[PATCH] makedumpfile: ppc64: get vmalloc start address from vmcoreinfo
Aditya Gupta
adityag at linux.ibm.com
Mon Mar 18 02:00:08 PDT 2024
On 18/03/24 14:18, HAGIO KAZUHITO(萩尾 一仁) wrote:
> On 2024/03/18 17:26, Aditya Gupta wrote:
>> Hi,
>> The commit removing 'vmap_area_list' is now merged in Linux mainline tree.
>> commit: 55c49fee57af99f3c663e69dedc5b85e691bbe50
>> mm/vmalloc: remove vmap_area_list
> Applied with this commit id and the fix.
> https://github.com/makedumpfile/makedumpfile/commit/94241fd2feed059227a243618f2acc6aabf366e8
Thanks Kazu.
- Aditya Gupta
> Thanks,
> Kazu
>
>> Any comments on this patch ?
>>
>> Thanks,
>>
>> Aditya Gupta
>>
>> On 24/02/24 00:33, Aditya Gupta wrote:
>>> Below error was noticed when running makedumpfile on linux-next kernel
>>> crash (linux-next tag next-20240121):
>>>
>>> ...
>>> Checking for memory holes : [100.0 %] | readpage_elf: Attempt to
>>> read non-existent page at 0xc000000000000.
>>> [ 17.551718] kdump.sh[404]: readmem: type_addr: 0,
>>> addr:c00c000000000000, size:16384
>>> [ 17.551793] kdump.sh[404]: __exclude_unnecessary_pages: Can't
>>> read the buffer of struct page.
>>> [ 17.551864] kdump.sh[404]: create_2nd_bitmap: Can't exclude
>>> unnecessary pages.
>>> [ 17.562632] kdump.sh[404]: The kernel version is not supported.
>>> [ 17.562708] kdump.sh[404]: The makedumpfile operation may be
>>> incomplete.
>>> [ 17.562773] kdump.sh[404]: makedumpfile Failed.
>>> [ 17.564335] kdump[406]: saving vmcore failed, _exitcode:1
>>>
>>> Above error was due to 'vmap_area_list' and 'vmlist' symbols missing
>>> from the vmcore.
>>>
>>> 'vmap_area_list' was removed in the linux kernel with below commit:
>>>
>>> commit 378eb24a0658dd922b29524e0ce35c6c43f56cba
>>> mm/vmalloc: remove vmap_area_list
>>>
>>> Subsequently the commit also introduced 'VMALLOC_START' in vmcoreinfo to
>>> get base address of vmalloc area, instead of depending on
>>> 'vmap_area_list'
>>>
>>> Hence if 'VMALLOC_START' symbol is there in vmcoreinfo:
>>> 1. Set vmalloc_start based on 'VMALLOC_START'
>>> 2. Don't error if vmap_area_list/vmlist are not defined
>>>
>>> Reported-by: Sachin Sant <sachinp at linux.ibm.com>
>>> Signed-off-by: Aditya Gupta <adityag at linux.ibm.com>
>>> ---
>>> arch/ppc64.c | 19 +++++++++++++------
>>> makedumpfile.c | 3 ++-
>>> makedumpfile.h | 6 +++---
>>> 3 files changed, 18 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/arch/ppc64.c b/arch/ppc64.c
>>> index 96c357cb0335..bb62e2cd199a 100644
>>> --- a/arch/ppc64.c
>>> +++ b/arch/ppc64.c
>>> @@ -568,7 +568,9 @@ get_machdep_info_ppc64(void)
>>> /*
>>> * Get vmalloc_start value from either vmap_area_list or vmlist.
>>> */
>>> - if ((SYMBOL(vmap_area_list) != NOT_FOUND_SYMBOL)
>>> + if (NUMBER(vmalloc_start) != NOT_FOUND_SYMBOL) {
>>> + vmalloc_start = NUMBER(vmalloc_start);
>>> + } else if ((SYMBOL(vmap_area_list) != NOT_FOUND_SYMBOL)
>>> && (OFFSET(vmap_area.va_start) != NOT_FOUND_STRUCTURE)
>>> && (OFFSET(vmap_area.list) != NOT_FOUND_STRUCTURE)) {
>>> if (!readmem(VADDR, SYMBOL(vmap_area_list) +
>>> OFFSET(list_head.next),
>>> @@ -684,11 +686,16 @@ vaddr_to_paddr_ppc64(unsigned long vaddr)
>>> if ((SYMBOL(vmap_area_list) == NOT_FOUND_SYMBOL)
>>> || (OFFSET(vmap_area.va_start) == NOT_FOUND_STRUCTURE)
>>> || (OFFSET(vmap_area.list) == NOT_FOUND_STRUCTURE)) {
>>> - if ((SYMBOL(vmlist) == NOT_FOUND_SYMBOL)
>>> - || (OFFSET(vm_struct.addr) == NOT_FOUND_STRUCTURE)) {
>>> - ERRMSG("Can't get info for vmalloc translation.\n");
>>> - return NOT_PADDR;
>>> - }
>>> + /*
>>> + * Don't depend on vmap_area_list/vmlist if vmalloc_start is
>>> set in
>>> + * vmcoreinfo, in that case proceed without error
>>> + */
>>> + if (NUMBER(vmalloc_start) == NOT_FOUND_NUMBER)
>>> + if ((SYMBOL(vmlist) == NOT_FOUND_SYMBOL)
>>> + || (OFFSET(vm_struct.addr) == NOT_FOUND_STRUCTURE)) {
>>> + ERRMSG("Can't get info for vmalloc translation.\n");
>>> + return NOT_PADDR;
>>> + }
>>> }
>>> return ppc64_vtop_level4(vaddr);
>>> diff --git a/makedumpfile.c b/makedumpfile.c
>>> index b004b93fecb7..b6c63fad15f3 100644
>>> --- a/makedumpfile.c
>>> +++ b/makedumpfile.c
>>> @@ -2978,6 +2978,8 @@ read_vmcoreinfo(void)
>>> READ_NUMBER("PAGE_OFFLINE_MAPCOUNT_VALUE",
>>> PAGE_OFFLINE_MAPCOUNT_VALUE);
>>> READ_NUMBER("phys_base", phys_base);
>>> READ_NUMBER("KERNEL_IMAGE_SIZE", KERNEL_IMAGE_SIZE);
>>> +
>>> + READ_NUMBER_UNSIGNED("VMALLOC_START", vmalloc_start);
>>> #ifdef __aarch64__
>>> READ_NUMBER("VA_BITS", VA_BITS);
>>> READ_NUMBER("TCR_EL1_T1SZ", TCR_EL1_T1SZ);
>>> @@ -2989,7 +2991,6 @@ read_vmcoreinfo(void)
>>> READ_NUMBER("VA_BITS", va_bits);
>>> READ_NUMBER_UNSIGNED("phys_ram_base", phys_ram_base);
>>> READ_NUMBER_UNSIGNED("PAGE_OFFSET", page_offset);
>>> - READ_NUMBER_UNSIGNED("VMALLOC_START", vmalloc_start);
>>> READ_NUMBER_UNSIGNED("VMALLOC_END", vmalloc_end);
>>> READ_NUMBER_UNSIGNED("VMEMMAP_START", vmemmap_start);
>>> READ_NUMBER_UNSIGNED("VMEMMAP_END", vmemmap_end);
>>> diff --git a/makedumpfile.h b/makedumpfile.h
>>> index 59c83e1d9df3..4021c5af2a34 100644
>>> --- a/makedumpfile.h
>>> +++ b/makedumpfile.h
>>> @@ -541,8 +541,6 @@ do { \
>>> * The value of dependence on machine
>>> */
>>> #define PAGE_OFFSET (info->page_offset)
>>> -#define VMALLOC_START (info->vmalloc_start)
>>> -#define VMALLOC_END (info->vmalloc_end)
>>> #define VMEMMAP_START (info->vmemmap_start)
>>> #define VMEMMAP_END (info->vmemmap_end)
>>> #define PMASK (0x7ffffffffffff000UL)
>>> @@ -2262,6 +2260,9 @@ struct number_table {
>>> long HUGETLB_PAGE_DTOR;
>>> long phys_base;
>>> long KERNEL_IMAGE_SIZE;
>>> +
>>> + unsigned long vmalloc_start;
>>> +
>>> #ifdef __aarch64__
>>> long VA_BITS;
>>> long TCR_EL1_T1SZ;
>>> @@ -2272,7 +2273,6 @@ struct number_table {
>>> long va_bits;
>>> unsigned long phys_ram_base;
>>> unsigned long page_offset;
>>> - unsigned long vmalloc_start;
>>> unsigned long vmalloc_end;
>>> unsigned long vmemmap_start;
>>> unsigned long vmemmap_end;
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