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SubjectRe: [rcutorture] 613b00fbe6: WARNING:at_kernel/rcu/rcutorture.c:#rcu_torture_fwd_prog_cr[rcutorture]
On Wed, Aug 03, 2022 at 11:05:12PM +0800, kernel test robot wrote:
>
> (please be noted we reported this since clean on parent, ~10% on this commit,
> and found similar issue on latest maineline, e.g. v5.19)
>
>
> Greeting,
>
> FYI, we noticed the following commit (built with gcc-11):
>
> commit: 613b00fbe64461f1c73e035e07c22cf3de65740b ("rcutorture: Add ability to limit callback-flood intensity")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
>
> in testcase: rcutorture
> version:
> with following parameters:
>
> runtime: 300s
> test: default
> torture_type: tasks-tracing
>
> 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

I believe that this commit in -rcu fixes this problem. Could you please
check it?

Thanx, Paul

------------------------------------------------------------------------

commit dba268ff32101559cd3e3800b24993ae5c59844c
Author: Zqiang <qiang1.zhang@intel.com>
Date: Sun Jul 31 18:53:56 2022 +0800

rcutorture: Use the barrier operation specified by cur_ops

The rcutorture_oom_notify() function unconditionally invokes
rcu_barrier(), which is OK when the rcutorture.torture_type value is
"rcu", but unhelpful otherwise. The purpose of these barrier calls is to
wait for all outstanding callback-flooding callbacks to be invoked before
cleaning up their data. Using the wrong barrier function therefore
risks arbitrary memory corruption. Thus, this commit changes these
rcu_barrier() calls into cur_ops->cb_barrier() to make things work when
torturing non-vanilla flavors of RCU.

Signed-off-by: Zqiang <qiang1.zhang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 7168dc8d61e98..bdd630f7a970c 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -2603,12 +2603,12 @@ static int rcutorture_oom_notify(struct notifier_block *self,
for (i = 0; i < fwd_progress; i++)
ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
- rcu_barrier();
+ cur_ops->cb_barrier();
ncbs = 0;
for (i = 0; i < fwd_progress; i++)
ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
- rcu_barrier();
+ cur_ops->cb_barrier();
ncbs = 0;
for (i = 0; i < fwd_progress; i++)
ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
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