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 E9918A55; Sat, 8 Nov 2025 00:05:04 +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=1762560305; cv=none; b=CHmAwOkK8wxJNUIYoSTCViSZFIhaJOUqcFDbC6JtnR2GIHecEXN9jn3Z2oOKGdyhXWLFbL+OZOz8eX76PNbpUUyXGnnExzRaJc9nKXUPZCzvyd7blV5jkIuk3fZjsGVCIhnCNgv0DxWp1LM8oL6lb9ITnH+1Z4UPmb499S2oNKE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762560305; c=relaxed/simple; bh=Tqh33xIA4mgDa2BptdErXA8zNQ+Bw7zeLAuOimDde5Y=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=eFnvjxx6Z1tTGnSCL+EjCd9nZvuGV88YYLhCuG6zbzJ7017PPmW20zdARJOQCkr5VBnxEv5iP40BoCrRakAMmdqZK1KbdVgufnNwLwImJ/mcYgJyGYRoyIRnRaWiRQ+83IDWKhEP251eUqMc8k7wi0Gh58ziPEZIzYd0Xoj9+0E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b=bnxQLLsD; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="bnxQLLsD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CDFC2C116C6; Sat, 8 Nov 2025 00:05:02 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="bnxQLLsD" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1762560301; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=j317frlHa+Qx5iwhsewyfIq0wiwLQtpXQJB2BERP3GE=; b=bnxQLLsDNXzJcp27d6vn6WbaTpnp4mJTCJQnkxyMCWTRMwDUMaEbWAbEZBJKeaR63Y60o4 vso/1xejKtJMsUxye+W6brvjTz13PNV1PnFYrPOP8rBSQiZiIvDHjAhJf+nzNuwbxGFMok E++oXwA/NfcTlqtjhiSsW0aTB7KFiVs= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id b485aa65 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Sat, 8 Nov 2025 00:05:01 +0000 (UTC) Date: Sat, 8 Nov 2025 01:04:57 +0100 From: "Jason A. Donenfeld" To: Thiago Macieira Cc: Borislav Petkov , Christopher Snowhill , Gregory Price , x86@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com, peterz@infradead.org, mario.limonciello@amd.com, riel@surriel.com, yazen.ghannam@amd.com, me@mixaill.net, kai.huang@intel.com, sandipan.das@amd.com, darwi@linutronix.de, stable@vger.kernel.org Subject: Re: [PATCH v2] x86/amd: Disable RDSEED on AMD Zen5 because of an error. Message-ID: References: <2790505.9o76ZdvQCi@tjmaciei-mobl5> <27717271.1r3eYUQgxm@tjmaciei-mobl5> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <27717271.1r3eYUQgxm@tjmaciei-mobl5> On Fri, Nov 07, 2025 at 03:11:51PM -0800, Thiago Macieira wrote: > On Friday, 7 November 2025 15:07:13 Pacific Standard Time Jason A. Donenfeld > wrote: > > Oh. "Entropy source draining" is not a real thing. There used to be > > bizarre behavior related to /dev/random (not urandom), but this has been > > gone for ages. And even the non-getrandom Linux fallback code uses > > /dev/urandom before /dev/random. So not even on old kernels is this an > > issue. You can keep generating random numbers forever without worrying > > about running out of juice or irritating other processes. > > Thank you. This probably seals the deal. I'll prepare a patch removing the > direct use of the hardware instructions in the coming days. Cool. I've got an account on the Qt Gerrit (I think, anyway; it's been some years), in case it's useful to CC me. Jason