For item 2: * Confirm that the patched makedumpfile works as expected on a system known to experience the issue.
Unfortunately I'm no longer able to reproduce the original issue. Even running on the same hardware where this was originally noticed, with the same kernel version (5.13.0-1027-oracle), makedumpfile from focal-updates/main (1:1.6.7-1ubuntu2.4) is just working well: [ 53.223512] kdump-tools[693]: Starting kdump-tools: [ 53.623944] kdump-tools[702]: * running makedumpfile -c -d 31 /proc/vmcore /var/crash/202312151415/dump-incomplete Copying data : [ 196.965120] reboot: Restarting system [ 22.0 %] | Unfortunately I don't have the information and I don't have access to the original system to check what version of makedumpfile it was using back then, so I could test the exact same makedumpfile+kernel versions. I also tested kernel 5.13.0-1027-oracle + makedumpfile 1:1.6.7-1ubuntu2 from focal/main, and in this combinarion, makedumpfile fails with a similar, but slightly different error, then falls back to cp: [ 53.721130] kdump-tools[690]: Starting kdump-tools: [ 54.121624] kdump-tools[699]: * running makedumpfile -c -d 31 /proc/vmcore /var/crash/202312151434/dump-incomplete [ 54.249624] kdump-tools[719]: get_mm_sparsemem: Can't get the address of mem_section. [ 54.345410] kdump-tools[719]: The kernel version is not supported. [ 54.425405] kdump-tools[719]: The makedumpfile operation may be incomplete. [ 54.517391] kdump-tools[719]: makedumpfile Failed. [ 54.577916] kdump-tools[699]: * kdump-tools: makedumpfile failed, falling back to 'cp' However, using the latest makedumpfile from focal-updates/main (1:1.6.7-1ubuntu2.4) fixes this situation, as mentioned / shown above. Due to this reason, I can't conclude the item 2. I'll work now on 1. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to makedumpfile in Ubuntu. https://bugs.launchpad.net/bugs/1970672 Title: makedumpfile falls back to cp with "__vtop4_x86_64: Can't get a valid pmd_pte." Status in makedumpfile package in Ubuntu: Fix Released Status in makedumpfile source package in Focal: Fix Committed Bug description: [Impact] * On Focal with an HWE (>=5.12) kernel, makedumpfile can sometimes fail with "__vtop4_x86_64: Can't get a valid pmd_pte." * makedumpfile falls back to cp for the dump, resulting in extremely large vmcores. This can impact both collection and analysis due to lack of space for the resulting vmcore. * This is fixed in upstream commit present in versions 1.7.0 and 1.7.1: https://github.com/makedumpfile/makedumpfile/commit/646456862df8926ba10dd7330abf3bf0f887e1b6 commit 646456862df8926ba10dd7330abf3bf0f887e1b6 Author: Kazuhito Hagio <k-hagio...@nec.com> Date: Wed May 26 14:31:26 2021 +0900 [PATCH] Increase SECTION_MAP_LAST_BIT to 5 * Required for kernel 5.12 Kernel commit 1f90a3477df3 ("mm: teach pfn_to_online_page() about ZONE_DEVICE section collisions") added a section flag (SECTION_TAINT_ZONE_DEVICE) and causes makedumpfile an error on some machines like this: __vtop4_x86_64: Can't get a valid pmd_pte. readmem: Can't convert a virtual address(ffffe2bdc2000000) to physical address. readmem: type_addr: 0, addr:ffffe2bdc2000000, size:32768 __exclude_unnecessary_pages: Can't read the buffer of struct page. create_2nd_bitmap: Can't exclude unnecessary pages. Increase SECTION_MAP_LAST_BIT to 5 to fix this. The bit had not been used until the change, so we can just increase the value. Signed-off-by: Kazuhito Hagio <k-hagio...@nec.com> [Test Plan] * Confirm that makedumpfile works as expected by triggering a kdump. * Confirm that the patched makedumpfile works as expected on a system known to experience the issue. * Confirm that the patched makedumpfile is able to work with a cp- generated known affected vmcore to compress it. The unpatched version fails. [Where problems could occur] * This change could adversely affect the collection/compression of vmcores during a kdump situation resulting in fallback to cp. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/makedumpfile/+bug/1970672/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
