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 C075A13AA4C; Wed, 26 Jun 2024 17:06:08 +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=1719421568; cv=none; b=f7YyZ9wakvFgGmm+fYBfXe+RoZzVdtOtS84epiYhmexNGVLt2vInFZX/GkevYZKj4/yIir7GIvv6lT/gKByXF1bZdogDDXRG1avXWJYTEvdMC4h/D13IeabSnj0ClVv1xmS9CD2motJwS64uS3tvBXRLS0f5kZh+tuYcWmQahq4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719421568; c=relaxed/simple; bh=NGlqg/Pmt4gOfQtT4F33ND5D947m/+4mzw6M8io5Qtw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=cDC3gg8LU2484XuEL/KIvesD+9vWkj7fIJ5zgciXhqksncFZd9GReBlIRXqSCfg6shk8O7YvqzpkCtrh3yrzF9JzM4l7EPBqVnWNkhGuCqK+cl/uKNxzO/xDnoNLoAn3uGKVQpDu3bcAu4jVw78rVQlL8UrtHGJVRL2VfoeGek8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UfDdLa2S; 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="UfDdLa2S" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6287CC116B1; Wed, 26 Jun 2024 17:06:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1719421568; bh=NGlqg/Pmt4gOfQtT4F33ND5D947m/+4mzw6M8io5Qtw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UfDdLa2S1ysiOoxcviyR4sD9rKUYuwGOxvS6LdOZDp60i58O8O/zKNCx8xVqnx9Mw LmGDsy869BKdL+jUwonXLt/4TSeOgToxdM3UkkmnmgKeStZkvrDWD+HPg9nwV90kBw hqo4bf4F2QabTiTSb+kSwp0ey36OEiffBOG+YpQT3yxG2tf8dP8Nfa8MEXVqNoylDF tBzYbmIZb/DWI0qNqLL6MQ5eSEjdoqhJTYO7Scu2Sc978nDTaO0QlF0QEExjOYQSvP Zt+Fv7574L1eefswOYgYSBFZT+tIRYGWNzdwaj53LPSQWjCPgji+/zh1U7Vj6mhiwK IuGPIDjAcC4ug== Date: Wed, 26 Jun 2024 10:06:05 -0700 From: Nathan Chancellor To: James Smart , Christoph Hellwig , Sagi Grimberg , Chaitanya Kulkarni Cc: Kees Cook , "Gustavo A. R. Silva" , Bill Wendling , Justin Stitt , Keith Busch , linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, llvm@lists.linux.dev, patches@lists.linux.dev, stable@vger.kernel.org Subject: Re: [PATCH] nvmet-fc: Remove __counted_by from nvmet_fc_tgt_queue.fod[] Message-ID: <20240626170605.GA66745@fedora-macbook-air-m2> References: <20240529-drop-counted-by-fod-nvmet-fc-tgt-queue-v1-1-286adbc25943@kernel.org> Precedence: bulk X-Mailing-List: stable@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: <20240529-drop-counted-by-fod-nvmet-fc-tgt-queue-v1-1-286adbc25943@kernel.org> Ping? This is still relevant and I don't think this is a compiler bug that would justify withholding this change. On Wed, May 29, 2024 at 02:42:40PM -0700, Nathan Chancellor wrote: > Work for __counted_by on generic pointers in structures (not just > flexible array members) has started landing in Clang 19 (current tip of > tree). During the development of this feature, a restriction was added > to __counted_by to prevent the flexible array member's element type from > including a flexible array member itself such as: > > struct foo { > int count; > char buf[]; > }; > > struct bar { > int count; > struct foo data[] __counted_by(count); > }; > > because the size of data cannot be calculated with the standard array > size formula: > > sizeof(struct foo) * count > > This restriction was downgraded to a warning but due to CONFIG_WERROR, > it can still break the build. The application of __counted_by on the fod > member of 'struct nvmet_fc_tgt_queue' triggers this restriction, > resulting in: > > drivers/nvme/target/fc.c:151:2: error: 'counted_by' should not be applied to an array with element of unknown size because 'struct nvmet_fc_fcp_iod' is a struct type with a flexible array member. This will be an error in a future compiler version [-Werror,-Wbounds-safety-counted-by-elt-type-unknown-size] > 151 | struct nvmet_fc_fcp_iod fod[] __counted_by(sqsize); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > 1 error generated. > > Remove this use of __counted_by to fix the warning/error. However, > rather than remove it altogether, leave it commented, as it may be > possible to support this in future compiler releases. > > Cc: stable@vger.kernel.org > Closes: https://github.com/ClangBuiltLinux/linux/issues/2027 > Fixes: ccd3129aca28 ("nvmet-fc: Annotate struct nvmet_fc_tgt_queue with __counted_by") > Signed-off-by: Nathan Chancellor > --- > drivers/nvme/target/fc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c > index 337ee1cb09ae..381b4394731f 100644 > --- a/drivers/nvme/target/fc.c > +++ b/drivers/nvme/target/fc.c > @@ -148,7 +148,7 @@ struct nvmet_fc_tgt_queue { > struct workqueue_struct *work_q; > struct kref ref; > /* array of fcp_iods */ > - struct nvmet_fc_fcp_iod fod[] __counted_by(sqsize); > + struct nvmet_fc_fcp_iod fod[] /* __counted_by(sqsize) */; > } __aligned(sizeof(unsigned long long)); > > struct nvmet_fc_hostport { > > --- > base-commit: c758b77d4a0a0ed3a1292b3fd7a2aeccd1a169a4 > change-id: 20240529-drop-counted-by-fod-nvmet-fc-tgt-queue-50edd2f8d60e > > Best regards, > -- > Nathan Chancellor >