Hello, Sorry to cross post on both ML, I'm not sure which one would be the most suitable. Issue on analysis with crash-7.3.1 on a Centos 8 machine: crash: read error: kernel virtual address: ffff8f4fff7fc000 type: "memory section root table" Crash machine has a Rocky Linux 8.5 based kernel with following config options: * CONFIG_RANDOMIZE_BASE=y * CONFIG_RANDOMIZE_MEMORY=y * CONFIG_SPARSEMEM_MANUAL=y * CONFIG_SPARSEMEM=y * CONFIG_SPARSEMEM_EXTREME=y * CONFIG_SPARSEMEM_VMEMMAP_ENABLE=y * CONFIG_KEXEC_CORE=y * CONFIG_KEXEC=y * CONFIG_KEXEC_FILE=y Kexec-tools package is from Centos Stream repo: kexec-tools-2.0.20-68.el8.2.5ale.x86_64 /proc/vmcore is packaged with : /sbin/makedumpfile -D -d 0 -c --message-level 15 /proc/vmcore /tmpd/crashdump-${linux_ver}-${date_time} At kernel panic, I get: Dumping memory to crash partition This may take a while, please wait... makedumpfile: version 1.7.0 (released on 8 Nov 2021) command line: /sbin/makedumpfile -D -d 0 -c --message-level 15 /proc/vmcore /tmpd/crashdump--20220329-1538 sadump: does not have partition header sadump: read dump device as unknown format sadump: unknown format phys_start phys_end virt_start virt_end LOAD[ 0] 8000000 9a2c000 ffffffff8a400000 ffffffff8be2c000 LOAD[ 1] 100000 3b000000 ffff8f4fc0100000 ffff8f4ffb000000 LOAD[ 2] 3d800000 3e341000 ffff8f4ffd800000 ffff8f4ffe341000 LOAD[ 3] 3ed7b000 3eee2000 ffff8f4ffed7b000 ffff8f4ffeee2000 LOAD[ 4] 3f63a000 3f800000 ffff8f4fff63a000 ffff8f4fff800000 Linux kdump VMCOREINFO : OSRELEASE=4.18.0-348.12.2.el8_5-ale PAGESIZE=4096 page_size : 4096 SYMBOL(init_uts_ns)=ffffffff8b653600 SYMBOL(node_online_map)=ffffffff8b7630a8 SYMBOL(swapper_pg_dir)=ffffffff8b64c000 SYMBOL(_stext)=ffffffff8a400000 SYMBOL(vmap_area_list)=ffffffff8b6a47a0 SYMBOL(mem_map)=ffffffff8bd25828 SYMBOL(contig_page_data)=ffffffff8b726600 SYMBOL(mem_section)=ffff8f4fff7fc000 LENGTH(mem_section)=2048 SIZE(mem_section)=16 OFFSET(mem_section.section_mem_map)=0 SIZE(page)=64 SIZE(pglist_data)=5696 SIZE(zone)=1216 SIZE(free_area)=72 SIZE(list_head)=16 SIZE(nodemask_t)=8 OFFSET(page.flags)=0 OFFSET(page._refcount)=52 OFFSET(page.mapping)=24 OFFSET(page.lru)=8 OFFSET(page._mapcount)=48 OFFSET(page.private)=40 OFFSET(page.compound_dtor)=16 OFFSET(page.compound_order)=17 OFFSET(page.compound_head)=8 OFFSET(pglist_data.node_zones)=0 OFFSET(pglist_data.nr_zones)=4944 OFFSET(pglist_data.node_start_pfn)=4952 OFFSET(pglist_data.node_spanned_pages)=4968 OFFSET(pglist_data.node_id)=4976 OFFSET(zone.free_area)=192 OFFSET(zone.vm_stat)=1104 OFFSET(zone.spanned_pages)=96 OFFSET(free_area.free_list)=0 OFFSET(list_head.next)=0 OFFSET(list_head.prev)=8 OFFSET(vmap_area.va_start)=0 OFFSET(vmap_area.list)=40 LENGTH(zone.free_area)=11 SYMBOL(log_buf)=ffffffff8b67d3c0 SYMBOL(log_buf_len)=ffffffff8b67d3bc SYMBOL(log_first_idx)=ffffffff8bd1a3d8 SYMBOL(clear_idx)=ffffffff8bd1a3a4 SYMBOL(log_next_idx)=ffffffff8bd1a3c8 SIZE(printk_log)=16 OFFSET(printk_log.ts_nsec)=0 OFFSET(printk_log.len)=8 OFFSET(printk_log.text_len)=10 OFFSET(printk_log.dict_len)=12 LENGTH(free_area.free_list)=4 NUMBER(NR_FREE_PAGES)=0 NUMBER(PG_lru)=5 NUMBER(PG_private)=12 NUMBER(PG_swapcache)=9 NUMBER(PG_swapbacked)=18 NUMBER(PG_slab)=8 NUMBER(PG_head_mask)=32768 NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE)=-129 NUMBER(HUGETLB_PAGE_DTOR)=2 NUMBER(PAGE_OFFLINE_MAPCOUNT_VALUE)=-257 SYMBOL(alcatel_dump_info)=ffffffff8b647000 NUMBER(phys_base)=-37748736 SYMBOL(init_top_pgt)=ffffffff8b64c000 NUMBER(pgtable_l5_enabled)=0 KERNELOFFSET=9400000 NUMBER(KERNEL_IMAGE_SIZE)=1073741824 NUMBER(sme_mask)=0 CRASHTIME=1648561077 phys_base : fffffffffdc00000 (vmcoreinfo) max_mapnr : 3f800 There is enough free memory to be done in one cycle. Buffer size for the cyclic mode: 65024 page_offset : ffff8f4fc0000000 (pt_load) num of NODEs : 1 Memory type : SPARSEMEM_EX mem_map pfn_start pfn_end mem_map[ 0] ffff8f4ffa000000 0 8000 mem_map[ 1] ffff8f4ffa200000 8000 10000 mem_map[ 2] ffff8f4ffa400000 10000 18000 mem_map[ 3] ffff8f4ffa600000 18000 20000 mem_map[ 4] ffff8f4ffa800000 20000 28000 mem_map[ 5] ffff8f4ffaa00000 28000 30000 mem_map[ 6] ffff8f4ffac00000 30000 38000 mem_map[ 7] ffff8f4ffae00000 38000 3f800 mmap() is available on the kernel. Copying data : [100.0 %] | eta: 0s Writing erase info... offset_eraseinfo: ca157f3, size_eraseinfo: 0 The dumpfile is saved to /tmpd/crashdump--20220329-1538. makedumpfile Completed. Rebooting the system... And latest logs from a 'crash -d 7' command are: <...> kernel NR_CPUS: 2 <readmem: ffffffff8bd25820, KVADDR, "high_memory", 8, (FOE), 55e05ecb3608> <read_diskdump: addr: ffffffff8bd25820 paddr: 9925820 cnt: 8> PAGESIZE=4096 mem_section_size = 16384 NR_SECTION_ROOTS = 2048 NR_MEM_SECTIONS = 524288 SECTIONS_PER_ROOT = 256 SECTION_ROOT_MASK = 0xff PAGES_PER_SECTION = 32768 <readmem: ffffffff8bd26db0, KVADDR, "mem_section", 8, (FOE), 7ffdbf96a440> <read_diskdump: addr: ffffffff8bd26db0 paddr: 9926db0 cnt: 8> <readmem: ffff8f4fff7fc000, KVADDR, "memory section root table", 16384, (FOE), 55e06391b840> <read_diskdump: addr: ffff8f4fff7fc000 paddr: 3f7fc000 cnt: 4096> crash: read error: kernel virtual address: ffff8f4fff7fc000 type: "memory section root table" The address (ffff8f4fff7fc000) seems to be inside the LOAD[4] range and is recorded as 'mem_section' with VMCOREINFO. What's wrong ? Where should I look at ? Thanks. Best regards, Patrick Agrain