[PATCH] makedumpfile: Save utsname data into disk_dump_header.(Re: makedumpfile question / request)
Ken'ichi Ohmichi
oomichi at mxs.nes.nec.co.jp
Mon Apr 20 23:26:13 EDT 2009
Hi Dave,
Dave Anderson wrote:
>>> 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.
Thanks
Ken'ichi Ohmichi
---
[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 at mxs.nes.nec.co.jp>
---
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:
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