Hi Kazu,
On Wed, Feb 28, 2024 at 04:51:28AM +0000, HAGIO KAZUHITO(萩尾 一仁) wrote:
> Hi Aditya,
>
> thanks for the patch.
>
> On 2024/02/24 4:03, 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@xxxxxxxxxxxxx>
> > Signed-off-by: Aditya Gupta <adityag@xxxxxxxxxxxxx>
> > ---
> > 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) {
>
> I will fix this NOT_FOUND_SYMBOL to NOT_FOUND_NUMBER when applying,
> otherwise makedumpfile will fail for a dumpfile without the
> corresponding kernel patch, correct?
>
> The patch looks good to me except for it. I will apply this with the
> kernel version in the commit log after the kernel patch gets merged.
Sure, thanks Kazu. I just ran it on an older version, it succeeds
collecting dump on 6.5.0 kernel somehow, though I agree with your
suggestion, it should have been NOT_FOUND_NUMBER. I will be more careful
about these things later.
Thanks,
Aditya Gupta
>
> Thanks,
> Kazu
>
>
> > + 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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