From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 2502F13D532 for ; Wed, 22 May 2024 13:15:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716383726; cv=none; b=RvY0tSeom1zyIMEHq3lKH72gfQLgsY2Yt7vQNpltaDJ48UHxSXQGeEYMYImGOvoxRqzIbeYauxDDRmYPMhPtz4yRGRbLk24b9fAbGPy2F4d2AIpzxXO3PHF/goX82QQDyM2gOV/kkS+n+B9pObzbhTgslOhUfq70N3mVSHazdVY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716383726; c=relaxed/simple; bh=uLnhViPu3gKMuUJBRCARdTqjTRtx+rKZw7tS8gTAar0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AarhJ4H/jIUogHlk8VQ7buSN3PekqQ9S0H/xPpwqi+nLjeKhnzVYDe7+7Emrx2DldLvbwjAqw1cj6k1lsLX67/3aR1SMBjyQsLnixzzMt3hEsCIbs76AZrLQa6RQlD8bbbLrk/KqvGjiopNxQdeOWsBX8/YQksjzxoEUAUwABOc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=iVoG65Ty; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="iVoG65Ty" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1716383724; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=gG/nMjAoz9LDk2w+nQo6Krx4ydggfzKbEuvqJwzneL4=; b=iVoG65Ty/MdN4/L6k49H4mNq77Gp8hCf+as5TZEPh3sZH77D/ytRTJyjTZRfgY63SmKvyN JgzOSWn7AvL3ADlJDmQN1bTrtlZUYdqDL9sYPDIpmiveUeG88zHGA4d/VHEAksVLi/5G6S pZSYJmB/Zl2VoOQqHHylPb1pLfH70X0= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-226-GfQF3paeNZylWi2WTvZvXw-1; Wed, 22 May 2024 09:15:18 -0400 X-MC-Unique: GfQF3paeNZylWi2WTvZvXw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 388D638000AB; Wed, 22 May 2024 13:15:18 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.225.153]) by smtp.corp.redhat.com (Postfix) with SMTP id 8CA2C2026D33; Wed, 22 May 2024 13:15:16 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Wed, 22 May 2024 15:13:51 +0200 (CEST) Date: Wed, 22 May 2024 15:13:49 +0200 From: Oleg Nesterov To: kernel test robot Cc: oe-kbuild-all@lists.linux.dev, linux-kernel@vger.kernel.org, Ingo Molnar , Thomas Gleixner , Phil Auld Subject: Re: kernel/sched/isolation.c:143 housekeeping_setup() warn: always true condition '(first_cpu >= 0) => (0-u32max >= 0)' Message-ID: <20240522131349.GA3582@redhat.com> References: <202404300915.WNvfwBz3-lkp@intel.com> Precedence: bulk X-Mailing-List: oe-kbuild-all@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: User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.4 On 05/02, Oleg Nesterov wrote: > > I am on PTO till May 9 without my working laptop, can't even read the source code. > I'll return to this when I'm back. CONFIG_SMP=n I guess. Sorry for late reply. So smatch dislikes the first_cpu >= setup_max_cpus check because setup_max_cpus is 0 without CONFIG_SMP. I don't think it makes sense to try to avoid this warning, isolation.c should not be compiled without CONFIG_SMP=y, but we have config CPU_ISOLATION bool "CPU isolation" depends on SMP || COMPILE_TEST and this randconfig selects COMPILE_TEST. Oleg. > On 04/30, kernel test robot wrote: > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master > > head: 98369dccd2f8e16bf4c6621053af7aa4821dcf8e > > commit: 257bf89d84121280904800acd25cc2c444c717ae sched/isolation: Fix boot crash when maxcpus < first housekeeping CPU > > date: 2 days ago > > config: xtensa-randconfig-r081-20240429 (https://download.01.org/0day-ci/archive/20240430/202404300915.WNvfwBz3-lkp@intel.com/config) > > compiler: xtensa-linux-gcc (GCC) 13.2.0 > > > > 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/202404300915.WNvfwBz3-lkp@intel.com/ > > > > New smatch warnings: > > kernel/sched/isolation.c:143 housekeeping_setup() warn: always true condition '(first_cpu >= 0) => (0-u32max >= 0)' > > > > Old smatch warnings: > > arch/xtensa/include/asm/thread_info.h:97 current_thread_info() warn: inconsistent indenting > > > > vim +143 kernel/sched/isolation.c > > > > 117 > > 118 static int __init housekeeping_setup(char *str, unsigned long flags) > > 119 { > > 120 cpumask_var_t non_housekeeping_mask, housekeeping_staging; > > 121 unsigned int first_cpu; > > 122 int err = 0; > > 123 > > 124 if ((flags & HK_FLAG_TICK) && !(housekeeping.flags & HK_FLAG_TICK)) { > > 125 if (!IS_ENABLED(CONFIG_NO_HZ_FULL)) { > > 126 pr_warn("Housekeeping: nohz unsupported." > > 127 " Build with CONFIG_NO_HZ_FULL\n"); > > 128 return 0; > > 129 } > > 130 } > > 131 > > 132 alloc_bootmem_cpumask_var(&non_housekeeping_mask); > > 133 if (cpulist_parse(str, non_housekeeping_mask) < 0) { > > 134 pr_warn("Housekeeping: nohz_full= or isolcpus= incorrect CPU range\n"); > > 135 goto free_non_housekeeping_mask; > > 136 } > > 137 > > 138 alloc_bootmem_cpumask_var(&housekeeping_staging); > > 139 cpumask_andnot(housekeeping_staging, > > 140 cpu_possible_mask, non_housekeeping_mask); > > 141 > > 142 first_cpu = cpumask_first_and(cpu_present_mask, housekeeping_staging); > > > 143 if (first_cpu >= nr_cpu_ids || first_cpu >= setup_max_cpus) { > > 144 __cpumask_set_cpu(smp_processor_id(), housekeeping_staging); > > 145 __cpumask_clear_cpu(smp_processor_id(), non_housekeeping_mask); > > 146 if (!housekeeping.flags) { > > 147 pr_warn("Housekeeping: must include one present CPU, " > > 148 "using boot CPU:%d\n", smp_processor_id()); > > 149 } > > 150 } > > 151 > > 152 if (cpumask_empty(non_housekeeping_mask)) > > 153 goto free_housekeeping_staging; > > 154 > > 155 if (!housekeeping.flags) { > > 156 /* First setup call ("nohz_full=" or "isolcpus=") */ > > 157 enum hk_type type; > > 158 > > 159 for_each_set_bit(type, &flags, HK_TYPE_MAX) > > 160 housekeeping_setup_type(type, housekeeping_staging); > > 161 } else { > > 162 /* Second setup call ("nohz_full=" after "isolcpus=" or the reverse) */ > > 163 enum hk_type type; > > 164 unsigned long iter_flags = flags & housekeeping.flags; > > 165 > > 166 for_each_set_bit(type, &iter_flags, HK_TYPE_MAX) { > > 167 if (!cpumask_equal(housekeeping_staging, > > 168 housekeeping.cpumasks[type])) { > > 169 pr_warn("Housekeeping: nohz_full= must match isolcpus=\n"); > > 170 goto free_housekeeping_staging; > > 171 } > > 172 } > > 173 > > 174 iter_flags = flags & ~housekeeping.flags; > > 175 > > 176 for_each_set_bit(type, &iter_flags, HK_TYPE_MAX) > > 177 housekeeping_setup_type(type, housekeeping_staging); > > 178 } > > 179 > > 180 if ((flags & HK_FLAG_TICK) && !(housekeeping.flags & HK_FLAG_TICK)) > > 181 tick_nohz_full_setup(non_housekeeping_mask); > > 182 > > 183 housekeeping.flags |= flags; > > 184 err = 1; > > 185 > > 186 free_housekeeping_staging: > > 187 free_bootmem_cpumask_var(housekeeping_staging); > > 188 free_non_housekeeping_mask: > > 189 free_bootmem_cpumask_var(non_housekeeping_mask); > > 190 > > 191 return err; > > 192 } > > 193 > > > > -- > > 0-DAY CI Kernel Test Service > > https://github.com/intel/lkp-tests/wiki > > >