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 E41ED23F417; Fri, 9 Jan 2026 12:28:19 +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=1767961700; cv=none; b=b42cbiMQqZ0Uu1iVp7jEM5tQXfSeZ2af5flvL7pQVZ2yKeepsTeLg2HkRDgAOntl7FpoXjTAxAwIfKqfP0pqc/znMDlpNO3AsEDxmQ3ZYP12J6En7c9JtYOS3dGCg79ASfD13iA78C5CsCVbD9Ncj08u/yglSM4BG0BhsJX2SV0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767961700; c=relaxed/simple; bh=Aa3cYXA+8jsVU/9YQneXAtrbSNCzaz1BE8bEV/Cqjk8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZJHQpdq/ieuxKXIMpBYdHTv6s/l31F3KynTov1qNUGYOO8qdz66wE8oUd+K1t9y1NiUeYYXbh0xMm0qIXSncesJ0EVq7TNcaSqYKkKSRbHkifMyBUPurA1u50YKN7Us/H3nYev6hlHYTiOLlmwjohXerouW8qZdwmxVPeNdCiF8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=O4BALS87; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="O4BALS87" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7079EC4CEF1; Fri, 9 Jan 2026 12:28:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767961699; bh=Aa3cYXA+8jsVU/9YQneXAtrbSNCzaz1BE8bEV/Cqjk8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=O4BALS87pLvd3cW/aak+kTk/HKGnNXEmiwPU+KJrAd8PL1/E5Ya+/uPqRtMnLs3hD qTyIB/l6Xc5hNDTJSvwavqiDt16sOx+T7+eLtacDkIYmAn3NwupfCai7ehUEc+FJyx YVvcpWfoOt4mZETG9g5YnRC0xbZi+87/IgZEba0Q= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alexander Egorenkov , Mete Durlu , Heiko Carstens , Sasha Levin Subject: [PATCH 6.1 063/634] s390/smp: Fix fallback CPU detection Date: Fri, 9 Jan 2026 12:35:41 +0100 Message-ID: <20260109112119.817365938@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260109112117.407257400@linuxfoundation.org> References: <20260109112117.407257400@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Heiko Carstens [ Upstream commit 07a75d08cfa1b883a6e1256666e5f0617ee99231 ] In case SCLP CPU detection does not work a fallback mechanism using SIGP is in place. Since a cleanup this does not work correctly anymore: new CPUs are only considered if their type matches the boot CPU. Before the cleanup the information if a CPU type should be considered was also part of a structure generated by the fallback mechanism and indicated that a CPU type should not be considered when adding CPUs. Since the rework a global SCLP state is used instead. If the global SCLP state indicates that the CPU type should be considered and the fallback mechanism is used, there may be a mismatch with CPU types if CPUs are added. This can lead to a system with only a single CPU even tough there are many more CPUs. Address this by simply copying the boot cpu type into the generated data structure from the fallback mechanism. Reported-by: Alexander Egorenkov Fixes: d08d94306e90 ("s390/smp: cleanup core vs. cpu in the SCLP interface") Reviewed-by: Mete Durlu Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin --- arch/s390/kernel/smp.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 436dbf4d743d8..8346cb75643ca 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -758,6 +758,7 @@ static void __ref smp_get_core_info(struct sclp_core_info *info, int early) continue; info->core[info->configured].core_id = address >> smp_cpu_mt_shift; + info->core[info->configured].type = boot_core_type; info->configured++; } info->combined = info->configured; -- 2.51.0