linux-kernel - Re: debugfs revoke broken?

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Message-ID: <ra3ig25pwua6wm6v7vqexjvwybfpk23i5qqfeihth4f3zygjb6@7ykqlkyu25tb>
Date: Mon, 15 Apr 2024 14:02:33 -0400
From: Kent Overstreet <kent.overstreet@...ux.dev>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Johannes Berg <johannes.berg@...el.com>, 
	linux-bcachefs@...r.kernel.org, linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: debugfs revoke broken?

On Mon, Apr 15, 2024 at 10:47:56AM +0200, Greg Kroah-Hartman wrote:
> So this file was open when debugfs_remove() was called?

Seems likely.

> Any chance you can bisect?  We just fixed some issues here in
> 952c3fce297f ("debugfs: fix wait/cancellation handling during remove")
> that I thought should have handled this.  If you revert that commit,
> does things work again?  And/or what about commit 8c88a474357e
> ("debugfs: add API to allow debugfs operations cancellation")?  Maybe we
> need to go back to not having completions at all in the debugfs remove
> path and just live with waiting for the files to be removed before
> continuing (which should at the least, resolve the issue you see here,
> while slowing things down a bit.)

No, this doesn't occur often enough to bisect, unfortunately. All my
tests bang on sysfs/debugfs in the background to torture test those
codepaths, and I've seen 2 occurrences out of thousands of test runs -
it's rare.