On 26 Apr 2022, at 17:08, Qian Cai wrote:

> On Tue, Apr 26, 2022 at 04:26:08PM -0400, Zi Yan wrote:
>> Thanks for reporting the issue. Do you have a reproducer I can use to debug the code?
>
> Nothing fancy. It just try to remove and add back each memory section.
>
> #!/usr/bin/env python3
> # SPDX-License-Identifier: GPL-2.0
>
> import os
> import re
> import subprocess
>
>
> def mem_iter():
>     base_dir = '/sys/devices/system/memory/'
>     for curr_dir in os.listdir(base_dir):
>         if re.match(r'memory\d+', curr_dir):
>             yield base_dir + curr_dir
>
>
> if __name__ == '__main__':
>     print('- Try to remove each memory section and then add it back.')
>     for mem_dir in mem_iter():
>         status = f'{mem_dir}/online'
>         if open(status).read().rstrip() == '1':
>             # This could expectedly fail due to many reasons.
>             section = os.path.basename(mem_dir)
>             print(f'- Try to remove {section}.')
>             proc = subprocess.run([f'echo 0 | sudo tee {status}'], shell=True)
>             if proc.returncode == 0:
>                 print(f'- Try to add {section}.')
>                 subprocess.check_call([f'echo 1 | sudo tee {status}'], shell=True)

Thanks. Do you mind attaching your config file? I cannot reproduce
the deadlock locally using my own config. I also see kmemleak_scan
in the dumped stack, so it must be something else in addition to
memory online/offline causing the issue.

--
Best Regards,
Yan, Zi