Hi Qiang,
> From: Zqiang <qiang1.zhang@xxxxxxxxx>
> Sent: Monday, March 20, 2023 11:24 AM
> To: paulmck@xxxxxxxxxx; frederic@xxxxxxxxxx; joel@xxxxxxxxxxxxxxxxx
> Cc: rcu@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: [PATCH v2] rcutorture: Convert schedule_timeout_uninterruptible()
> to mdelay() in rcu_torture_stall()
>
> For kernels built with enable PREEMPT_NONE and
s/enable/enabling/
> CONFIG_DEBUG_ATOMIC_SLEEP, running the RCU stall tests.
s/running/run
>
> 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.
Tweak the commit description above to fix some grammar errors:
The above call trace occurred in the local_irq_disable/enable() critical section
when calling schedule_timeout() from rcu_torture_stall(). Invoking schedule_timeout()
also implies a quiescent state, of course, it also fails to trigger RCU stall. This commit,
therefore, uses mdelay() instead of schedule_timeout() to trigger the RCU stall.
> Suggested-by: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx>
> Signed-off-by: Zqiang <qiang1.zhang@xxxxxxxxx>
I didn't reproduce the call trace after applying your patch.
So, with the above minor fixes, then
Tested-by: Qiuxu Zhuo <qiuxu.zhuo@xxxxxxxxx>
Thanks
-Qiuxu
> ---
> 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..a08a72bef5f1 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(jiffies_to_msecs(HZ));
> #endif
> } else if (stall_no_softlockup) {
> touch_softlockup_watchdog();
> --
> 2.25.1
