Re: [Crash-utility] [PATCH] makedumpfile: Save utsname data into disk_dump_header.(Re: makedumpfile question / request)

>>> Is there a reason that makedumpfile does not fill in the utsname structure >>> in the compressed dumpfile's header? >> Thank you for good point. >> >> makedumpfile does not fill it because makedumpfile might not be able to >> get kernel debug information (containing symbol system_utsname/init_uts_ns). >> makedumpfile does not need kernel debug information if dump_level is 0 or 1, >> and it does not read a new_utsname structure. (check_release() is not called.) >> >> >>> The data structure does get read into a local new_utsname structure in the >>> check_release() function, but it doesn't get saved and copied into the >>> disk_dump_header in write_kdump_header(). >>> >>> It would be helpful if that were in place as a quick ID for what the >>> compressed dumpfile contains. >> I feel that is worth. >> How about saving new_utsname data into disk_dump_header only if dump_level >> is 2 or bigger ? > Well, that's certainly preferable than the way it is now. > > But let me ask you this... > > Given that the init_uts_ns structure is always located in: > > (1) unity-mapped memory, or in a mapped kernel region for x86_64/ia64, and > (2) that your initial() function calls get_phys_base() in all cases, > > can't you just strip the relevant unity-mapping from the supplied > VMCOREINFO/init_uts_ns symbol value, apply the phys_base, and then > read it from the vmcore file? Thank you for the comment. We can do it by the attached patch.

--- [PATCH] Save utsname data into disk_dump_header. By this patch, makedumpfile saves utsname data into disk_dump_header. The crash utility can output the data by 'help -n' command: crash> help -n diskdump_data: flags: 6 (KDUMP_CMPRS_LOCAL|ERROR_EXCLUDED) dfd: 3 ofp: 3b29b4d760 machine_type: 62 (EM_X86_64) header: c34c70 signature: "KDUMP " header_version: 2 utsname: sysname: Linux nodename: localhost.localdomain release: 2.6.29-rc7 version: #1 SMP Mon Mar 9 11:20:46 JST 2009 machine: x86_64 domainname: (none) timestamp: [snip] Signed-off-by: Ken'ichi Ohmichi <oomichi(a)mxs.nes.nec.co.jp&gt; --- diff -puN a/makedumpfile.c b/makedumpfile.c --- a/makedumpfile.c 2009-04-20 15:26:23.000000000 +0900 +++ b/makedumpfile.c 2009-04-21 12:48:00.000000000 +0900 @@ -382,9 +382,8 @@ fallback_to_current_page_size(void) } int -check_release(void) +get_utsname(struct utsname *system_utsname) { - struct utsname system_utsname; unsigned long utsname; /* @@ -398,13 +397,18 @@ check_release(void) ERRMSG("Can't get the symbol of system_utsname.\n"); return FALSE; } - if (!readmem(VADDR, utsname, &system_utsname, sizeof(struct utsname))){ + if (!readmem(VADDR, utsname, system_utsname, sizeof(struct utsname))){ ERRMSG("Can't get the address of system_utsname.\n"); return FALSE; } + return TRUE; +} +int +check_release(void) +{ if (info->flag_read_vmcoreinfo) { - if (strcmp(system_utsname.release, info->release)) { + if (strcmp(info->system_utsname.release, info->release)) { ERRMSG("%s and %s don't match.\n", info->name_vmcoreinfo, info->name_memory); retcd = WRONG_RELEASE; @@ -412,7 +416,7 @@ check_release(void) } } - info->kernel_version = get_kernel_version(system_utsname.release); + info->kernel_version = get_kernel_version(info->system_utsname.release); if (info->kernel_version == FALSE) { if (!info->flag_read_vmcoreinfo) ERRMSG("Or %s and %s don't match.\n", @@ -3378,7 +3382,7 @@ get_mem_map(void) int initial(void) { - int flag_need_debuginfo; + int flag_get_debuginfo = FALSE, flag_need_debuginfo = FALSE; if (!(vt.mem_flags & MEMORY_XEN) && info->flag_exclude_xen_dom) { MSG("'-X' option is disable,"); @@ -3398,6 +3402,7 @@ initial(void) if (!read_vmcoreinfo()) return FALSE; close_vmcoreinfo(); + flag_get_debuginfo = TRUE; /* * Get the debug information for analysis from the kernel file */ @@ -3413,6 +3418,7 @@ initial(void) if (!get_srcfile_info()) return FALSE; + flag_get_debuginfo = TRUE; } else { /* * Check whether /proc/vmcore contains vmcoreinfo, @@ -3438,6 +3444,7 @@ initial(void) if (!read_vmcoreinfo_from_vmcore(info->offset_vmcoreinfo, info->size_vmcoreinfo, FALSE)) return FALSE; + flag_get_debuginfo = TRUE; } if (!get_value_for_old_linux()) @@ -3454,6 +3461,12 @@ out: if (!get_max_mapnr()) return FALSE; + if (flag_get_debuginfo) { + if (!get_machdep_info()) + return FALSE; + if (!get_utsname(&info->system_utsname)) + return FALSE; + } if ((info->max_dump_level <= DL_EXCLUDE_ZERO) && !info->flag_dmesg) flag_need_debuginfo = FALSE; else @@ -3465,10 +3478,6 @@ out: else return TRUE; } - - if (!get_machdep_info()) - return FALSE; - if (!check_release()) return FALSE; @@ -4969,6 +4978,7 @@ write_kdump_header(void) dh->bitmap_blocks = divideup(info->len_bitmap, dh->block_size); memcpy(&dh->timestamp, &info->timestamp, sizeof(dh->timestamp)); + memcpy(&dh->utsname, &info->system_utsname, sizeof(dh->utsname)); size = sizeof(struct disk_dump_header); if (!write_buffer(info->fd_dumpfile, 0, dh, size, info->name_dumpfile)) diff -puN a/makedumpfile.h b/makedumpfile.h --- a/makedumpfile.h 2009-04-20 15:26:23.000000000 +0900 +++ b/makedumpfile.h 2009-04-21 12:47:58.000000000 +0900 @@ -750,6 +750,7 @@ struct splitting_info { struct DumpInfo { int32_t kernel_version; /* version of first kernel*/ struct timeval timestamp; + struct utsname system_utsname; /* * General info: -- Crash-utility mailing list Crash-utility(a)redhat.com https://www.redhat.com/mailman/listinfo/crash-utility