Re: WARNING: at kernel/workqueue.c:1473 __queue_work+0x3b8/0x3d0

[Daniel Jordan]

On Thu, Oct 01, 2020 at 07:50:22PM +0200, Corentin Labbe wrote:
> On Tue, Mar 03, 2020 at 04:30:17PM -0500, Daniel Jordan wrote:
> > Barring other ideas, Corentin, would you be willing to boot with
> > 
> >     trace_event=initcall:*,module:* trace_options=stacktrace
> > 
> > and
> > 
> > diff --git a/kernel/module.c b/kernel/module.c
> > index 33569a01d6e1..393be6979a27 100644
> > --- a/kernel/module.c
> > +++ b/kernel/module.c
> > @@ -3604,8 +3604,11 @@ static noinline int do_init_module(struct module *mod)
> >  	 * be cleaned up needs to sync with the queued work - ie
> >  	 * rcu_barrier()
> >  	 */
> > -	if (llist_add(&freeinit->node, &init_free_list))
> > +	if (llist_add(&freeinit->node, &init_free_list)) {
> > +		pr_warn("%s: schedule_work for mod=%s\n", __func__, mod->name);
> > +		dump_stack();
> >  		schedule_work(&init_free_wq);
> > +	}
> >  
> >  	mutex_unlock(&module_mutex);
> >  	wake_up_all(&module_wq);
> > 
> > but not my earlier fix and share the dmesg and ftrace output to see if the
> > theory holds?
> > 
> > Also, could you attach your config?  Curious now what your crypto options look
> > like after fiddling with some of them today while trying and failing to see
> > this on x86.
> > 
> > thanks,
> > Daniel
> 
> Hello
> 
> Sorry for the very delayed answer.
> 
> I fail to reproduce it on x86 (qemu and  real hw) and arm.
> It seems to only happen on arm64.

Thanks for the config and dmesg, but there's no ftrace.  I see it's not
configured in your kernel, so could you boot with my earlier debug patch plus
this one and the kernel argument initcall_debug instead?

I'm trying to see whether it really is a request module call from the crypto
tests that's triggering this warning.  Preeetty likely that's what's happening,
but want to be sure since I can't reproduce this.  Then I can post the fix.

diff --git a/crypto/algapi.c b/crypto/algapi.c
index fdabf2675b63..0667c6b4588e 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -393,6 +393,10 @@ static void crypto_wait_for_test(struct crypto_larval *larval)
 {
 	int err;
 
+	pr_warn("%s: cra_name %s cra_driver_name %s\n", __func__,
+		larval->adult->cra_name, larval->adult->cra_driver_name);
+	dump_stack();
+
 	err = crypto_probing_notify(CRYPTO_MSG_ALG_REGISTER, larval->adult);
 	if (err != NOTIFY_STOP) {
 		if (WARN_ON(err != NOTIFY_DONE))
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 3cd075ce2a1e..46c4645be763 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -166,6 +166,8 @@ int __request_module(bool wait, const char *fmt, ...)
 	}
 
 	trace_module_request(module_name, wait, _RET_IP_);
+	pr_warn("%s: %s\n", __func__, module_name);
+	dump_stack();
 
 	ret = call_modprobe(module_name, wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC);