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 B801121C17D; Mon, 1 Dec 2025 19:10:56 +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=1764616256; cv=none; b=hjU3l8YA1EQHeK8R6mqE3x6cDvkLfH8V7Ge2gYR5IPYJmxP20NivCkJNFHKD8OxZjDF9+RXofgcDbjjUZ7SrX2wLAUNf1vFMTGeLqz+0KeZA5i61Y9u2vuVWYgt1NMxsvbkH21yU33rTXSc1cw0emVyz9c7fVTOW10p6QflMTpw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764616256; c=relaxed/simple; bh=3uLftGmXOJVyk3JM6exrsoORdteRFaEjZfuhX0PK5Sc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=hxTH2rJIA3gdailvYFk8hquo8Z3VzZlRhlyOcaNvraOB2Cpu54bZ1KBLZyd+rRxesMm/d8x0KTlopLwvu9Q3O4zR3sxvfSg7tFDLpmeu2MpVVcCb86Z/JV9ZMtQ9VPoKCRhVLwd0lirjY4td9hnSAtIl0zNnyV6EpdCep01IsLY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pPBV4eFB; 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="pPBV4eFB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 01AA3C4CEF1; Mon, 1 Dec 2025 19:10:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764616256; bh=3uLftGmXOJVyk3JM6exrsoORdteRFaEjZfuhX0PK5Sc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pPBV4eFBZt3lu0SaKfidmAoDBiMG70orPFB2cKx/G0UQ9ROBSvdLAs7Sr/LucVAJe xq6i9jQTqmdHtOETnFDMPgDlUoZ/qV+eL0ZuxdJTjDotoH5N3B60P7Dhwoc4ltGQS3 kzaqGZNWVOTwmTVl4sgpcK7J2s26CGYDQFKP15nbb5BHx3I0ynzex9RdZX8p3T0ICd nyQGHmAWRIJpauTDiZFo0mfsbcLRyqZ5AyhU6MJKnZy5N4oS08M1ZgjPuZABT9cjto JqLHj06CEzlP91WCSn0nxXx2z3h8W8VEwCMcDcjKO88ASOm68K3FeY/fZfOYcHA1wG Cg1lLyO9zFs8A== Date: Mon, 1 Dec 2025 12:10:52 -0700 From: Nathan Chancellor To: Seven Lee , Jaroslav Kysela , Mark Brown Cc: llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev, kernel test robot Subject: Re: [linux-next:master 11929/12398] sound/soc/codecs/nau8325.c:430:13: warning: variable 'n2_max' is uninitialized when used here Message-ID: <20251201191052.GA2727778@ax162> References: <202511271353.g6GYVUt6-lkp@intel.com> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202511271353.g6GYVUt6-lkp@intel.com> On Thu, Nov 27, 2025 at 01:50:44PM +0800, kernel test robot wrote: > Hi Jaroslav, > > First bad commit (maybe != root cause): Indeed, this appears to be a problem from commit c0a3873b9938 ("ASoC: nau8325: new driver"), it was simply not visible before the driver was actually hooked into the build system. > tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > head: ef68bf704646690aba5e81c2f7be8d6ef13d7ad8 > commit: cd41d3420ef658b2ca902d7677536ec8e25b610a [11929/12398] ASoC: nau8325: add missing build config > config: loongarch-allmodconfig (https://download.01.org/0day-ci/archive/20251127/202511271353.g6GYVUt6-lkp@intel.com/config) > compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90) > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251127/202511271353.g6GYVUt6-lkp@intel.com/reproduce) > > If you fix the issue in a separate patch/commit (i.e. not just a new version of > the same patch/commit), kindly add following tags > | Reported-by: kernel test robot > | Closes: https://lore.kernel.org/oe-kbuild-all/202511271353.g6GYVUt6-lkp@intel.com/ > > All warnings (new ones prefixed by >>): > > >> sound/soc/codecs/nau8325.c:430:13: warning: variable 'n2_max' is uninitialized when used here [-Wuninitialized] > 430 | *n2_sel = n2_max; > | ^~~~~~ > sound/soc/codecs/nau8325.c:389:52: note: initialize the variable 'n2_max' to silence this warning > 389 | int i, j, mclk, mclk_max, ratio, ratio_sel, n2_max; > | ^ > | = 0 > >> sound/soc/codecs/nau8325.c:431:11: warning: variable 'ratio_sel' is uninitialized when used here [-Wuninitialized] > 431 | ratio = ratio_sel; > | ^~~~~~~~~ > sound/soc/codecs/nau8325.c:389:44: note: initialize the variable 'ratio_sel' to silence this warning > 389 | int i, j, mclk, mclk_max, ratio, ratio_sel, n2_max; > | ^ > | = 0 > 2 warnings generated. This warning seems legitimate even though it seems like there is no harm at runtime? > vim +/n2_max +430 sound/soc/codecs/nau8325.c > > c0a3873b9938bf Seven Lee 2024-03-27 384 > c0a3873b9938bf Seven Lee 2024-03-27 385 static int nau8325_clksrc_choose(struct nau8325 *nau8325, > c0a3873b9938bf Seven Lee 2024-03-27 386 const struct nau8325_srate_attr **srate_table, > c0a3873b9938bf Seven Lee 2024-03-27 387 int *n1_sel, int *mult_sel, int *n2_sel) > c0a3873b9938bf Seven Lee 2024-03-27 388 { > c0a3873b9938bf Seven Lee 2024-03-27 389 int i, j, mclk, mclk_max, ratio, ratio_sel, n2_max; > c0a3873b9938bf Seven Lee 2024-03-27 390 > c0a3873b9938bf Seven Lee 2024-03-27 391 if (!nau8325->mclk || !nau8325->fs) > c0a3873b9938bf Seven Lee 2024-03-27 392 goto proc_err; > c0a3873b9938bf Seven Lee 2024-03-27 393 > c0a3873b9938bf Seven Lee 2024-03-27 394 /* select sampling rate and MCLK_SRC */ > c0a3873b9938bf Seven Lee 2024-03-27 395 *srate_table = target_srate_attribute(nau8325->fs); > c0a3873b9938bf Seven Lee 2024-03-27 396 if (!*srate_table) > c0a3873b9938bf Seven Lee 2024-03-27 397 goto proc_err; > c0a3873b9938bf Seven Lee 2024-03-27 398 > c0a3873b9938bf Seven Lee 2024-03-27 399 /* First check clock from MCLK directly, decide N2 for MCLK_SRC. > c0a3873b9938bf Seven Lee 2024-03-27 400 * If not good, consider 1/N1 and Multiplier. > c0a3873b9938bf Seven Lee 2024-03-27 401 */ > c0a3873b9938bf Seven Lee 2024-03-27 402 ratio = nau8325_clksrc_n2(nau8325, *srate_table, nau8325->mclk, n2_sel); > c0a3873b9938bf Seven Lee 2024-03-27 403 if (ratio != NAU8325_MCLK_FS_RATIO_NUM) { > c0a3873b9938bf Seven Lee 2024-03-27 404 *n1_sel = 0; > c0a3873b9938bf Seven Lee 2024-03-27 405 *mult_sel = CLK_PROC_BYPASS; > c0a3873b9938bf Seven Lee 2024-03-27 406 *n2_sel = MCLK_SRC; > c0a3873b9938bf Seven Lee 2024-03-27 407 goto proc_done; > c0a3873b9938bf Seven Lee 2024-03-27 408 } > c0a3873b9938bf Seven Lee 2024-03-27 409 > c0a3873b9938bf Seven Lee 2024-03-27 410 /* Get MCLK_SRC through 1/N, Multiplier, and then 1/N2. */ > c0a3873b9938bf Seven Lee 2024-03-27 411 mclk_max = 0; > c0a3873b9938bf Seven Lee 2024-03-27 412 for (i = 0; i < ARRAY_SIZE(mclk_n1_div); i++) { > c0a3873b9938bf Seven Lee 2024-03-27 413 for (j = 0; j < ARRAY_SIZE(mclk_n3_mult); j++) { > c0a3873b9938bf Seven Lee 2024-03-27 414 mclk = nau8325->mclk << mclk_n3_mult[j].param; > c0a3873b9938bf Seven Lee 2024-03-27 415 mclk = mclk / mclk_n1_div[i].param; > c0a3873b9938bf Seven Lee 2024-03-27 416 ratio = nau8325_clksrc_n2(nau8325, > c0a3873b9938bf Seven Lee 2024-03-27 417 *srate_table, mclk, n2_sel); > c0a3873b9938bf Seven Lee 2024-03-27 418 if (ratio != NAU8325_MCLK_FS_RATIO_NUM && > c0a3873b9938bf Seven Lee 2024-03-27 419 (mclk_max < mclk || i > *n1_sel)) { > c0a3873b9938bf Seven Lee 2024-03-27 420 mclk_max = mclk; > c0a3873b9938bf Seven Lee 2024-03-27 421 n2_max = *n2_sel; > c0a3873b9938bf Seven Lee 2024-03-27 422 *n1_sel = i; > c0a3873b9938bf Seven Lee 2024-03-27 423 *mult_sel = j; > c0a3873b9938bf Seven Lee 2024-03-27 424 ratio_sel = ratio; > c0a3873b9938bf Seven Lee 2024-03-27 425 goto proc_done; n2_max and ratio_sel are only assigned in this if block, which ends in an unconditional jump to proc_done... > c0a3873b9938bf Seven Lee 2024-03-27 426 } > c0a3873b9938bf Seven Lee 2024-03-27 427 } > c0a3873b9938bf Seven Lee 2024-03-27 428 } > c0a3873b9938bf Seven Lee 2024-03-27 429 if (mclk_max) { > c0a3873b9938bf Seven Lee 2024-03-27 @430 *n2_sel = n2_max; > c0a3873b9938bf Seven Lee 2024-03-27 @431 ratio = ratio_sel; > c0a3873b9938bf Seven Lee 2024-03-27 432 goto proc_done; > c0a3873b9938bf Seven Lee 2024-03-27 433 } which will always skip this if block, so if this if statement is taken, these values are genuinely uninitialized. However, as far as I can tell, if the first if statement is not taken, mclk_max will be 0, so it seems like this if statement is never taken and is dead code? At the same time, won't 'mclk_max < mclk' always be true unless mclk itself is 0, so what purpose does mclk_max serve otherwise? Was it intentional that the first if statement ends in a jump to proc_done? It looks like the value of n2_max is never actually used outside of this dead if statement. > c0a3873b9938bf Seven Lee 2024-03-27 435 proc_err: > c0a3873b9938bf Seven Lee 2024-03-27 436 dev_dbg(nau8325->dev, "The MCLK %d is invalid. It can't get MCLK_SRC of 256/400/500 FS (%d)", > c0a3873b9938bf Seven Lee 2024-03-27 437 nau8325->mclk, nau8325->fs); > c0a3873b9938bf Seven Lee 2024-03-27 438 return -EINVAL; > c0a3873b9938bf Seven Lee 2024-03-27 439 proc_done: > c0a3873b9938bf Seven Lee 2024-03-27 440 dev_dbg(nau8325->dev, "nau8325->fs=%d,range=0x%x, %s, (n1,mu,n2,dmu):(%d,%d,%d), MCLK_SRC=%uHz (%d)", > c0a3873b9938bf Seven Lee 2024-03-27 441 nau8325->fs, (*srate_table)->range, > c0a3873b9938bf Seven Lee 2024-03-27 442 (*srate_table)->max ? "MAX" : "MIN", > c0a3873b9938bf Seven Lee 2024-03-27 443 *n1_sel == CLK_PROC_BYPASS ? > c0a3873b9938bf Seven Lee 2024-03-27 444 CLK_PROC_BYPASS : mclk_n1_div[*n1_sel].param, > c0a3873b9938bf Seven Lee 2024-03-27 445 *mult_sel == CLK_PROC_BYPASS ? > c0a3873b9938bf Seven Lee 2024-03-27 446 CLK_PROC_BYPASS : 1 << mclk_n3_mult[*mult_sel].param, > c0a3873b9938bf Seven Lee 2024-03-27 447 1 << mclk_n2_div[*n2_sel].param, > c0a3873b9938bf Seven Lee 2024-03-27 448 (*srate_table)->mclk_src[ratio], > c0a3873b9938bf Seven Lee 2024-03-27 449 (*srate_table)->mclk_src[ratio] / nau8325->fs); > c0a3873b9938bf Seven Lee 2024-03-27 450 > c0a3873b9938bf Seven Lee 2024-03-27 451 return 0; > c0a3873b9938bf Seven Lee 2024-03-27 452 } > c0a3873b9938bf Seven Lee 2024-03-27 453 Cheers, Nathan