[PATCH v2] sched: replace if (cond) BUG() with WARN_ON()

[Arnd Bergmann]

On Wed, Mar 17, 2021 at 8:35 AM Jiapeng Chong
<jiapeng.chong at linux.alibaba.com> wrote:
>
> Fix the following coccicheck warnings:
>
> ./arch/powerpc/platforms/cell/spufs/sched.c:908:2-5: WARNING: Use BUG_ON
> instead of if condition followed by BUG.
>
> Reported-by: Abaci Robot <abaci at linux.alibaba.com>
> Signed-off-by: Jiapeng Chong <jiapeng.chong at linux.alibaba.com>

If you change it from BUG() to WARN_ON(), you should explain why it's safe to
do that in this case. Here it is not, since the following spu_release() will
end up making things worse if the acquire failed. Also if there was a signal
pending, then spusched_tick() will just get called again and constantly
print these warnings.

There is probably a way to use WARN_ON_ONCE() here, in combination
with a way to terminate the thread safely, but this has to be done carefully.

       Arnd