On Fri, 19 Aug 2022 21:16:31 +0000 SeongJae Park <sj@xxxxxxxxxx> wrote: > > It would be simpler (and less racy) to check the debugfs_create_dir() > > return value for IS_ERR()? > > I was merely following Greg's previous advice for ignoring the return value[1] > of the function, but I might misunderstanding his intention, so CC-ing Greg. > Greg, may I ask your opinion? > > [1] https://lore.kernel.org/linux-mm/YB1kZaD%2F7omxXztF@xxxxxxxxx/ Thing is, the correct functioning of the debugfs interfaces is utterly critical to damon. And that's apart from these memory leak and oops-we-killed-damon issues. So damon simply cannot ignore the state of its debugfs interfaces and keep going along - because if something goes wrong at the debugfs layer, damon is dead and useless and the machine needs a reboot. Perhaps this means that damon should not be using debugfs for its interfaces at all. Or it means that the debugfs interfaces are misdesigned. I go with the latter, which, alas, also affirms the former. >From a quick scan it appears that a significant minority (20%?) of drivers are checking the debugfs_create_dir() return value.
