > > #11 0xffffffff81156573 in __set_cpus_allowed_ptr > > > (p=p@entry=0xffff888100804080, new_mask=0xffffffff831b4d40 > > > <housekeeping+512>, flags=flags@entry=0) > > > at kernel/sched/core.c:2874 > > > #12 0xffffffff8115664c in set_cpus_allowed_ptr > > > (p=p@entry=0xffff888100804080, new_mask=<optimized out>) at > > > kernel/sched/core.c:2879 > > > #13 0xffffffff81144676 in kthreadd (unused=<optimized out>) at > > > kernel/kthread.c:724 > > > #14 0xffffffff810019df in ret_from_fork () at arch/x86/entry/entry_64.S:295 > > > #15 0x0000000000000000 in ?? () > > > > > > Do the warnings have something to do with commit > > > dc6e0818bc9a0336d9accf3ea35d146d72aa7a18 (sched/cpuacct: Optimize away > > > RCU read lock) ? > > > > If you have not already done so, could you please try running on this > > commit and then on the commit immediately preceding it? Just as a > > authoritative way to answer your question. ;-) > > > > Thanx, Paul > > > git reset --hard dc6e0818bc9a0336d9accf3ea35d146d72aa7a18 > make -j 16 bindeb-pkg > there are RCU WARNINGs: > http://154.223.142.244/logs/20220305/log.dc6e0818bc9a0336d9accf3ea35d146d72aa7a18.txt > > then I running on the commit immediately preceding it > git reset --hard 248cc9993d1cc12b8e9ed716cc3fc09f6c3517dd > make -j 16 bindeb-pkg > the WARNINGs are gone with the wind ;-) > http://154.223.142.244/logs/20220305/log.248cc9993d1cc12b8e9ed716cc3fc09f6c3517dd.txt That does look convincing. ;-) Adding that patch's author, Chengming Zhou, on CC. (Feel free to do this yourself next time around.) Thanx, Paul > Many thanks > Zhouyi > > > Many thanks > > > Zhouyi > > > > > > On Fri, Mar 4, 2022 at 10:43 PM Naresh Kamboju > > > <naresh.kamboju@xxxxxxxxxx> wrote: > > > > > > > > While booting x86_64 with linux next-20220304 kernel the following kernel > > > > warning reported [1]. > > > > > > > > metadata: > > > > git_ref: master > > > > git_repo: https://gitlab.com/Linaro/lkft/mirrors/next/linux-next > > > > git_sha: 6d284ba80c0c485bcaa7bdf67f232d572640edc4 > > > > git_describe: next-20220304 > > > > kernel-config: https://builds.tuxbuild.com/25uuYdm2vTO275aZ3IewZY5sKbU/config > > > > > > > > > > > > warning log: > > > > --------- > > > > [ 1.482171] MDS: Mitigation: Clear CPU buffers > > > > [ 1.485680] Freeing SMP alternatives memory: 52K > > > > [ 1.487341] > > > > [ 1.488169] ============================= > > > > [ 1.488169] WARNING: suspicious RCU usage > > > > [ 1.488169] 5.17.0-rc6-next-20220304 #1 Not tainted > > > > [ 1.488169] ----------------------------- > > > > [ 1.488169] include/linux/cgroup.h:494 suspicious > > > > rcu_dereference_check() usage! > > > > [ 1.488169] > > > > [ 1.488169] other info that might help us debug this: > > > > [ 1.488169] > > > > [ 1.488169] > > > > [ 1.488169] rcu_scheduler_active = 1, debug_locks = 1 > > > > [ 1.488169] 2 locks held by kthreadd/2: > > > > [ 1.488169] #0: ffff9ba440352330 (&p->pi_lock){....}-{2:2}, at: > > > > task_rq_lock+0x2e/0x130 > > > > [ 1.488169] #1: ffff9ba7a7a2d058 (&rq->__lock){-...}-{2:2}, at: > > > > task_rq_lock+0x5d/0x130 > > > > [ 1.488169] > > > > [ 1.488169] stack backtrace: > > > > [ 1.488169] CPU: 0 PID: 2 Comm: kthreadd Not tainted > > > > 5.17.0-rc6-next-20220304 #1 > > > > [ 1.488169] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS > > > > 2.5 11/26/2020 > > > > [ 1.488169] Call Trace: > > > > [ 1.488169] <TASK> > > > > [ 1.488169] dump_stack_lvl+0x49/0x5e > > > > [ 1.488169] dump_stack+0x10/0x12 > > > > [ 1.488169] lockdep_rcu_suspicious+0xed/0xf8 > > > > [ 1.488169] cpuacct_charge+0x10c/0x120 > > > > [ 1.488169] update_curr+0x165/0x340 > > > > [ 1.488169] dequeue_entity+0x23/0x430 > > > > [ 1.488169] dequeue_task_fair+0xba/0x3b0 > > > > [ 1.488169] __do_set_cpus_allowed+0xca/0x2c0 > > > > [ 1.488169] __set_cpus_allowed_ptr_locked+0x128/0x1b0 > > > > [ 1.488169] set_cpus_allowed_ptr+0x43/0x70 > > > > [ 1.488169] kthreadd+0x49/0x230 > > > > [ 1.488169] ? kthread_is_per_cpu+0x30/0x30 > > > > [ 1.488169] ret_from_fork+0x22/0x30 > > > > [ 1.488169] </TASK> > > > > [ 1.488169] > > > > [ 1.488169] ============================= > > > > [ 1.488169] WARNING: suspicious RCU usage > > > > [ 1.488169] 5.17.0-rc6-next-20220304 #1 Not tainted > > > > [ 1.488169] ----------------------------- > > > > [ 1.488169] include/linux/cgroup.h:481 suspicious > > > > rcu_dereference_check() usage! > > > > [ 1.488169] > > > > [ 1.488169] other info that might help us debug this: > > > > [ 1.488169] > > > > [ 1.488169] > > > > [ 1.488169] rcu_scheduler_active = 1, debug_locks = 1 > > > > [ 1.488169] 2 locks held by kthreadd/2: > > > > [ 1.488169] #0: ffff9ba440352330 (&p->pi_lock){....}-{2:2}, at: > > > > task_rq_lock+0x2e/0x130 > > > > [ 1.488169] #1: ffff9ba7a7a2d058 (&rq->__lock){-...}-{2:2}, at: > > > > task_rq_lock+0x5d/0x130 > > > > [ 1.488169] > > > > [ 1.488169] stack backtrace: > > > > [ 1.488169] CPU: 0 PID: 2 Comm: kthreadd Not tainted > > > > 5.17.0-rc6-next-20220304 #1 > > > > [ 1.488169] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS > > > > 2.5 11/26/2020 > > > > [ 1.488169] Call Trace: > > > > [ 1.488169] <TASK> > > > > [ 1.488169] dump_stack_lvl+0x49/0x5e > > > > [ 1.488169] dump_stack+0x10/0x12 > > > > [ 1.488169] lockdep_rcu_suspicious+0xed/0xf8 > > > > [ 1.488169] update_curr+0x2b7/0x340 > > > > [ 1.488169] dequeue_entity+0x23/0x430 > > > > [ 1.488169] dequeue_task_fair+0xba/0x3b0 > > > > [ 1.488169] __do_set_cpus_allowed+0xca/0x2c0 > > > > [ 1.488169] __set_cpus_allowed_ptr_locked+0x128/0x1b0 > > > > [ 1.488169] set_cpus_allowed_ptr+0x43/0x70 > > > > [ 1.488169] kthreadd+0x49/0x230 > > > > [ 1.488169] ? kthread_is_per_cpu+0x30/0x30 > > > > [ 1.488169] ret_from_fork+0x22/0x30 > > > > [ 1.488169] </TASK> > > > > [ 1.488169] > > > > [ 1.488169] ============================= > > > > [ 1.488169] WARNING: suspicious RCU usage > > > > [ 1.488169] 5.17.0-rc6-next-20220304 #1 Not tainted > > > > [ 1.488169] ----------------------------- > > > > [ 1.488169] include/linux/cgroup.h:481 suspicious > > > > rcu_dereference_check() usage! > > > > [ 1.488169] > > > > [ 1.488169] other info that might help us debug this: > > > > [ 1.488169] > > > > [ 1.488169] > > > > [ 1.488169] rcu_scheduler_active = 1, debug_locks = 1 > > > > [ 1.488169] no locks held by kthreadd/2. > > > > [ 1.488169] > > > > [ 1.488169] stack backtrace: > > > > [ 1.488169] CPU: 0 PID: 2 Comm: kthreadd Not tainted > > > > 5.17.0-rc6-next-20220304 #1 > > > > [ 1.488169] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS > > > > 2.5 11/26/2020 > > > > [ 1.488169] Call Trace: > > > > [ 1.488169] <IRQ> > > > > [ 1.488169] dump_stack_lvl+0x49/0x5e > > > > [ 1.488169] dump_stack+0x10/0x12 > > > > [ 1.488169] lockdep_rcu_suspicious+0xed/0xf8 > > > > [ 1.488169] account_system_index_time+0x127/0x130 > > > > [ 1.488169] account_system_time+0x50/0x60 > > > > [ 1.488169] account_process_tick+0x59/0x80 > > > > [ 1.488169] update_process_times+0x58/0xe0 > > > > [ 1.488169] tick_periodic+0x37/0xf0 > > > > [ 1.488169] tick_handle_periodic+0x24/0x70 > > > > [ 1.488169] timer_interrupt+0x18/0x20 > > > > [ 1.488169] __handle_irq_event_percpu+0x95/0x2f0 > > > > [ 1.488169] handle_irq_event+0x39/0x80 > > > > [ 1.488169] handle_edge_irq+0xa4/0x240 > > > > [ 1.488169] __common_interrupt+0x8d/0x170 > > > > [ 1.488169] common_interrupt+0xbd/0xe0 > > > > [ 1.488169] </IRQ> > > > > [ 1.488169] <TASK> > > > > [ 1.488169] asm_common_interrupt+0x1e/0x40 > > > > [ 1.488169] RIP: 0010:_raw_spin_unlock_irqrestore+0x37/0x60 > > > > [ 1.488169] Code: fc 48 83 c7 18 53 48 89 f3 48 8b 75 08 e8 21 83 > > > > ed fe 4c 89 e7 e8 19 b0 ed fe 80 e7 02 74 06 e8 6f 77 fa fe fb bf 01 > > > > 00 00 00 <e8> 24 6b e9 fe 65 8b 05 bd e1 28 66 85 c0 74 05 5b 41 5c 5d > > > > c3 0f > > > > [ 1.488169] RSP: 0000:ffffb75b0002fd50 EFLAGS: 00000202 > > > > [ 1.488169] RAX: 0000000000000007 RBX: 0000000000000246 RCX: 0000000000000000 > > > > [ 1.488169] RDX: 0000000000000000 RSI: ffffffff9a800a7c RDI: 0000000000000001 > > > > [ 1.488169] RBP: ffffb75b0002fd60 R08: 0000000000000001 R09: 0000000000000001 > > > > [ 1.488169] R10: 0000000000000002 R11: 0000000000000001 R12: ffff9ba440352318 > > > > [ 1.488169] R13: 0000000000000000 R14: 0000000000000000 R15: ffff9ba7a7a2d040 > > > > [ 1.488169] affine_move_task+0x2d4/0x5d0 > > > > [ 1.488169] ? __this_cpu_preempt_check+0x13/0x20 > > > > [ 1.488169] ? lock_is_held_type+0xdd/0x130 > > > > [ 1.488169] ? enqueue_entity+0x1b8/0x520 > > > > [ 1.488169] __set_cpus_allowed_ptr_locked+0x15c/0x1b0 > > > > [ 1.488169] set_cpus_allowed_ptr+0x43/0x70 > > > > [ 1.488169] kthreadd+0x49/0x230 > > > > [ 1.488169] ? kthread_is_per_cpu+0x30/0x30 > > > > [ 1.488169] ret_from_fork+0x22/0x30 > > > > [ 1.488169] </TASK> > > > > [ 1.489211] smpboot: Estimated ratio of average max frequency by > > > > base frequency (times 1024): 1126 > > > > [ 1.490189] smpboot: CPU0: Intel(R) Xeon(R) CPU E3-1220 v6 @ > > > > 3.00GHz (family: 0x6, model: 0x9e, stepping: 0x9) > > > > [ 1.491635] cblist_init_generic: Setting adjustable number of > > > > callback queues. > > > > [ 1.492171] cblist_init_generic: Setting shift to 2 and lim to 1. > > > > [ 1.493226] cblist_init_generic: Setting shift to 2 and lim to 1. > > > > [ 1.494226] cblist_init_generic: Setting shift to 2 and lim to 1. > > > > [ 1.495219] Running RCU-tasks wait API self tests > > > > [ 1.598317] Performance Events: PEBS fmt3+, Skylake events, 32-deep > > > > LBR, full-width counters, Intel PMU driver. > > > > [ 1.599176] ... version: 4 > > > > [ 1.600171] ... bit width: 48 > > > > [ 1.601171] ... generic registers: 8 > > > > [ 1.602171] ... value mask: 0000ffffffffffff > > > > [ 1.603171] ... max period: 00007fffffffffff > > > > [ 1.604176] ... fixed-purpose events: 3 > > > > [ 1.605171] ... event mask: 00000007000000ff > > > > [ 1.606188] Callback from call_rcu_tasks_trace() invoked. > > > > [ 1.607450] rcu: Hierarchical SRCU implementation. > > > > [ 1.608310] > > > > [ 1.609169] ============================= > > > > [ 1.609169] WARNING: suspicious RCU usage > > > > [ 1.609169] 5.17.0-rc6-next-20220304 #1 Not tainted > > > > [ 1.609169] ----------------------------- > > > > [ 1.609169] include/linux/cgroup.h:481 suspicious > > > > rcu_dereference_check() usage! > > > > [ 1.609169] > > > > [ 1.609169] other info that might help us debug this: > > > > [ 1.609169] > > > > [ 1.609169] > > > > [ 1.609169] rcu_scheduler_active = 1, debug_locks = 1 > > > > [ 1.609169] 1 lock held by migration/0/17: > > > > [ 1.609169] #0: ffff9ba7a7a2d058 (&rq->__lock){-.-.}-{2:2}, at: > > > > __schedule+0x12d/0xcb0 > > > > [ 1.609169] > > > > [ 1.609169] stack backtrace: > > > > [ 1.609169] CPU: 0 PID: 17 Comm: migration/0 Not tainted > > > > 5.17.0-rc6-next-20220304 #1 > > > > [ 1.609169] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS > > > > 2.5 11/26/2020 > > > > [ 1.609169] Stopper: 0x0 <- 0x0 > > > > [ 1.609169] Call Trace: > > > > [ 1.609169] <TASK> > > > > [ 1.609169] dump_stack_lvl+0x49/0x5e > > > > [ 1.609169] dump_stack+0x10/0x12 > > > > [ 1.609169] lockdep_rcu_suspicious+0xed/0xf8 > > > > [ 1.609169] put_prev_task_stop+0x1dc/0x240 > > > > [ 1.609169] __schedule+0x751/0xcb0 > > > > [ 1.609169] ? trace_preempt_off+0x29/0xc0 > > > > [ 1.609169] ? smpboot_thread_fn+0x33/0x290 > > > > [ 1.609169] schedule+0x58/0xc0 > > > > [ 1.609169] smpboot_thread_fn+0xec/0x290 > > > > [ 1.609169] ? sort_range+0x30/0x30 > > > > [ 1.609169] kthread+0x107/0x130 > > > > [ 1.609169] ? kthread_complete_and_exit+0x20/0x20 > > > > [ 1.609169] ret_from_fork+0x22/0x30 > > > > [ 1.609169] </TASK> > > > > [ 1.610276] smp: Bringing up secondary CPUs ... > > > > [ 1.611596] x86: Booting SMP configuration: > > > > [ 1.612179] .... node #0, CPUs: #1 #2 #3 > > > > [ 1.614396] smp: Brought up 1 node, 4 CPUs > > > > > > > > Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx> > > > > > > > > -- > > > > Linaro LKFT > > > > https://lkft.linaro.org > > > > > > > > [1] https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20220304/testrun/8235955/suite/linux-log-parser/test/check-kernel-warning-4655400/log
