From patchwork Thu Jul 18 03:54:43 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jinjie Ruan X-Patchwork-Id: 13735995 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7E2B4C3DA49 for ; Thu, 18 Jul 2024 03:51:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=zNrRpN0TmI+g0ejZsweX4m8LfyfLvMfZxh/eb4TvEO0=; b=OtLnalJ7JwzFFXOTt7mH5iyzKm k58es8NfzbUyo9bElZR8FvpXOsfybzlm6ZQVAZbxsvvNodqAF1SCwMQCJ8e/iNunWleLifjtlHXSF Dav4jWhuTisZoQVuI9RkFDMnwWFC8UvR8Y3bcKR45VvMzXPB3z8QdHF6Qflx8FeeOUppcAXHWT3EW VdTNf8ybMB1Gu1Bey4U7RTGGlxCbgZPPz8Nl5cfJuXUe2okPUeX8FhtzQPQh5uO2uyzSlmCNc3VVG hYefKwGf0fPF3f4q9TEkaLEhL4x7PCv90HBEJZhooDwAUWM1nI48Bh0s8TeMSNfxNp8FzKv6UqhNZ Fc+TwHFQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sUIAp-0000000Ffpx-13yI; Thu, 18 Jul 2024 03:51:19 +0000 Received: from szxga03-in.huawei.com ([45.249.212.189]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sUIA9-0000000FfPy-03yD; Thu, 18 Jul 2024 03:50:38 +0000 Received: from mail.maildlp.com (unknown [172.19.162.254]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4WPdyZ6ZSXzQm2G; Thu, 18 Jul 2024 11:46:30 +0800 (CST) Received: from kwepemi100008.china.huawei.com (unknown [7.221.188.57]) by mail.maildlp.com (Postfix) with ESMTPS id 3489718010A; Thu, 18 Jul 2024 11:50:20 +0800 (CST) Received: from huawei.com (10.90.53.73) by kwepemi100008.china.huawei.com (7.221.188.57) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Thu, 18 Jul 2024 11:50:04 +0800 From: Jinjie Ruan To: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , CC: Subject: [PATCH v3 2/3] crash: Fix x86_32 crash memory reserve dead loop bug at high Date: Thu, 18 Jul 2024 11:54:43 +0800 Message-ID: <20240718035444.2977105-3-ruanjinjie@huawei.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240718035444.2977105-1-ruanjinjie@huawei.com> References: <20240718035444.2977105-1-ruanjinjie@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.90.53.73] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemi100008.china.huawei.com (7.221.188.57) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240717_205037_456495_B81D881E X-CRM114-Status: GOOD ( 10.57 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On x86_32 Qemu machine with 1GB memory, the cmdline "crashkernel=512M" will also cause system stall as below: ACPI: Reserving FACP table memory at [mem 0x3ffe18b8-0x3ffe192b] ACPI: Reserving DSDT table memory at [mem 0x3ffe0040-0x3ffe18b7] ACPI: Reserving FACS table memory at [mem 0x3ffe0000-0x3ffe003f] ACPI: Reserving APIC table memory at [mem 0x3ffe192c-0x3ffe19bb] ACPI: Reserving HPET table memory at [mem 0x3ffe19bc-0x3ffe19f3] ACPI: Reserving WAET table memory at [mem 0x3ffe19f4-0x3ffe1a1b] 143MB HIGHMEM available. 879MB LOWMEM available. mapped low ram: 0 - 36ffe000 low ram: 0 - 36ffe000 (stall here) The reason is that the CRASH_ADDR_LOW_MAX is equal to CRASH_ADDR_HIGH_MAX on x86_32, the first "low" crash kernel memory reservation for 512M fails, then it go into the "retry" loop and never came out as below (consider CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX = 512M): -> reserve_crashkernel_generic() and high is false -> alloc at [0, 0x20000000] fail -> alloc at [0x20000000, 0x20000000] fail and repeatedly (because CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX). Fix it by skipping meaningless calls of memblock_phys_alloc_range() with `start = end` After this patch, the retry dead loop is avoided and print below info: cannot allocate crashkernel (size:0x20000000) And apply generic crashkernel reservation to 32bit system will be ready. Fixes: 9c08a2a139fe ("x86: kdump: use generic interface to simplify crashkernel reservation code") Signed-off-by: Jinjie Ruan Signed-off-by: Baoquan He Tested-by: Jinjie Ruan --- v3: - Fix it as Baoquan suggested. - Update the commit message. --- kernel/crash_reserve.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/crash_reserve.c b/kernel/crash_reserve.c index c5213f123e19..dacc268429e2 100644 --- a/kernel/crash_reserve.c +++ b/kernel/crash_reserve.c @@ -414,7 +414,8 @@ void __init reserve_crashkernel_generic(char *cmdline, search_end = CRASH_ADDR_HIGH_MAX; search_base = CRASH_ADDR_LOW_MAX; crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; - goto retry; + if (search_base != search_end) + goto retry; } /*