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 C7E3C2459E9 for ; Thu, 17 Apr 2025 12:27:16 +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=1744892836; cv=none; b=eoXkNOD+cZoOe4aqPqlHuPxyQcze4QkFrEyeik58J8rpWMvhHA3Nhr68IX9qHINbg/ZeNnGNEMbxt4Y9sdlK3RYaA6HyipZWsl+AkE5ryvyCa5AqfvEBKU8/W2qbVEL2+pfc/wQxt7s9OL3HILfr9SJnn4+QGg1/B5DdEWRsyR4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744892836; c=relaxed/simple; bh=foYOSk+C4jWUa4BNln8QbxDRmDvP7m18xB7ecrYazbU=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=r8VNcQFHtmQXt9DDXo5xPaMKF78aAWPo5al0T4wfIBYKuxbGKu7jbEF5/Mszmox0DQX7jmjITV7A9+fRu6I2R5bxrZE+9RbAZZCtFAp5pWaKN34VPRxgBzMBajQvUSWJxqvjQhdw9PHcZo3hfg9dudpxeHQv6hLnNw8jrrjb7pg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=IG+yt2Na; 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="IG+yt2Na" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 34AB9C4CEE4; Thu, 17 Apr 2025 12:27:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744892836; bh=foYOSk+C4jWUa4BNln8QbxDRmDvP7m18xB7ecrYazbU=; h=Subject:To:Cc:From:Date:From; b=IG+yt2Naaisg1ZzXg310st1398bj6F0qH5qIOmUwX4sSiATIB3yDRqx6zSwV4gsP0 p/g5F7zmyIx57sWag4UitgzUiOnypCQw3Lce+RUcFfqMP0NRH14VsuV5OHnh4Bzrz9 2Bp+jqeh5SLIf3qnojjUPcf/YDYDnJYnddr8P+jQ= Subject: FAILED: patch "[PATCH] x86/e820: Fix handling of subpage regions when calculating" failed to apply to 6.12-stable tree To: myrrhperiwinkle@qtmlabs.xyz,ardb@kernel.org,dwmw@amazon.co.uk,hpa@zytor.com,io@r-ricci.it,keescook@chromium.org,len.brown@intel.com,mingo@kernel.org,rafael.j.wysocki@intel.com,torvalds@linux-foundation.org Cc: From: Date: Thu, 17 Apr 2025 14:24:35 +0200 Message-ID: <2025041735-reflector-backdrop-ceb9@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x f2f29da9f0d4367f6ff35e0d9d021257bb53e273 # git commit -s git send-email --to '' --in-reply-to '2025041735-reflector-backdrop-ceb9@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From f2f29da9f0d4367f6ff35e0d9d021257bb53e273 Mon Sep 17 00:00:00 2001 From: Myrrh Periwinkle Date: Sun, 6 Apr 2025 11:45:22 +0700 Subject: [PATCH] x86/e820: Fix handling of subpage regions when calculating nosave ranges in e820__register_nosave_regions() While debugging kexec/hibernation hangs and crashes, it turned out that the current implementation of e820__register_nosave_regions() suffers from multiple serious issues: - The end of last region is tracked by PFN, causing it to find holes that aren't there if two consecutive subpage regions are present - The nosave PFN ranges derived from holes are rounded out (instead of rounded in) which makes it inconsistent with how explicitly reserved regions are handled Fix this by: - Treating reserved regions as if they were holes, to ensure consistent handling (rounding out nosave PFN ranges is more correct as the kernel does not use partial pages) - Tracking the end of the last RAM region by address instead of pages to detect holes more precisely These bugs appear to have been introduced about ~18 years ago with the very first version of e820_mark_nosave_regions(), and its flawed assumptions were carried forward uninterrupted through various waves of rewrites and renames. [ mingo: Added Git archeology details, for kicks and giggles. ] Fixes: e8eff5ac294e ("[PATCH] Make swsusp avoid memory holes and reserved memory regions on x86_64") Reported-by: Roberto Ricci Tested-by: Roberto Ricci Signed-off-by: Myrrh Periwinkle Signed-off-by: Ingo Molnar Cc: Rafael J. Wysocki Cc: Ard Biesheuvel Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: David Woodhouse Cc: Len Brown Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20250406-fix-e820-nosave-v3-1-f3787bc1ee1d@qtmlabs.xyz Closes: https://lore.kernel.org/all/Z4WFjBVHpndct7br@desktop0a/ diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index 57120f0749cc..9d8dd8deb2a7 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -753,22 +753,21 @@ void __init e820__memory_setup_extended(u64 phys_addr, u32 data_len) void __init e820__register_nosave_regions(unsigned long limit_pfn) { int i; - unsigned long pfn = 0; + u64 last_addr = 0; for (i = 0; i < e820_table->nr_entries; i++) { struct e820_entry *entry = &e820_table->entries[i]; - if (pfn < PFN_UP(entry->addr)) - register_nosave_region(pfn, PFN_UP(entry->addr)); - - pfn = PFN_DOWN(entry->addr + entry->size); - if (entry->type != E820_TYPE_RAM) - register_nosave_region(PFN_UP(entry->addr), pfn); + continue; - if (pfn >= limit_pfn) - break; + if (last_addr < entry->addr) + register_nosave_region(PFN_DOWN(last_addr), PFN_UP(entry->addr)); + + last_addr = entry->addr + entry->size; } + + register_nosave_region(PFN_DOWN(last_addr), limit_pfn); } #ifdef CONFIG_ACPI