Received-SPF: pass (google.com: domain of linux-crypto+bounces-4335-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) client-ip=147.75.199.223;
Date: Wed, 22 May 2024 15:19:21 -0400
From: =?utf-8?B?TsOtY29sYXMgRi4gUi4gQS4=?= Prado <nfraprado@collabora.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Eric Biggers <ebiggers@kernel.org>, Jarkko Sakkinen <jarkko@kernel.org>,
	James Bottomley <James.Bottomley@hansenpartnership.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
	linux-integrity@vger.kernel.org, keyrings@vger.kernel.org,
	regressions@lists.linux.dev, kernel@collabora.com,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Tejun Heo <tj@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Kees Cook <keescook@chromium.org>
Subject: Re: [v3 PATCH] hwrng: core - Remove add_early_randomness
Message-ID: <3a6fe46c-f4cc-47a3-8ef3-ac07bde14ca1@notapiano>
References: <CAMj1kXFE_R_x10BVkU+8vrMz0RHiX0+rz-ZL+w08FH2CLQHZXA@mail.gmail.com>
 <66ec985f3ee229135bf748f1b0874d5367a74d7f.camel@HansenPartnership.com>
 <dfb0d930-7cbe-46c5-be19-d132b4906ecf@notapiano>
 <D1C2NPOBHAHK.20O4IME8OK1FH@kernel.org>
 <20240518043115.GA53815@sol.localdomain>
 <ZkhS1zrobNwAuANI@gondor.apana.org.au>
 <00bcfa65-384d-46ae-ab8b-30f12487928b@notapiano>
 <ZkwMnrTR_CbXcjWe@gondor.apana.org.au>
 <07512097-8198-4a84-b166-ef9809c2913b@notapiano>
 <Zk2Eso--FVsZ5AF3@gondor.apana.org.au>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <Zk2Eso--FVsZ5AF3@gondor.apana.org.au>

On Wed, May 22, 2024 at 01:37:54PM +0800, Herbert Xu wrote:
> On Tue, May 21, 2024 at 03:37:16PM -0400, N?colas F. R. A. Prado wrote:
> >
> > FWIW this patch fixes the warning. So feel free to add
> > 
> > Tested-by: N?colas F. R. A. Prado <nfraprado@collabora.com>
> 
> Could you please test this patch instead?
> 
> ---8<---
> A potential deadlock was reported with the config file at
> 
> https://web.archive.org/web/20240522052129/https://0x0.st/XPN_.txt
> 
> In this particular configuration, the deadlock doesn't exist because
> the warning triggered at a point before modules were even available.
> However, the deadlock can be real because any module loaded would
> invoke async_synchronize_full.
> 
> The issue is spurious for software crypto algorithms which aren't
> themselves involved in async probing.  However, it would be hard to
> avoid for a PCI crypto driver using async probing.
> 
> In this particular call trace, the problem is easily avoided because
> the only reason the module is being requested during probing is the
> add_early_randomness call in the hwrng core.  This feature is
> vestigial since there is now a kernel thread dedicated to doing
> exactly this.
> 
> So remove add_early_randomness as it is no longer needed.
> 
> Reported-by: N?colas F. R. A. Prado <nfraprado@collabora.com>
> Reported-by: Eric Biggers <ebiggers@kernel.org>
> Fixes: 1b6d7f9eb150 ("tpm: add session encryption protection to tpm2_get_random()")
> Link: https://lore.kernel.org/r/119dc5ed-f159-41be-9dda-1a056f29888d@notapiano/
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

This patch also fixes the warning.

Tested-by: N?colas F. R. A. Prado <nfraprado@collabora.com>

Thanks,
N?colas