Re: [PATCH] zram: protect recomp_algorithm_show() with ->init_lock

[Andrew Morton <akpm@linux-foundation.org>]

On Tue,  5 Aug 2025 19:19:29 +0900 Sergey Senozhatsky <senozhatsky@chromium.org> wrote:

> sysfs handlers should be called under ->init_lock and are not
> supposed to unlock it until return, otherwise e.g. a concurrent
> reset() can occur.  There is one handler that breaks that rule:
> recomp_algorithm_show().
> 
> Move ->init_lock handling outside of __comp_algorithm_show()
> (also drop it and call zcomp_available_show() directly) so that
> the entire recomp_algorithm_show() loop is protected by the
> lock, as opposed to protecting individual iterations.

As always, I'm wondering "does -stable need this".  But without knowing
the runtime effects of the bug, I cannot know.

Providing this info in the changelog would answer this for everyone, please.

> Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> Reported-by: Seyediman Seyedarab <imandevel@gmail.com>

And including a Closes: for Seyediman's report (if it's publicly
linkable) would be great too, thanks.

I'm guessing that a Fixes: isn't appropriate here because the
bug has been there since day 1.