This option will make --dump-dmesg save only the part of the dmesg
buffer since it was last cleared on the crashed kernel (with
dmesg --clear and such) instead of the whole buffer since boot or
wrap-around. It works on kernels with commit f468908bb55a ("printk:
add clear_idx symbol to vmcoreinfo") merged in v4.6 and otherwise
will default to the regular behavior.Signed-off-by: Ivan Delalande <[email protected]> --- makedumpfile.8 | 8 +++++++- makedumpfile.c | 21 +++++++++++++++++++-- makedumpfile.h | 3 +++ 3 files changed, 29 insertions(+), 3 deletions(-) diff --git a/makedumpfile.8 b/makedumpfile.8 index 9932364..76a8d6e 100644 --- a/makedumpfile.8 +++ b/makedumpfile.8 @@ -20,7 +20,7 @@ makedumpfile \- make a small dumpfile of kdump .br \fBmakedumpfile\fR [\fIOPTION\fR] [\-\-xen-syms \fIXEN-SYMS\fR|\-\-xen-vmcoreinfo \fIVMCOREINFO\fR] \fIVMCORE\fR \fIDUMPFILE\fR .br -\fBmakedumpfile\fR \-\-dump-dmesg [\-x \fIVMLINUX\fR|\-i \fIVMCOREINFO\fR] \fIVMCORE\fR \fILOGFILE\fR +\fBmakedumpfile\fR \-\-dump-dmesg [\-\-partial-dmesg] [\-x \fIVMLINUX\fR|\-i \fIVMCOREINFO\fR] \fIVMCORE\fR \fILOGFILE\fR .br \fBmakedumpfile\fR [\fIOPTION\fR] \-x \fIVMLINUX\fR \-\-diskset=\fIVMCORE1\fR \-\-diskset=\fIVMCORE2\fR [\-\-diskset=\fIVMCORE3\fR ..] \fIDUMPFILE\fR .br @@ -586,6 +586,12 @@ it is necessary to specfiy [\-x \fIVMLINUX\fR] or [\-i \fIVMCOREINFO\fR]. .TP +\fB\-\-partial-dmesg\fR +This option will make --dump-dmesg extract only dmesg logs since that buffer was +last cleared on the crashed kernel, through "dmesg --clear" for example. + + +.TP \fB\-\-mem-usage\fR This option is only for x86_64. This option is used to show the page numbers of current system in different diff --git a/makedumpfile.c b/makedumpfile.c index 95cc5ef..7c88203 100644 --- a/makedumpfile.c +++ b/makedumpfile.c @@ -1498,6 +1498,7 @@ get_symbol_info(void) SYMBOL_INIT(log_buf_len, "log_buf_len"); SYMBOL_INIT(log_end, "log_end"); SYMBOL_INIT(log_first_idx, "log_first_idx"); + SYMBOL_INIT(clear_idx, "clear_idx"); SYMBOL_INIT(log_next_idx, "log_next_idx"); SYMBOL_INIT(max_pfn, "max_pfn"); SYMBOL_INIT(modules, "modules"); @@ -2115,6 +2116,7 @@ write_vmcoreinfo_data(void) WRITE_SYMBOL("log_buf_len", log_buf_len); WRITE_SYMBOL("log_end", log_end); WRITE_SYMBOL("log_first_idx", log_first_idx); + WRITE_SYMBOL("clear_idx", clear_idx); WRITE_SYMBOL("log_next_idx", log_next_idx); WRITE_SYMBOL("max_pfn", max_pfn); WRITE_SYMBOL("high_memory", high_memory); @@ -2509,6 +2511,7 @@ read_vmcoreinfo(void) READ_SYMBOL("log_buf_len", log_buf_len); READ_SYMBOL("log_end", log_end); READ_SYMBOL("log_first_idx", log_first_idx); + READ_SYMBOL("clear_idx", clear_idx); READ_SYMBOL("log_next_idx", log_next_idx); READ_SYMBOL("max_pfn", max_pfn); READ_SYMBOL("high_memory", high_memory); @@ -5025,6 +5028,7 @@ dump_dmesg() int log_buf_len, length_log, length_oldlog, ret = FALSE; unsigned long index, log_buf, log_end; unsigned int idx, log_first_idx, log_next_idx; + unsigned long long first_idx_sym; unsigned long log_end_2_6_24; unsigned log_end_2_6_25; char *log_buffer = NULL, *log_ptr = NULL; @@ -5058,7 +5062,13 @@ dump_dmesg() ERRMSG("Can't find variable-length record symbols"); return FALSE; } else { - if (!readmem(VADDR, SYMBOL(log_first_idx), &log_first_idx, + if (info->flag_partial_dmesg + && SYMBOL(clear_idx) != NOT_FOUND_SYMBOL) + first_idx_sym = SYMBOL(clear_idx); + else + first_idx_sym = SYMBOL(log_first_idx); + + if (!readmem(VADDR, first_idx_sym, &log_first_idx, sizeof(log_first_idx))) { ERRMSG("Can't get log_first_idx.\n"); return FALSE; @@ -5102,7 +5112,10 @@ dump_dmesg() DEBUG_MSG("log_buf : %lx\n", log_buf); DEBUG_MSG("log_end : %lx\n", log_end); DEBUG_MSG("log_buf_len : %d\n", log_buf_len); - DEBUG_MSG("log_first_idx : %u\n", log_first_idx); + if (info->flag_partial_dmesg) + DEBUG_MSG("clear_idx : %u\n", log_first_idx); + else + DEBUG_MSG("log_first_idx : %u\n", log_first_idx); DEBUG_MSG("log_next_idx : %u\n", log_next_idx); if ((log_buffer = malloc(log_buf_len)) == NULL) { @@ -11022,6 +11035,7 @@ static struct option longopts[] = { {"message-level", required_argument, NULL, OPT_MESSAGE_LEVEL}, {"vtop", required_argument, NULL, OPT_VTOP}, {"dump-dmesg", no_argument, NULL, OPT_DUMP_DMESG}, + {"partial-dmesg", no_argument, NULL, OPT_PARTIAL_DMESG}, {"config", required_argument, NULL, OPT_CONFIG}, {"help", no_argument, NULL, OPT_HELP}, {"diskset", required_argument, NULL, OPT_DISKSET}, @@ -11135,6 +11149,9 @@ main(int argc, char *argv[]) case OPT_DUMP_DMESG: info->flag_dmesg = 1; break; + case OPT_PARTIAL_DMESG: + info->flag_partial_dmesg = 1; + break; case OPT_MEM_USAGE: info->flag_mem_usage = 1; break; diff --git a/makedumpfile.h b/makedumpfile.h index 6ea8cc4..d3b7532 100644 --- a/makedumpfile.h +++ b/makedumpfile.h @@ -1241,6 +1241,7 @@ struct DumpInfo { int flag_force; /* overwrite existing stuff */ int flag_exclude_xen_dom;/* exclude Domain-U from xen-kdump */ int flag_dmesg; /* dump the dmesg log out of the vmcore file */ + int flag_partial_dmesg; /* dmesg dump only from the last cleared index*/ int flag_mem_usage; /*show the page number of memory in different use*/ int flag_use_printk_log; /* did we read printk_log symbol name? */ int flag_nospace; /* the flag of "No space on device" error */ @@ -1529,6 +1530,7 @@ struct symbol_table { unsigned long long log_buf_len; unsigned long long log_end; unsigned long long log_first_idx; + unsigned long long clear_idx; unsigned long long log_next_idx; unsigned long long max_pfn; unsigned long long node_remap_start_vaddr; @@ -2268,6 +2270,7 @@ struct elf_prstatus { #define OPT_SPLITBLOCK_SIZE OPT_START+14 #define OPT_WORKING_DIR OPT_START+15 #define OPT_NUM_THREADS OPT_START+16 +#define OPT_PARTIAL_DMESG OPT_START+17 /* * Function Prototype. -- 2.13.1 -- Ivan Delalande Kernel Team - Vancouver - #³ A3Y20 Phone: 7342 | Mobile: 604 600 5313 _______________________________________________ kexec mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kexec
