On 08/19/2015 11:38 PM, Dave Anderson wrote: > > > ----- Original Message ----- >> >> Hi, >> >> On 08/19/2015 12:02 PM, Baoquan He wrote: >>> On 08/19/15 at 09:21am, Nikolay Borisov wrote: >>>> Hello, >>>> >>>> I've recently noticed that when creating crashdumps the dmesg is not >>>> being saved. The error reported is this: "Missing the struct log size >>>> export". I've tested with both kernel 4.1.1 and 3.12.28. My version of >>>> kexec tools is : kexec-tools 2.0.9 released 04 June 2015. The kernel has >>>> been compiled with debugging info so the respective symbol should be >>>> exported but apparently it is not. Any ideas how to debug that? >>> >>> That would be more helpful if you can attach the 1st kernel and kdump >>> kernel console log. >> >> I just tested with 4.1.6 with the same result. I'm sending you a link to >> the bzImage in question >> http://georgi.unixsol.org/cruft/tmp/bzImage-4.1.6-clouder1 ( I assume >> you meant the bzImage, if you need I can provide the vmlinux as well). >> Unfortunately, I couldn't figure how to obtain the log of kdump in >> textual format (and didn't want to send pictures). Here are the 3 >> relevant lines (from memory): >> >> Saving vmcore-dmesg.txt >> Missing the struct log size export >> Error saving vmcore-dmesg.txt. >> >> Yet, when I load the crashdump inside the 'crash' utility and invoke the >> 'log' command the dmesg log is there. Whereas the vmcore-dmesg-incomplete.txt is empty. > > FYI -- the crash utility doesn't use the vmcoreinfo data for its "log" command, > but you can dump the vmcore's header contents, including the vmcoreinfo strings, > with the "help -n" command. For example: Thanks for the tip, using that I can confirm that the actual symbols are in the resulting vmcoreinfo: 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 So the required symbol is there (printk_log) but for some reason kexec cannot read it... I tried creating an uncompressed crash (removing the -c option from the makedumpfile command to no avail).. > > crash> help -n > ... [ cut ] ... > OSRELEASE=3.18.0-0.rc2.git2.1.slub1.fc21.x86_64 > PAGESIZE=4096 > SYMBOL(init_uts_ns)=ffffffff81e1b300 > SYMBOL(node_online_map)=ffffffff81fe8980 > SYMBOL(swapper_pg_dir)=ffffffff81e14000 > SYMBOL(_stext)=ffffffff810001c8 > SYMBOL(vmap_area_list)=ffffffff81efce50 > SYMBOL(mem_section)=ffffffff832eb180 > LENGTH(mem_section)=4096 > SIZE(mem_section)=32 > OFFSET(mem_section.section_mem_map)=0 > SIZE(page)=64 > SIZE(pglist_data)=156928 > SIZE(zone)=1984 > SIZE(free_area)=88 > SIZE(list_head)=16 > SIZE(nodemask_t)=128 > OFFSET(page.flags)=0 > OFFSET(page._count)=28 > OFFSET(page.mapping)=8 > OFFSET(page.lru)=32 > OFFSET(page._mapcount)=24 > OFFSET(page.private)=48 > OFFSET(pglist_data.node_zones)=0 > OFFSET(pglist_data.nr_zones)=156480 > OFFSET(pglist_data.node_start_pfn)=156560 > OFFSET(pglist_data.node_spanned_pages)=156576 > OFFSET(pglist_data.node_id)=156584 > OFFSET(zone.free_area)=392 > OFFSET(zone.vm_stat)=1664 > OFFSET(zone.spanned_pages)=120 > 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)=48 > LENGTH(zone.free_area)=11 > SYMBOL(log_buf)=ffffffff81e5f0c0 > SYMBOL(log_buf_len)=ffffffff81e5f0bc > SYMBOL(log_first_idx)=ffffffff831bee88 > SYMBOL(log_next_idx)=ffffffff831bee78 > 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)=5 > NUMBER(NR_FREE_PAGES)=0 > NUMBER(PG_lru)=5 > NUMBER(PG_private)=11 > NUMBER(PG_swapcache)=16 > NUMBER(PG_slab)=7 > NUMBER(PG_hwpoison)=23 > NUMBER(PG_head_mask)=16384 > NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE)=-128 > SYMBOL(free_huge_page)=ffffffff81239430 > SYMBOL(phys_base)=ffffffff81e1b010 > SYMBOL(init_level4_pgt)=ffffffff81e14000 > SYMBOL(node_data)=ffffffff81fe2d40 > LENGTH(node_data)=1024 > KERNELOFFSET=0 > CRASHTIME=141512763 > ... > > Dave >
