Messages in this thread | | | Date | Fri, 29 Jul 2022 13:18:49 +0800 | From | Oliver Sang <> | Subject | Re: [sched] 9ae606bc74: WARNING:at_kernel/rcu/rcutorture.c:#rcu_torture_stats_print[rcutorture] |
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hi Will,
On Mon, Jul 25, 2022 at 10:20:58AM +0100, Will Deacon wrote: > On Mon, Jul 25, 2022 at 04:12:57PM +0800, kernel test robot wrote: > > > > > > Greeting, > > > > FYI, we noticed the following commit (built with clang-15): > > > > commit: 9ae606bc74dd0e58d4de894e3c5cbb9d45599267 ("sched: Introduce task_cpu_possible_mask() to limit fallback rq selection") > > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master > > > > in testcase: rcutorture > > version: > > with following parameters: > > > > runtime: 300s > > test: cpuhotplug > > torture_type: trivial > > > > test-description: rcutorture is rcutorture kernel module load/unload test. > > test-url: https://www.kernel.org/doc/Documentation/RCU/torture.txt > > > > > > on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G > > > > caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): > > > > > > +-------------------------------------------------------------------------+------------+------------+ > > | | 304000390f | 9ae606bc74 | > > +-------------------------------------------------------------------------+------------+------------+ > > | WARNING:at_kernel/rcu/rcutorture.c:#synchronize_rcu_trivial[rcutorture] | 120 | 120 | > > | RIP:synchronize_rcu_trivial[rcutorture] | 120 | 120 | > > | WARNING:at_kernel/rcu/update.c:#rcutorture_sched_setaffinity | 120 | 120 | > > | RIP:rcutorture_sched_setaffinity | 120 | 120 | > > | WARNING:at_kernel/rcu/rcutorture.c:#rcu_torture_stats_print[rcutorture] | 0 | 36 | > > | RIP:rcu_torture_stats_print[rcutorture] | 0 | 36 | > > +-------------------------------------------------------------------------+------------+------------+ > > > > > > please be noted, since 9ae606bc74 is kind of old, we also tested on a latest > > mainline commit: > > commit 515f71412bb73ebd7f41f90e1684fc80b8730789 > > Merge: 301c8949322fe cf5029d5dd7cb > > Author: Linus Torvalds <torvalds@linux-foundation.org> > > Date: Sat Jul 23 10:22:26 2022 -0700 > > > > and confirmed the > > WARNING:at_kernel/rcu/rcutorture.c:#rcu_torture_stats_print[rcutorture] > > still exists. > > I'm not convinced by the bisection -- that commit should't have any effect > on x86.
Thanks a lot for your information! we will do some further tests to see if below part could impact x86. will update you next week. thanks
@@ -3124,9 +3124,7 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
/* Look for allowed, online CPU in same node. */ for_each_cpu(dest_cpu, nodemask) { - if (!cpu_active(dest_cpu)) - continue; - if (cpumask_test_cpu(dest_cpu, p->cpus_ptr)) + if (is_cpu_allowed(p, dest_cpu)) return dest_cpu; } }
> > Will
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