[PATCH] makedumpfile: Enable --mem-usage for s390x
Atsushi Kumagai
kumagai-atsushi at mxc.nes.nec.co.jp
Mon Oct 27 21:34:33 PDT 2014
>On 10/27/14 at 03:57pm, Baoquan He wrote:
>> On 10/23/14 at 06:56am, Atsushi Kumagai wrote:
>> > >On Tue, 14 Oct 2014 07:19:13 +0000
>> > >Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp> wrote:
>> > >
>> > >[snip]
>> > >
>> > >>
>> > >> I understand why your patch works on s390x, so how about this way ?
>> > >>
>> > >> 1. Define "is_phys_addr()" for --mem-usage.
>> > >> 2. Implement is_phys_addr() using is_iomem_phys_addr() for s390x
>> > >> while x86_64 uses is_vmalloc_addr_x86_64().
>> > >> 3. Use is_phys_addr() instead of is_vmalloc_addr() in get_kcore_dump_loads().
>> > >
>> > >Hello Atsushi,
>> > >
>> > >Great, so let's do that.
>> > >
>> > >@Baoquan:
>> > >If you want to use the is_iomem_phys_addr() function also for x86,
>> > >you could perhaps add an additional patch.
>> >
>> > I noticed that is_vmalloc_addr_x86_64() can't be used as is_phys_addr()
>> > due to the "kaslr issue". I fixed it in the common path as below, but
>> > --mem-usage still has the same issue since initial() will be invoked
>> > after get_kcore_dump_loads().
>> >
>> > http://lists.infradead.org/pipermail/kexec/2014-October/012743.html
>> >
>> > I know it's so late, but I began to think the current implementation
>> > that invokes vaddr_to_paddr_XXX() before initial() is bad:
>> >
>> > show_mem_usage()
>> > + get_kcore_dump_loads()
>> > + process_dump_load()
>> > + vaddr_to_paddr_XXX()
>> > + initial()
>>
>> This is a bug. Seems that get_kcore_dump_loads() has to be called in
>> initial(). Since dumped vmcore need contains kernel text segment.
>> Without setting correct value for MODULES_VADDR, it will be equal to
>> __START_KERNEL_map, then calling is_vmalloc_addr() will filter kernel
>> text mapping segment too.
>>
>> Now it seems only one way to solve this, that is moving
>> get_kcore_dump_loads() into initial() just after
>> get_value_for_old_linux() is called.
>
>
>Hi Atsushi,
>
>Checking code again, I found with kaslr support we need move vmcoreinfo
>reading earlier to initialize the MODULES_VADDR, otherwise
>get_phys_base_x86_64() will be wrong. Since not initializing
>MODULES_VADDR explicitly its value is equal to __START_KERNEL_map, that
>means kernel text mapping segment is filtered by
>is_vmalloc_addr_x86_64().
>
>So could we move below code earlier?
Good catch, but...
>diff --git a/makedumpfile.c b/makedumpfile.c
>index b27ea1e..1dac19f 100644
>--- a/makedumpfile.c
>+++ b/makedumpfile.c
>@@ -3092,6 +3092,23 @@ initial(void)
> return FALSE;
> }
>
>+ /*
>+ * Get the debug information from /proc/vmcore.
>+ * NOTE: Don't move this code to the above, because the debugging
>+ * information token by -x/-i option is overwritten by vmcoreinfo
>+ * in /proc/vmcore. vmcoreinfo in /proc/vmcore is more reliable
>+ * than -x/-i option.
>+ */
please see above, this note means we have to keep the reading order
of vmcoreinfo, so the code will be like below.
I'll do it on the devel branch soon.
diff --git a/makedumpfile.c b/makedumpfile.c
index b27ea1e..3075809 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -3091,61 +3091,6 @@ initial(void)
MSG("Try `makedumpfile --help' for more information.\n");
return FALSE;
}
-
- if (info->flag_refiltering) {
- if (info->flag_elf_dumpfile) {
- MSG("'-E' option is disable, ");
- MSG("because %s is kdump compressed format.\n",
- info->name_memory);
- return FALSE;
- }
-
- if(info->flag_cyclic) {
- info->flag_cyclic = FALSE;
- MSG("Switched running mode from cyclic to non-cyclic,\n");
- MSG("because the cyclic mode doesn't support refiltering\n");
- MSG("kdump compressed format.\n");
- }
-
- info->phys_base = info->kh_memory->phys_base;
- info->max_dump_level |= info->kh_memory->dump_level;
-
- if (!initialize_bitmap_memory())
- return FALSE;
-
- } else if (info->flag_sadump) {
- if (info->flag_elf_dumpfile) {
- MSG("'-E' option is disable, ");
- MSG("because %s is sadump %s format.\n",
- info->name_memory, sadump_format_type_name());
- return FALSE;
- }
-
- if(info->flag_cyclic) {
- info->flag_cyclic = FALSE;
- MSG("Switched running mode from cyclic to non-cyclic,\n");
- MSG("because the cyclic mode doesn't support sadump format.\n");
- }
-
- set_page_size(sadump_page_size());
-
- if (!sadump_initialize_bitmap_memory())
- return FALSE;
-
- (void) sadump_set_timestamp(&info->timestamp);
-
- /*
- * NOTE: phys_base is never saved by sadump and so
- * must be computed in some way. We here choose the
- * way of looking at linux_banner. See
- * sadump_virt_phys_base(). The processing is
- * postponed until debug information becomes
- * available.
- */
-
- } else if (!get_phys_base())
- return FALSE;
-
/*
* Get the debug information for analysis from the vmcoreinfo file
*/
@@ -3206,6 +3151,60 @@ initial(void)
if (!get_value_for_old_linux())
return FALSE;
+ if (info->flag_refiltering) {
+ if (info->flag_elf_dumpfile) {
+ MSG("'-E' option is disable, ");
+ MSG("because %s is kdump compressed format.\n",
+ info->name_memory);
+ return FALSE;
+ }
+
+ if(info->flag_cyclic) {
+ info->flag_cyclic = FALSE;
+ MSG("Switched running mode from cyclic to non-cyclic,\n");
+ MSG("because the cyclic mode doesn't support refiltering\n");
+ MSG("kdump compressed format.\n");
+ }
+
+ info->phys_base = info->kh_memory->phys_base;
+ info->max_dump_level |= info->kh_memory->dump_level;
+
+ if (!initialize_bitmap_memory())
+ return FALSE;
+
+ } else if (info->flag_sadump) {
+ if (info->flag_elf_dumpfile) {
+ MSG("'-E' option is disable, ");
+ MSG("because %s is sadump %s format.\n",
+ info->name_memory, sadump_format_type_name());
+ return FALSE;
+ }
+
+ if(info->flag_cyclic) {
+ info->flag_cyclic = FALSE;
+ MSG("Switched running mode from cyclic to non-cyclic,\n");
+ MSG("because the cyclic mode doesn't support sadump format.\n");
+ }
+
+ set_page_size(sadump_page_size());
+
+ if (!sadump_initialize_bitmap_memory())
+ return FALSE;
+
+ (void) sadump_set_timestamp(&info->timestamp);
+
+ /*
+ * NOTE: phys_base is never saved by sadump and so
+ * must be computed in some way. We here choose the
+ * way of looking at linux_banner. See
+ * sadump_virt_phys_base(). The processing is
+ * postponed until debug information becomes
+ * available.
+ */
+
+ } else if (!get_phys_base())
+ return FALSE;
+
out:
if (!info->page_size) {
/*
Thanks,
Atsushi Kumagai
>+ if (has_vmcoreinfo()) {
>+ get_vmcoreinfo(&offset, &size);
>+ if (!read_vmcoreinfo_from_vmcore(offset, size, FALSE))
>+ return FALSE;
>+ debug_info = TRUE;
>+ }
>+
>+ if (!get_value_for_old_linux())
>+ return FALSE;
>+
> if (info->flag_refiltering) {
> if (info->flag_elf_dumpfile) {
> MSG("'-E' option is disable, ");
>@@ -3189,23 +3206,6 @@ initial(void)
> }
> }
>
>- /*
>- * Get the debug information from /proc/vmcore.
>- * NOTE: Don't move this code to the above, because the debugging
>- * information token by -x/-i option is overwritten by vmcoreinfo
>- * in /proc/vmcore. vmcoreinfo in /proc/vmcore is more reliable
>- * than -x/-i option.
>- */
>- if (has_vmcoreinfo()) {
>- get_vmcoreinfo(&offset, &size);
>- if (!read_vmcoreinfo_from_vmcore(offset, size, FALSE))
>- return FALSE;
>- debug_info = TRUE;
>- }
>-
>- if (!get_value_for_old_linux())
>- return FALSE;
>-
> out:
> if (!info->page_size) {
> /*
>
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