On 2022/3/5 4:28 上午, 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!
Hi Zhouyi, thanks for the bisection test. Could this patch solve RCU warning? I just tested on my machine and there is no RCU warning any more.
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 1e356c222756..0d1ada8968d7 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -450,6 +450,7 @@ extern struct mutex cgroup_mutex; extern spinlock_t css_set_lock; #define task_css_set_check(task, __c) \ rcu_dereference_check((task)->cgroups, \ + rcu_read_lock_sched_held() || \ lockdep_is_held(&cgroup_mutex) || \ lockdep_is_held(&css_set_lock) || \ ((task)->flags & PF_EXITING) || (__c))
Thanks.
On Sat, Mar 5, 2022 at 3:44 AM Paul E. McKenney paulmck@kernel.org 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, Paulgit reset --hard dc6e0818bc9a0336d9accf3ea35d146d72aa7a18 make -j 16 bindeb-pkg there are RCU WARNINGs: http://154.223.142.244/logs/20220305/log.dc6e0818bc9a0336d9accf3ea35d146d72a...
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.248cc9993d1cc12b8e9ed716cc3fc09f6c3...
Many thanks Zhouyi
Many thanks Zhouyi
On Fri, Mar 4, 2022 at 10:43 PM Naresh Kamboju naresh.kamboju@linaro.org 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@linaro.org
-- Linaro LKFT https://lkft.linaro.org
[1] https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20220304/tes...