From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9840733EC; Sun, 10 May 2026 04:02:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778385760; cv=none; b=WU60QIwRRZMrSyt8wOpxz0yWnrXrGJGWBRSLLqGoxOR71DRvxml01U/R96N3HB1h3eaZ2bX8X8HLLUuQe3gPsfhtLN+L2tX54KwR9hL+jpaKVsgBl7ViySgcXvFEjkistUzZypbQpZMcvMTyRRCB6d41h0oiNTyHVcFnkp9uIfw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778385760; c=relaxed/simple; bh=BEw1CTy1brhnwKWhO/MSoDJNn4pPxdnVj4m8F46EhBw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=DW7O8glG5jRNC3S2U5nC4xOoM7z89znTL8E2D32Zg31JU0B0m0eYVzb9aRYmpORiMCzNqPzmXjkXR1o7qKq8WPu2yz1qUeUPyI7hN1AIliOGWS1X7Ot+acBCxiW7lJ+bPfmkFky0kSacw+KJKqn/5bPGhLPQpt9sJnJ0RgT+yVk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ikc/odBM; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ikc/odBM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EFA58C2BCB8; Sun, 10 May 2026 04:02:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778385760; bh=BEw1CTy1brhnwKWhO/MSoDJNn4pPxdnVj4m8F46EhBw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Ikc/odBManXguIza9TjajNxrUzmqjavTC7CeBrvninNKE5hs8y5fxWfG8qpm9lFUQ AqqAcNXlLp93LMQ7F3hJZTa/amCMGQ79n/XwVC4UxyjLdnHQVxx1QmrXktPl4osroE M/ASwgSDQ2IBfp6k8pb2vnxFyduxp/03D1IqrYND4EDW9QdRwllSUO7vDLJi6rzu+y THYaQwJHOZ0GSRqeRJyDqMfIuy8qfiIY3SiwItLcCkFlvK7cPklodaY8KpCBPuuz6/ 3h7v077/yUO2dcGkP+y+NwcCCJj1BFzDWkV2diqPwP1B4Jyf1jAdVFEuSUuBrinugn B5R2K1k/H/0sg== Date: Sun, 10 May 2026 07:02:36 +0300 From: Jarkko Sakkinen To: Paul Moore , Eric Biggers Cc: David Howells , linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, syzkaller-bugs@googlegroups.com, syzbot Subject: Re: [syzbot] Monthly lsm report (Apr 2026) Message-ID: References: <69dde155.050a0220.3030df.004d.GAE@google.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Apr 14, 2026 at 10:02:13AM -0400, Paul Moore wrote: > > <2> 68 Yes possible deadlock in keyring_clear (3) > > https://syzkaller.appspot.com/bug?extid=f55b043dacf43776b50c > > Jarkko, David, > > Do we have a fix for the keyring_clear() issue, or is it not a real problem? Sorry for not meeting the timeline I promised. Anyhow, let's on the issue. There's really just two alternatives to resolve [1]: A. balance_pgdat() acquires keyring semaphore before __fs_reclaim_acquire(), and a non-locking-acquiring aking __keyring_clear() would be called inside fscrypt_put_master_key(). B. keyring_clear() is deferred and we accept that quota is not immediately released. Fixing this from the user process side doing kzalloc() is of course unrealistic, and unstable fix. So.. I don't think this is keyring issue per se. This is fscrypt issue mainly, aand depending on whether A or B are used to sort this out, possibly also kswapd issue. Or this is my analysis (which could be wrong of course) after couple hours looking into it. [1] https://lore.kernel.org/all/68e54915.a00a0220.298cc0.0480.GAE@google.com/T/ BR, Jarkko