On Sun, Mar 19, 2023 at 8:28 PM Zqiang <qiang1.zhang@xxxxxxxxx> wrote: > > For kernels built with enable PREEMPT_NONE and CONFIG_DEBUG_ATOMIC_SLEEP, > running the RCU stall tests. > > runqemu kvm slirp nographic qemuparams="-m 1024 -smp 4" > bootparams="nokaslr console=ttyS0 rcutorture.stall_cpu=30 > rcutorture.stall_no_softlockup=1 rcutorture.stall_cpu_irqsoff=1 > rcutorture.stall_cpu_block=1" -d > > [ 10.841071] rcu-torture: rcu_torture_stall begin CPU stall > [ 10.841073] rcu_torture_stall start on CPU 3. > [ 10.841077] BUG: scheduling while atomic: rcu_torture_sta/66/0x0000000 > .... > [ 10.841108] Call Trace: > [ 10.841110] <TASK> > [ 10.841112] dump_stack_lvl+0x64/0xb0 > [ 10.841118] dump_stack+0x10/0x20 > [ 10.841121] __schedule_bug+0x8b/0xb0 > [ 10.841126] __schedule+0x2172/0x2940 > [ 10.841157] schedule+0x9b/0x150 > [ 10.841160] schedule_timeout+0x2e8/0x4f0 > [ 10.841192] schedule_timeout_uninterruptible+0x47/0x50 > [ 10.841195] rcu_torture_stall+0x2e8/0x300 > [ 10.841199] kthread+0x175/0x1a0 > [ 10.841206] ret_from_fork+0x2c/0x50 > > The above calltrace occurs in the local_irq_disable/enable() critical > section call schedule_timeout(), and invoke schedule_timeout() also > implies a quiescent state, of course it also fails to trigger RCU stall, > this commit therefore use mdelay() instead of schedule_timeout() to > trigger RCU stall. > > Signed-off-by: Zqiang <qiang1.zhang@xxxxxxxxx> > --- > kernel/rcu/rcutorture.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c > index d06c2da04c34..fe4f5a4074e3 100644 > --- a/kernel/rcu/rcutorture.c > +++ b/kernel/rcu/rcutorture.c > @@ -2472,7 +2472,7 @@ static int rcu_torture_stall(void *args) > #ifdef CONFIG_PREEMPTION > preempt_schedule(); > #else > - schedule_timeout_uninterruptible(HZ); > + mdelay(HZ); mdelay accepts milliseconds but HZ is jiffies correct? So this is broken for systems with HZ != 1000. So you need to call mdelay(jiffies_to_msecs(HZ)) instead. - Joel
