From nobody Tue Nov 26 08:32:00 2024 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 A343D76C61; Fri, 18 Oct 2024 15:14:56 +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=1729264496; cv=none; b=JPudZrWNSMX2P8DbQtEkivvQIOBgRUodPny92fvHPm/YqeiJgXDtTxVH/EwsUXVFE2MJ3AlUoC7ZJvxpG+1cKeF7cahPt76v5m2pPHYIlG3S+Q7b2UtMTyyuev4O4yrTp+dyXICEMueczdPdIWT3qL2bFPGqxBkrDU5cF7Fj5rc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729264496; c=relaxed/simple; bh=wGv8jPPiROeuMxdNHPFP2YovhdUZEU8BVdG/fDTbVUk=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=cAoaq4UoXtpv6BrQsnSj1OthkqjwAQART9AMNGrKrhQhKoyte+ay3vDiB/WKNCAi+2vNZt/jwysHUnInMRuHDKtcoShEeGNXEmlHUfieldxX1T9rZNqEYwYqMo7wgmAbkBexkz3HTEHsJt5J89DrbXD/X9QbkqefZc+snW+3w50= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=r6v2Ui0I; 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="r6v2Ui0I" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F1663C4CEC3; Fri, 18 Oct 2024 15:14:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729264496; bh=wGv8jPPiROeuMxdNHPFP2YovhdUZEU8BVdG/fDTbVUk=; h=From:To:Cc:Subject:Date:From; b=r6v2Ui0IRj6XKF+J/obS7ioyIJ41+8RMhQmnTdTxUqxRwAMLyD5vNxrj7PQ2VLzwC xtB1VWF2Z9P/miSklSkUTBewkOX4YuyzipIFzjM7e1jgQ5xdDMHf6VHS3tU+Zoy6/C GhAMdJUVeeoqjupZi6bIpf+asTlNfChkyW2femw6bItSD70XgG5Y4K7FMFoIcZ5bRB /FiKp7QVVnPOpMCmEOfg7CIVL5/1SoMFgxeuPox10E89mW5R+GlQ15d7pB1+xgWsEs jgXZmxjX3Ojm1+yyrhP0XAJI8/HRzajHr1T4nrvzTlx26EUQ32IV4kVtjN3A6Lbwny 3S1m4tb2P3YgA== From: Arnd Bergmann To: Tiffany Lin , Andrew-CT Chen , Yunfei Dong , Mauro Carvalho Chehab , Matthias Brugger , AngeloGioacchino Del Regno , Nathan Chancellor Cc: Arnd Bergmann , Nick Desaulniers , Bill Wendling , Justin Stitt , Hans Verkuil , Sebastian Fricke , Benjamin Gaignard , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, llvm@lists.linux.dev Subject: [PATCH] media: mediatek: vcodec: mark vdec_vp9_slice_map_counts_eob_coef noinline Date: Fri, 18 Oct 2024 15:14:42 +0000 Message-Id: <20241018151448.3694052-1-arnd@kernel.org> X-Mailer: git-send-email 2.39.5 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Arnd Bergmann With KASAN enabled, clang fails to optimize the inline version of vdec_vp9_slice_map_counts_eob_coef() properly, leading to kilobytes of temporary values spilled to the stack: drivers/media/platform/mediatek/vcodec/decoder/vdec/vdec_vp9_req_lat_if.c:1= 526:12: error: stack frame size (2160) exceeds limit (2048) in 'vdec_vp9_sl= ice_update_prob' [-Werror,-Wframe-larger-than] This seems to affect all versions of clang including the latest (clang-20), but the degree of stack overhead is different per release. Marking the function as noinline_for_stack is harmless here and avoids the problem completely. Signed-off-by: Arnd Bergmann Reviewed-by: Nathan Chancellor --- I have not come to a conclusion on how exactly clang fails to do this right, but can provide the .config and/or preprocessed source files and command line if we think this should be fixed in clang. --- .../mediatek/vcodec/decoder/vdec/vdec_vp9_req_lat_if.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/media/platform/mediatek/vcodec/decoder/vdec/vdec_vp9_r= eq_lat_if.c b/drivers/media/platform/mediatek/vcodec/decoder/vdec/vdec_vp9_= req_lat_if.c index eea709d93820..47c302745c1d 100644 --- a/drivers/media/platform/mediatek/vcodec/decoder/vdec/vdec_vp9_req_lat_= if.c +++ b/drivers/media/platform/mediatek/vcodec/decoder/vdec/vdec_vp9_req_lat_= if.c @@ -1188,7 +1188,8 @@ static int vdec_vp9_slice_setup_lat(struct vdec_vp9_s= lice_instance *instance, return ret; } =20 -static +/* clang stack usage explodes if this is inlined */ +static noinline_for_stack void vdec_vp9_slice_map_counts_eob_coef(unsigned int i, unsigned int j, un= signed int k, struct vdec_vp9_slice_frame_counts *counts, struct v4l2_vp9_frame_symbol_counts *counts_helper) --=20 2.39.5