From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) (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 EA2308472; Sun, 24 Nov 2024 18:19:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.89.141.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732472355; cv=none; b=UaRUpWipUnxZUS8y/VUFHi9Jge3Zt+fiddNCvAO7psHlPKSHfXzulWccoaco1u5cLeMSbaJL4dHWIt0u0kM6doSHb20AXKMXfLttUdIaDzjmOLi5Lg9EoYUep48N8uSVTIKe0aUdsE8UL/dAQSBab7ED5oTTOtikbBzbLQ0nPpk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732472355; c=relaxed/simple; bh=NrWBE+eVf6/bQnfDOwbINHP5NuRpko5suWSXSRKyxCo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fEQbYLMuFC76cD47dxLho6b+LSP+EACPcfTVdDfh9c2HYpAPwu+4wl0zZq4brLEXCKaeirVGQKpDhsG2l7ai6rdFMddORNTsQpa9kXyrC2HnyexUEv7Oq/rWsdpwsl48T5oWQS+zGeMlS2+EbWccbWCNdNtqIkT+aU+7PNceElY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk; spf=none smtp.mailfrom=ftp.linux.org.uk; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b=LFt4gkS4; arc=none smtp.client-ip=62.89.141.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=ftp.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b="LFt4gkS4" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=IvgTirpIcd/X+b0JRn0paS0cOSU5p0DJfQ0sxfqmEKU=; b=LFt4gkS4h0Gq2Eh3XpPrFiU279 MWwgzIJIbodTf3CsbMNQ4SxkdExvQAXkV2xMP/XsqtmdPXxZuRaKCJiz9kksAx2IXsaSJWo4y3wgw dl/+JzXh+oH8j18vL+udYm7G0hpI/hd10VlOrbMkUeAqlKco7sciKqkEMjm2MVt1263TVXc0iemg1 f5ow3WG6piB2SN+PGKYIEAKuesB9aSndf51A15Ls9hCSM8dUnT0fcHXAFcZRtmLsWIvAutG8o6gQe jXxNiRfczq9eMt18ofr+LVtNXv63qHFWelWlXAWK1K9gWcqKqDyFXslQxNQYvWlvrEiy8L3p5fWGR Fhmcmb1Q==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.98 #2 (Red Hat Linux)) id 1tFHCO-00000001HYh-44eI; Sun, 24 Nov 2024 18:19:09 +0000 Date: Sun, 24 Nov 2024 18:19:08 +0000 From: Al Viro To: Christian Brauner Cc: Linus Torvalds , Amir Goldstein , Miklos Szeredi , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 08/26] sev-dev: avoid pointless cred reference count bump Message-ID: <20241124181908.GV3387508@ZenIV> References: <20241124-work-cred-v1-0-f352241c3970@kernel.org> <20241124-work-cred-v1-8-f352241c3970@kernel.org> Precedence: bulk X-Mailing-List: linux-fsdevel@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: <20241124-work-cred-v1-8-f352241c3970@kernel.org> Sender: Al Viro On Sun, Nov 24, 2024 at 02:43:54PM +0100, Christian Brauner wrote: > drivers/crypto/ccp/sev-dev.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c > index 187c34b02442dd50640f88713bc5f6f88a1990f4..2e87ca0e292a1c1706a8e878285159b481b68a6f 100644 > --- a/drivers/crypto/ccp/sev-dev.c > +++ b/drivers/crypto/ccp/sev-dev.c > @@ -244,7 +244,7 @@ static struct file *open_file_as_root(const char *filename, int flags, umode_t m > if (!cred) > return ERR_PTR(-ENOMEM); > cred->fsuid = GLOBAL_ROOT_UID; > - old_cred = override_creds(get_new_cred(cred)); > + old_cred = override_creds(cred); > > fp = file_open_root(&root, filename, flags, mode); > path_put(&root); Looks sane, but the use of file reads/writes in there does not. At the very least, this nwrite = kernel_write(fp, sev_init_ex_buffer, NV_LENGTH, &offset); vfs_fsync(fp, 0); filp_close(fp, NULL); if (nwrite != NV_LENGTH) { dev_err(sev->dev, "SEV: failed to write %u bytes to non volatile memory area, ret %ld\n", NV_LENGTH, nwrite); return -EIO; } is either too much or too little - if it's serious about reporting errors, it would better check what fsync and close return... Oh, well - unrelated to your patchset, obviously