** Patch added: "lp1869465_xenial_v2.debdiff" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1869465/+attachment/5380773/+files/lp1869465_xenial_v2.debdiff
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1869465 Title: Kdump-Tools: Makedumpfile Failed, Falling Back To 'Cp' Status in linux package in Ubuntu: In Progress Status in linux source package in Xenial: In Progress Status in linux source package in Bionic: In Progress Status in linux source package in Eoan: In Progress Status in linux source package in Focal: In Progress Status in linux source package in Groovy: In Progress Status in linux package in Debian: New Bug description: [Impact] On some arm systems makedumpfile fails to translate virtual to physical addresses properly. This may result in makedumpfile looping forever exhausting all memory, or translating a virtual address to an invalid physical address and then failing and falling back to cp. The reason it cannot resolve some addresses is because the PMD mask is wrong. When physical address mask allows up to 48bits pmd mask should allow the same, currently pmd mask is set to 40bits (see commit [1]). Commit [1] fixes this bug. [Test Case] To hit this bug you need a system that needs physical addresses over 1TB. This may be either because you have a lot of memory or because the firmware mapped some memory above 1TB for some reason [1]. A user hit this bug because firmware mapped memory above 1TB and provided a dump so I could reproduce the bug when running makedumpfile on the dump. [Regression Potential] This commit changes the PMD_SECTION_MASK for arm64. So any regression potential would only affect arm64 systems. In addition PMD_SECTION_MASK is used in translation from virtual to physical addresses and therefore any regression would happen during this process. [Other] [1] https://github.com/makedumpfile/makedumpfile/commit/7242ae4cb5288df626f464ced0a8b60fd669100b When testing kdump on Ubuntu 18.04.4 (arm64) GA kernel, makedumpfile fails. The test steps are as follows: # echo 1> / proc / sys / kernel / sysrq # echo c> / proc / sysrq-trigger The logs are as follows: kdump-tools[646]: starting kdump-tools: * running makedumpfile -c -d 31 /proc/vmcore /var/crash/202003251128/dump-incomplete kdump-tools[646]: readpage_elf: Attempt to read non-existent page at 0x0 kdump-tools[646]: readmem: type_addr: 1, addr:ff0, size:8 kdump-tools[646]: vaddr_to_paddr_arm64: Can't read pud kdump-tools[646]: readmem: Can't convert a virtual address(ffff9e653690) to physical address. kdump-tools[646]: readmem: type_addr: 0, addr:ffff9e653690, size:1032 kdump-tools[646]: validate_mem_section: Can't read mem_section array. kdump-tools[646]: get_mem_section: Could not validate mem_section. kdump-tools[646]: get_mm_sparsemem: Can't get the address of mem_section. kdump-tools[646]: makedumpfile Failed. kdump-tools[646]: * kdump-tools: makedumpfile failed, falling back to 'cp' But when I use the HWE kernel, I find that there is no such problem. The HEW kernel version: 5.3.0-42-generic To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1869465/+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
