[LTP] Ocassional dropping of uevent of loop device (possible race)

[Cyril Hrubis]

Hi!
> commit 716ad0986cbd ("loop: Switch to set_capacity_revalidate_and_notify()")
> from v5.8-rc1 caused occasional dropping of uevent of attached or detached loop
> device (not sure which one). The only difference is that
> set_capacity_revalidate_and_notify() has condition:
> if (capacity != size && capacity != 0 && size != 0)
> thus notification is not triggered here but in a different part of code.
> 
> It was found with LTP test uevent01 [1]:
> 
> # i=0; while true; do i=$((i+1)); echo "== $i =="; rmmod -f loop; ./uevent01 || break; done
> 
> It looks to be a race. Usually ~ 10 loops is enough.

Looks like the link to test source is missing and should have been:

[1] https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/uevents/uevent01.c

-- 
Cyril Hrubis
chrubis@suse.cz