From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f51.google.com (mail-ot1-f51.google.com [209.85.210.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 043B33254A9 for ; Mon, 16 Mar 2026 19:37:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773689859; cv=none; b=BNaQnCty5RYDHyMlx+ObtiLlJw4gJ+RRahnsj6nnFmNQnhjoVBP8UlmTmgBFW6Suz3b/yQJ0CzCDVmCa/tNSCsrYj7jE09xaNeO/OaKRdDa/XWA3ZYd5RVXjVB9oqp1WMMx7N7Cdk0YvisaeWEG7vztXpFcmra9kSgvRyqFodLo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773689859; c=relaxed/simple; bh=ZvsXSyiI3XkbsKZuNkcSgsTni+v4WLMdb2x9NUrXcM4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=h3pCAyt26X/2IJCi2zkD7tUPBqMlo27cg7Ilo96XEYcA0JtNYlubLi4AAHQCg3PbcM0uqgJV/y2VrIK3o6T8GZbnoDWfWgrMIkhFSWc2h0H0214ArP3QldI/L/NGQWRUfpMst7zLmglAPP/5NfHbezLkwH3j8qkLtKCVDoorJ5s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk; spf=pass smtp.mailfrom=kernel.dk; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b=V9gJGEMJ; arc=none smtp.client-ip=209.85.210.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kernel.dk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b="V9gJGEMJ" Received: by mail-ot1-f51.google.com with SMTP id 46e09a7af769-7d1872504cbso69603a34.0 for ; Mon, 16 Mar 2026 12:37:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1773689857; x=1774294657; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=yTI4ZGyhMvb0csBBlNJg9TpIQ4OoSUyId0bqLGFvRG4=; b=V9gJGEMJeyQPEUQoq9izwPN833JdTjNkNnsg4VZ/+fCFTH48JFcd8wv+fsWT8ST/yU klaxnuhF6HFEsSdeMgQwqanoKL/qJ+quPTuHr3gYGCAp0XmpMvHHkKjPCK6R6sv7tm3m vjvFoOi2OItk0dQPsz6Uj1UvINuWVdab+kma3F7x2JkQUD9rVR+ddS65zDiAYR8RfJsr pxr7ojJq5IHyxUtV8KJ2jMkKbj4jjyRyzF67oaCRQ0hFY1J4WZsFggqVVpDz0tnOplVD OGQYZliyau63hDIggJOS/5aPQi4M+OC+t0xjnvbEdbKeZUpLs1MqwiH2Fhmw9m7x8Ra7 BWbQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1773689857; x=1774294657; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=yTI4ZGyhMvb0csBBlNJg9TpIQ4OoSUyId0bqLGFvRG4=; b=lXuZnhEh/7LMSCl1X7DjHGYbhIY8GuPGTO05e612bZEKA8q6ajwnPt66MG8UlqRzZJ 6/qW5PBj9KnqsuP59nMUqej/Zg+wijX8zvCgiHAgS8WBxwvl+tQ+zTskrjcXLK9pcqp3 l5znPXzrANiyuWNtm8GlTdTSwpP/SGyzaA2k6VIkhSvhPn6wmn+jXPRvhkwFHQldazDI 9zQF2hk0TFXzi78kBLgGwcMd7hvEnu+Zqh8kQjDMFu5qd56K2ygygrrP062Dl/TmyCpk VcXmzFXIaKJ2nBqIm8Q40/pUVyze7tZH1cY9k2RfdYh1g3aCFuqsvrDn4qHdWcnBM/pw ctaw== X-Gm-Message-State: AOJu0YxYcNmJeWq3Vju7Y0M22dm8ew+qQAhfMIcxcopop2lnZe005vJp NlLBI8tZbGM5fvfHFOyn8L0IbKSHNn27RE+jns3kkFGHS9dBW0J6v/qeVGe2p3K95H0= X-Gm-Gg: ATEYQzwTFgkEV7CJ8Jf2tjXOiuHiGblQ6gkFKkSt/OH1uAsBi/nPKn2tubWMqMCIJVz tY1IYV6FNI9OG9U7Z3IKrEZQkluSEm6qlMV2cFEa/DfNAAuux3/2FNsdVX714o0T4Uwpc/XqwmH QEDfp3pgygdf0gy6mJBE/L8YXVEN9mXX9Ail/hchGS3lOfrPFrUhsgKer8lQkdZO7MKuCuXdjzn Rehkh3DxxX9/wV1oAoKXPSl+o5PFt6k0BVgMnRJKT4106eFFUEjdPHTwnjcgA7rx4zDH4uXRoU3 8k4tTWt5VkmyagwvU5s7N8k1e890VmMmLQO6MHtCcghX4p19/6+AJO6ryK6HDhjH3n3vkQAL3KX MoufSdGB0+gGBGt96J65FKV32e3JBWIueWZBELme6ccU9+RR+KArMjbE078atZ9TVrqrq/9lsKB Wv2Ib0E3cvzbvHb+eoE5lVkfHNNrqO/nmZ+i3TQvG5ePoR1D3B7lV3CpqRD0iUy1y94RqdxDdCp Hdv3pdSXg== X-Received: by 2002:a05:6830:3591:b0:7d7:4c90:ddce with SMTP id 46e09a7af769-7d7bb6c99b9mr470879a34.7.1773689857004; Mon, 16 Mar 2026 12:37:37 -0700 (PDT) Received: from [192.168.1.150] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id 46e09a7af769-7d76ae39b39sm13970767a34.15.2026.03.16.12.37.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 16 Mar 2026 12:37:36 -0700 (PDT) Message-ID: <1f79957a-5b23-4bbd-af8d-9d1c86791645@kernel.dk> Date: Mon, 16 Mar 2026 13:37:35 -0600 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] io_uring: cast id to u64 before shifting in io_allocate_rbuf_ring() To: Anas Iqbal , Pavel Begunkov Cc: io-uring@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260316150636.2123-1-mohd.abd.6602@gmail.com> Content-Language: en-US From: Jens Axboe In-Reply-To: <20260316150636.2123-1-mohd.abd.6602@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/16/26 9:06 AM, Anas Iqbal wrote: > Smatch warns: > io_uring/zcrx.c:393 io_allocate_rbuf_ring() warn: should 'id << 16' be a 64 bit type? > > The expression 'id << IORING_OFF_PBUF_SHIFT' is evaluated using 32-bit > arithmetic because id is a u32. This may overflow before being promoted > to the 64-bit mmap_offset. > > Cast id to u64 before shifting to ensure the shift is performed in > 64-bit arithmetic. I'd be impressed if 'id' could be large enough to cause this to overflow. AFAICT, you'd need more than 64K interface queues registered to hit this. So I think this should be reframed as a cleanup, to appease smatch. I'll defer to Pavel on that one. -- Jens Axboe