[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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