From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 A7C084AEBD3 for ; Mon, 28 Sep 2026 11:42:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790595756; cv=none; b=gA/99NGBoCupNwuLeVhNN5YC0i/68+KrYA/FTYYGlRty4ABpqBZsZbEI+5yRrhOSOLDHvseGrYokdL89GDuyo3zcryRLzTzQBoIfBXOmdgG6IE47b4QmqpAVNkRCCz4+Xge+342c30DnLyedSsT9PPQ3kPCrezLSSYvbUVdYmJ4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790595756; c=relaxed/simple; bh=lGvaI1yOS9HzYYl/sLjgqmwdkYA6UjnAuz1n/O2UkZg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=nee/hReHMgIfxQxj76RObpWTSIu8p05aHtEdJujtdDcCv2Uzg023l4C844uPSSZLne80KQ1OB9mgNu9o5sMzEWB8dD0i12/KW7Dd03/ZX3ppxTciPw5YC4IJMRl2h0+Q7jSl1jBZbCUHmNPw2A2QvrhkQRWEg7Q8TXw3F/UZJCA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ru89tl2Q; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ru89tl2Q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 731591F00893; Mon, 28 Sep 2026 11:42:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790595755; bh=nyi2h4pBa6aCzJLG0YIuvLzyd1MNYWiHYXFs0BMepts=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=Ru89tl2QGLKPM68mggJL9czQCpnCrSr+isKp3atpqRRcql6+o7opzpvFWSzcIDXPl JGByY9q8sjUYq9vWIS01Jc7lEgCJbIWajWkTl2390FTR+0mYhFnu5WaDSK3VtWUFHx 9ho3EtniK5Gr/rRTNr0sooak9eJVV2rZ7/FzOkRT5auf/komgOjVdu5J4RFbAmh90D hw52plXyg9wNAt1IAWmWHFHoRrJYTU/6+hNz1W/jNPQUdhtUbLd3NpLC93/BbZaY/p TdtfnTpxgtNJWEUBC0p8b/zzqhisqyNT0eX2sMtoaaVePMxL20iqy6hGuGUjBu0NEg khg8Rm8cAnosw== Message-ID: <4a57b255-cb38-4e8e-908b-d32e55a1a326@kernel.org> Date: Mon, 28 Sep 2026 13:42:29 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] vmcoreinfo: export SECTION_HAS_MEM_MAP To: Dave Young , Andrew Morton , Baoquan He , David Carlier Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, kexec@lists.infradead.org References: <20260928-section_has_mem_map-v1-1-4129f6ba2838@kernel.org> <9c47dad9-2716-4ae0-b6e2-9e6b5c718859@linux.dev> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/28/26 12:23, Dave Young wrote: > On 9/28/26 4:48 PM, David Hildenbrand (Arm) wrote: >> The crash tool currently hardcodes SECTION_HAS_MEM_MAP, and makedumpfile >> needs similar information (although still relying on >> SECTION_MARKED_PRESENT, it should switch to SECTION_HAS_MEM_MAP). >> >> Let's just export the value instead, so tools that work on vmcoreinfo >> will not have to guess. >> >> Signed-off-by: David Hildenbrand (Arm) >> --- >> Result of the discussion in reply to "[PATCH v2 00/13] mm/sparse: remove >> SECTION_MARKED_PRESENT and further cleanups" [1] >> >> This patch can go in independently. It would be preferable if both >> go into the same kernel release ;) >> >> [1] https://lore.kernel.org/r/20260921-b4-sparsemem_cleanups-v2-0-54d81d65e125@kernel.org >> --- >> kernel/vmcore_info.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/kernel/vmcore_info.c b/kernel/vmcore_info.c >> index 5a417f8a922a..7833a36064a8 100644 >> --- a/kernel/vmcore_info.c >> +++ b/kernel/vmcore_info.c >> @@ -182,6 +182,7 @@ static int __init crash_save_vmcoreinfo_init(void) >> VMCOREINFO_STRUCT_SIZE(mem_section); >> VMCOREINFO_OFFSET(mem_section, section_mem_map); >> VMCOREINFO_NUMBER(SECTION_SIZE_BITS); >> + VMCOREINFO_NUMBER(SECTION_HAS_MEM_MAP); >> VMCOREINFO_NUMBER(MAX_PHYSMEM_BITS); >> #endif >> VMCOREINFO_STRUCT_SIZE(page); > > Current crash code looks below: > #define SECTION_MARKED_PRESENT (1UL<<0) > #define SECTION_HAS_MEM_MAP (1UL<<1) > #define SECTION_IS_ONLINE (1UL<<2) > #define SECTION_IS_EARLY (1UL<<3) > #define SECTION_TAINT_ZONE_DEVICE (1UL<<4) > #define SECTION_MAP_LAST_BIT (1UL<<5) > #define SECTION_MAP_MASK (~(SECTION_MAP_LAST_BIT-1)) > > > And it does not match the kernel for below chunk with ifdef > #ifdef CONFIG_ZONE_DEVICE > SECTION_TAINT_ZONE_DEVICE_BIT, > #endif > #ifdef CONFIG_SPARSEMEM_VMEMMAP_PREINIT > SECTION_IS_VMEMMAP_PREINIT_BIT, > #endif > > The last bit could be wrong in crash. So all numbers should be exported in vmcoreinfo. > > Thoughts? You know the crash code best, so likely ... it's time one of the crash people takes over this patch? -- Cheers, David