linux-kernel - Re: [PATCH 5/6] eventfs: get rid of dentry pointers without refcounts

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Tue, 30 Jan 2024 21:57:26 -0800
From: Linus Torvalds <torvalds@...ux-foundation.org>
To: Steven Rostedt <rostedt@...dmis.org>
Cc: Masami Hiramatsu <mhiramat@...nel.org>, linux-kernel@...r.kernel.org, 
	linux-trace-kernel@...r.kernel.org
Subject: Re: [PATCH 5/6] eventfs: get rid of dentry pointers without refcounts

On Tue, 30 Jan 2024 at 21:33, Steven Rostedt <rostedt@...dmis.org> wrote:
>
> With even the last patch included, without the d_invalidate() I get errors
> with simply doing:
>
>  # cd /sys/kernel/tracing
>  # mkdir instances/foo
>  # ls instances/foo/events
>  # rmdir instances/foo
>
> As the rmdir calls tracefs_remove() that calls simple_recursive_removal()
> that then walks into the "events" directory. Without that d_invalidate, it
> walks beyond just the top directory and then splats on the dentries that
> are cached.

Ugh.

This is only an issue for that "events" dir, right? The one that has a
proper refcount on the dentry in 'ei->events_dir'?

Because yes, then doing d_invalidate() looks like the right thing.

           Linus