Re: [next-20230322] Kernel WARN at kernel/workqueue.c:3182 (rcutorture)

On Thu, Mar 23, 2023 at 11:00:59PM +0530, Sachin Sant wrote:

quoted

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[ 3629.243407] NIP [00007fff8cd39558] 0x7fff8cd39558
[ 3629.243410] LR [000000010d800398] 0x10d800398
[ 3629.243413] --- interrupt: c00
[ 3629.243415] Code: 419dffa4 e93a0078 39400001 552907be 2f890000 7d20579e 0b090000 e95a0078 e91a0080 39200001 7fa85000 7d204f9e <0b090000> 7f23cb78 4bfffd65 0b030000 
[ 3629.243430] ---[ end trace 0000000000000000 ]—

These warnings are repeated few times. The LTP test is marked as PASS.

Git bisect point to the following patch
commit f46a5170e6e7d5f836f2199fe82cdb0b4363427f
   srcu: Use static init for statically allocated in-module srcu_struct

Hello, Sachin, and it looks like you hit something that Zqiang and I
have been tracking down.  I am guessing that you were using modprobe
and rmmod to make this happen, and that this happened at rmmod time.

Yes, the LTP test script rcu_torture.sh relies on modprobe to load/unload
the rcutorture module.

quoted

Whatever the reproducer, does the following patch help?

Thank you for the patch. Yes, with this patch applied, the test completes
successfully without the reported warning.

Very good, thank you!  May we have your Tested-by?

							Thanx, Paul