On 04/14/2020 03:09 AM, HAGIO KAZUHITO(萩尾 一仁) wrote:
> Hi Pingfan,
>
>> -----Original Message-----
>> The crashed kernel passes usable RAM info through pt_loads[], but the
>> current code ignore this, and parse all sections below info->max_mapnr.
>> Refer to code in get_mm_sparsemem()
>> num_section = divideup(info->max_mapnr, PAGES_PER_SECTION());
>>
>> These ranges can include unwanted memory e.g. reserved-memory for crash
>> kernel, PMEM for fs-dax. Excluding them by setting mem_maps[section_nr]=NULL.
>
> hmm, I think that bitmap1 corresponds to pt_loads ranges, so even without
> the patch, only the ranges in pt_loads can be included in a dumpfile.
> Am I missing anything?
>
Check the code, and I think you are right.
Thanks,
Pingfan
> Thanks,
> Kazu
>
>>
>> Signed-off-by: Pingfan Liu <[email protected]>
>> ---
>> elf_info.c | 12 ++++++++++++
>> elf_info.h | 1 +
>> makedumpfile.c | 5 +++++
>> 3 files changed, 18 insertions(+)
>>
>> diff --git a/elf_info.c b/elf_info.c
>> index 7d72742..297c3e4 100644
>> --- a/elf_info.c
>> +++ b/elf_info.c
>> @@ -1302,3 +1302,15 @@ get_max_file_offset(void)
>> {
>> return max_file_offset;
>> }
>> +
>> +int phyaddr_in_pt_loads(unsigned long long phys_start)
>> +{
>> + struct pt_load_segment *pls;
>> +
>> + for (int i = 0; i < num_pt_loads; i++) {
>> + pls = &pt_loads[i];
>> + if (phys_start >= pls->phys_start && phys_start < pls->phys_end)
>> + return TRUE;
>> + }
>> + return FALSE;
>> +}
>> diff --git a/elf_info.h b/elf_info.h
>> index 934b608..f5bb07c 100644
>> --- a/elf_info.h
>> +++ b/elf_info.h
>> @@ -90,6 +90,7 @@ void get_eraseinfo(off_t *offset, unsigned long *size);
>> void set_eraseinfo(off_t offset, unsigned long size);
>>
>> off_t get_max_file_offset(void);
>> +int phyaddr_in_pt_loads(unsigned long long phys_start);
>>
>> #endif /* ELF_INFO_H */
>>
>> diff --git a/makedumpfile.c b/makedumpfile.c
>> index f5860a1..c0fa075 100644
>> --- a/makedumpfile.c
>> +++ b/makedumpfile.c
>> @@ -3556,8 +3556,13 @@ get_mm_sparsemem(void)
>> goto out;
>> }
>> for (section_nr = 0; section_nr < num_section; section_nr++) {
>> + unsigned long phys_start;
>> +
>> pfn_start = section_nr * PAGES_PER_SECTION();
>> pfn_end = pfn_start + PAGES_PER_SECTION();
>> + phys_start = pfn_start << PAGESHIFT();
>> + if (!phyaddr_in_pt_loads(phys_start))
>> + mem_maps[section_nr] = (unsigned long)NULL;
>> if (info->max_mapnr < pfn_end)
>> pfn_end = info->max_mapnr;
>> dump_mem_map(pfn_start, pfn_end, mem_maps[section_nr],
>> section_nr);
>> --
>> 2.7.5
>
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