From patchwork Mon Aug 12 06:20:17 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jinjie Ruan X-Patchwork-Id: 13760162 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 040B0C52D7C for ; Mon, 12 Aug 2024 06:14:42 +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: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:In-Reply-To:References:List-Owner; bh=nwPsOqkLzGqqitAahJSR2GXRTwKCh6Gf58T+EpZtLiA=; b=J7KWxDdeh6o804Jd6/65OK9vRt 29E6bIM/eldmHBB+kxR53bVelCc2JKEC/aQL3OYi8bVO0G16PWen2nUghXdQkYxrlZl+BhJsE8m1H fQnZ2okRFGJjLPEbuOSHIfHDiPh2J96iSzvQdQH9MLXC07k+FZbncKkjrUDFaMVwgITHBEen/LegL rpglVdaDo+AaIahh7VN6/qYiJFeyWl166IaCZbpGylL2r6VFnRutAw7LBhiux01ay+DcuwWuF6tIj Btt2xE82nkScbMfAyqViBShYvjzvjFVPxfTB4KkgzTjwpXtx3N+ax0NEZxCf0Zfb3zzGeWA7SXzBW J9XDq78A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sdOK7-0000000Gytn-0e6V; Mon, 12 Aug 2024 06:14:31 +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 1sdOJU-0000000Gyi9-2Sww; Mon, 12 Aug 2024 06:13:54 +0000 Received: from mail.maildlp.com (unknown [172.19.88.105]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4Wj3xb4K1vzQpcx; Mon, 12 Aug 2024 14:09:07 +0800 (CST) Received: from kwepemi100008.china.huawei.com (unknown [7.221.188.57]) by mail.maildlp.com (Postfix) with ESMTPS id 9213E1402E2; Mon, 12 Aug 2024 14:13:39 +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; Mon, 12 Aug 2024 14:13:38 +0800 From: Jinjie Ruan To: , , , , , , , , , , , , CC: Subject: [PATCH -next v2] crash: Fix riscv64 crash memory reserve dead loop Date: Mon, 12 Aug 2024 14:20:17 +0800 Message-ID: <20240812062017.2674441-1-ruanjinjie@huawei.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Originating-IP: [10.90.53.73] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) 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-20240811_231352_915292_9C1BDEED X-CRM114-Status: GOOD ( 12.03 ) 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 RISCV64 Qemu machine with 512MB memory, cmdline "crashkernel=500M,high" will cause system stall as below: Zone ranges: DMA32 [mem 0x0000000080000000-0x000000009fffffff] Normal empty Movable zone start for each node Early memory node ranges node 0: [mem 0x0000000080000000-0x000000008005ffff] node 0: [mem 0x0000000080060000-0x000000009fffffff] Initmem setup node 0 [mem 0x0000000080000000-0x000000009fffffff] (stall here) commit 5d99cadf1568 ("crash: fix x86_32 crash memory reserve dead loop bug") fix this on 32-bit architecture. However, the problem is not completely solved. If `CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX` on 64-bit architecture, for example, when system memory is equal to CRASH_ADDR_LOW_MAX on RISCV64, the following infinite loop will also occur: -> reserve_crashkernel_generic() and high is true -> alloc at [CRASH_ADDR_LOW_MAX, CRASH_ADDR_HIGH_MAX] fail -> alloc at [0, CRASH_ADDR_LOW_MAX] fail and repeatedly (because CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX). As Catalin suggested, do not remove the ",high" reservation fallback to ",low" logic which will change arm64's kdump behavior, but fix it by skipping the above situation similar to commit d2f32f23190b ("crash: fix x86_32 crash memory reserve dead loop"). After this patch, it print: cannot allocate crashkernel (size:0x1f400000) Signed-off-by: Jinjie Ruan Suggested-by: Catalin Marinas Reviewed-by: Catalin Marinas Acked-by: Baoquan He --- v2: - Fix it in another way suggested by Catalin. - Add Suggested-by. --- 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 5387269114f6..aae4a9e998d1 100644 --- a/kernel/crash_reserve.c +++ b/kernel/crash_reserve.c @@ -427,7 +427,8 @@ void __init reserve_crashkernel_generic(char *cmdline, if (high && search_end == CRASH_ADDR_HIGH_MAX) { search_end = CRASH_ADDR_LOW_MAX; search_base = 0; - goto retry; + if (search_end != CRASH_ADDR_HIGH_MAX) + goto retry; } pr_warn("cannot allocate crashkernel (size:0x%llx)\n", crash_size);