Re: [PATCH] dump-dmesg: Understand >= v3.11-rc4 dmesg

Atsushi Kumagai
2013-09-06T06:47:19Z

HelloLubomir,

(2013/09/02 5:04), Lubomir Rintel wrote:
> Symbol name changed with the following commit:
> 62e32ac printk: rename struct log to struct printk_log
>
> Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
> Cc: Louis Bouchard <louis.bouchard@canonical.com>
> Cc: Masaki Tachibana <tachibana@mxm.nes.nec.co.jp>
> Cc: Minoru Usui <usui@mxm.nes.nec.co.jp>
> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
> Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
> ---
> makedumpfile.c | 56 ++++++++++++++++++++++++++++++++++++++------------------
> makedumpfile.h | 6 +++---
> 2 files changed, 41 insertions(+), 21 deletions(-)
>
> diff --git a/makedumpfile.c b/makedumpfile.c
> index b42565c..5b04048 100644
> --- a/makedumpfile.c
> +++ b/makedumpfile.c
> @@ -1389,10 +1389,17 @@ get_structure_info(void)
> OFFSET_INIT(elf64_phdr.p_paddr, "elf64_phdr", "p_paddr");
> OFFSET_INIT(elf64_phdr.p_memsz, "elf64_phdr", "p_memsz");
>
> - SIZE_INIT(log, "log");
> - OFFSET_INIT(log.ts_nsec, "log", "ts_nsec");
> - OFFSET_INIT(log.len, "log", "len");
> - OFFSET_INIT(log.text_len, "log", "text_len");
> + SIZE_INIT(printk_log, "printk_log");
> + if (SIZE(printk_log) != NOT_FOUND_STRUCTURE) {
> + OFFSET_INIT(printk_log.ts_nsec, "printk_log", "ts_nsec");
> + OFFSET_INIT(printk_log.len, "printk_log", "len");
> + OFFSET_INIT(printk_log.text_len, "printk_log", "text_len");
> + } else {
> + SIZE_INIT(printk_log, "log");
> + OFFSET_INIT(printk_log.ts_nsec, "log", "ts_nsec");
> + OFFSET_INIT(printk_log.len, "log", "len");
> + OFFSET_INIT(printk_log.text_len, "log", "text_len");
> + }
>
> return TRUE;
> }
> @@ -1593,7 +1600,8 @@ write_vmcoreinfo_data(void)
> WRITE_STRUCTURE_SIZE("node_memblk_s", node_memblk_s);
> WRITE_STRUCTURE_SIZE("nodemask_t", nodemask_t);
> WRITE_STRUCTURE_SIZE("pageflags", pageflags);
> - WRITE_STRUCTURE_SIZE("log", log);
> + WRITE_STRUCTURE_SIZE("printk_log", printk_log);
> + WRITE_STRUCTURE_SIZE("log", printk_log); /* compat */

To export the size of struct printk_log as the size of struct log
for old makedumpfile doesn't provide compatibility, because old
makedumpfile can't extract dmesg after all since the variable-length
record format isn't supported. (except makedumpfile-1.5.2, 1.5.3 and 1.5.4)
The compatibility you said is only for those versions, so that's
incomplete and not acceptable.

I think ether log or printk_log should be written based on the original
symbol name, to write both is redundant and confusing in many cases.

> /*
> * write the member offset of 1st kernel
> @@ -1628,9 +1636,13 @@ write_vmcoreinfo_data(void)
> WRITE_MEMBER_OFFSET("vm_struct.addr", vm_struct.addr);
> WRITE_MEMBER_OFFSET("vmap_area.va_start", vmap_area.va_start);
> WRITE_MEMBER_OFFSET("vmap_area.list", vmap_area.list);
> - WRITE_MEMBER_OFFSET("log.ts_nsec", log.ts_nsec);
> - WRITE_MEMBER_OFFSET("log.len", log.len);
> - WRITE_MEMBER_OFFSET("log.text_len", log.text_len);
> + WRITE_MEMBER_OFFSET("printk_log.ts_nsec", printk_log.ts_nsec);
> + WRITE_MEMBER_OFFSET("printk_log.len", printk_log.len);
> + WRITE_MEMBER_OFFSET("printk_log.text_len", printk_log.text_len);
> + /* Compatibility with pre-3.11-rc4 */
> + WRITE_MEMBER_OFFSET("log.ts_nsec", printk_log.ts_nsec);
> + WRITE_MEMBER_OFFSET("log.len", printk_log.len);
> + WRITE_MEMBER_OFFSET("log.text_len", printk_log.text_len);

The same as above can be said.

Thanks
Atsushi Kumagai

> if (SYMBOL(node_data) != NOT_FOUND_SYMBOL)
> WRITE_ARRAY_LENGTH("node_data", node_data);
> @@ -1909,7 +1921,6 @@ read_vmcoreinfo(void)
> READ_STRUCTURE_SIZE("node_memblk_s", node_memblk_s);
> READ_STRUCTURE_SIZE("nodemask_t", nodemask_t);
> READ_STRUCTURE_SIZE("pageflags", pageflags);
> - READ_STRUCTURE_SIZE("log", log);
>
> READ_MEMBER_OFFSET("page.flags", page.flags);
> READ_MEMBER_OFFSET("page._count", page._count);
> @@ -1940,9 +1951,18 @@ read_vmcoreinfo(void)
> READ_MEMBER_OFFSET("vm_struct.addr", vm_struct.addr);
> READ_MEMBER_OFFSET("vmap_area.va_start", vmap_area.va_start);
> READ_MEMBER_OFFSET("vmap_area.list", vmap_area.list);
> - READ_MEMBER_OFFSET("log.ts_nsec", log.ts_nsec);
> - READ_MEMBER_OFFSET("log.len", log.len);
> - READ_MEMBER_OFFSET("log.text_len", log.text_len);
> +
> + READ_STRUCTURE_SIZE("printk_log", printk_log);
> + if (SIZE(printk_log) != NOT_FOUND_STRUCTURE) {
> + READ_MEMBER_OFFSET("printk_log.ts_nsec", printk_log.ts_nsec);
> + READ_MEMBER_OFFSET("printk_log.len", printk_log.len);
> + READ_MEMBER_OFFSET("printk_log.text_len", printk_log.text_len);
> + } else {
> + READ_STRUCTURE_SIZE("log", printk_log);
> + READ_MEMBER_OFFSET("log.ts_nsec", printk_log.ts_nsec);
> + READ_MEMBER_OFFSET("log.len", printk_log.len);
> + READ_MEMBER_OFFSET("log.text_len", printk_log.text_len);
> + }
>
> READ_ARRAY_LENGTH("node_data", node_data);
> READ_ARRAY_LENGTH("pgdat_list", pgdat_list);
> @@ -3705,13 +3725,13 @@ dump_log_entry(char *logptr, int fp)
> ulonglong nanos;
> ulong rem;
>
> - text_len = USHORT(logptr + OFFSET(log.text_len));
> - ts_nsec = ULONGLONG(logptr + OFFSET(log.ts_nsec));
> + text_len = USHORT(logptr + OFFSET(printk_log.text_len));
> + ts_nsec = ULONGLONG(logptr + OFFSET(printk_log.ts_nsec));
>
> nanos = (ulonglong)ts_nsec / (ulonglong)1000000000;
> rem = (ulonglong)ts_nsec % (ulonglong)1000000000;
>
> - msg = logptr + SIZE(log);
> + msg = logptr + SIZE(printk_log);
>
> sprintf(buf, "[%5lld.%06ld] ", nanos, rem/1000);
>
> @@ -3749,7 +3769,7 @@ log_from_idx(unsigned int idx, char *logbuf)
> * the buffer.
> */
>
> - msglen = USHORT(logptr + OFFSET(log.len));
> + msglen = USHORT(logptr + OFFSET(printk_log.len));
> if (!msglen)
> logptr = logbuf;
>
> @@ -3770,9 +3790,9 @@ log_next(unsigned int idx, char *logbuf)
> * return the one after that.
> */
>
> - msglen = USHORT(logptr + OFFSET(log.len));
> + msglen = USHORT(logptr + OFFSET(printk_log.len));
> if (!msglen) {
> - msglen = USHORT(logbuf + OFFSET(log.len));
> + msglen = USHORT(logbuf + OFFSET(printk_log.len));
> return msglen;
> }
>
> diff --git a/makedumpfile.h b/makedumpfile.h
> index a5826e0..5b96c11 100644
> --- a/makedumpfile.h
> +++ b/makedumpfile.h
> @@ -1198,7 +1198,7 @@ struct size_table {
> long cpumask_t;
> long kexec_segment;
> long elf64_hdr;
> - long log;
> + long printk_log;
>
> long pageflags;
> };
> @@ -1337,11 +1337,11 @@ struct offset_table {
> long p_memsz;
> } elf64_phdr;
>
> - struct log_s {
> + struct printk_log_s {
> long ts_nsec;
> long len;
> long text_len;
> - } log;
> + } printk_log;
>
> };
>
>