[PATCH] kexec-tools: Read always one vmcoreinfo file
Petr Tesarik
ptesarik at suse.cz
Mon Jul 23 09:30:55 EDT 2012
Dne Po 23. července 2012 14:56:07 Petr Tesarik napsal(a):
> Dne Čt 5. července 2012 14:16:35 Daniel Kiper napsal(a):
> > vmcoreinfo file could exists under /sys/kernel (valid on baremetal only)
> > and/or under /sys/hypervisor (valid when Xen dom0 is running).
> > Read only one of them. It means that only one PT_NOTE will be
> > always created. Remove extra code for second PT_NOTE creation.
>
> Hi Daniel,
>
> are you absolutely sure this is the right thing to do? IIUC these two
> VMCORINFO notes are very different. The one from /sys/kernel/vmcoreinfo
> describes the Dom0 kernel (type 'VMCOREINFO'), while the one from
> /sys/hypervisor describes the Xen hypervisor (type 'XEN_VMCOREINFO'). If
> you keep only the hypervisor note, then e.g. makedumpfile won't be able to
> use dumplevel greater than 1, nor will it be able to extract the log
> buffer.
I've just verified this, and I'm confident we have to keep both notes in the
dump file. Simon, please revert Daniel's patch to avoid regressions.
I'm attaching a sample VMCOREINFO_XEN and VMCOREINFO to demonstrate the
difference. Note that the VMCOREINFO_XEN note is actually too big, because Xen
doesn't bother to maintain the correct note size in the note header, so it
always spans a complete page minus sizeof(Elf64_Nhdr)...
Regards,
Petr Tesarik
> Petr Tesarik
> SUSE Linux
>
> > Signed-off-by: Daniel Kiper <daniel.kiper at oracle.com>
> > ---
> >
> > kexec/crashdump-elf.c | 33 +++++++--------------------------
> > 1 files changed, 7 insertions(+), 26 deletions(-)
> >
> > diff --git a/kexec/crashdump-elf.c b/kexec/crashdump-elf.c
> > index 8d82db9..ec66548 100644
> > --- a/kexec/crashdump-elf.c
> > +++ b/kexec/crashdump-elf.c
> > @@ -40,8 +40,6 @@ int FUNC(struct kexec_info *info,
> >
> > uint64_t notes_addr, notes_len;
> > uint64_t vmcoreinfo_addr, vmcoreinfo_len;
> > int has_vmcoreinfo = 0;
> >
> > - uint64_t vmcoreinfo_addr_xen, vmcoreinfo_len_xen;
> > - int has_vmcoreinfo_xen = 0;
> >
> > int (*get_note_info)(int cpu, uint64_t *addr, uint64_t *len);
> >
> > if (xen_present())
> >
> > @@ -53,16 +51,14 @@ int FUNC(struct kexec_info *info,
> >
> > return -1;
> >
> > }
> >
> > - if (get_kernel_vmcoreinfo(&vmcoreinfo_addr, &vmcoreinfo_len) == 0) {
> > - has_vmcoreinfo = 1;
> > - }
> > -
> > - if (xen_present() &&
> > - get_xen_vmcoreinfo(&vmcoreinfo_addr_xen, &vmcoreinfo_len_xen) ==
0)
> > { - has_vmcoreinfo_xen = 1;
> > - }
> > + if (xen_present()) {
> > + if (!get_xen_vmcoreinfo(&vmcoreinfo_addr, &vmcoreinfo_len))
> > + has_vmcoreinfo = 1;
> > + } else
> > + if (!get_kernel_vmcoreinfo(&vmcoreinfo_addr, &vmcoreinfo_len))
> > + has_vmcoreinfo = 1;
> >
> > - sz = sizeof(EHDR) + (nr_cpus + has_vmcoreinfo + has_vmcoreinfo_xen)
*
> > sizeof(PHDR) + + sz = sizeof(EHDR) + (nr_cpus + has_vmcoreinfo) *
> > sizeof(PHDR) +
> >
> > ranges * sizeof(PHDR);
> >
> > /*
> >
> > @@ -179,21 +175,6 @@ int FUNC(struct kexec_info *info,
> >
> > dbgprintf_phdr("vmcoreinfo header", phdr);
> >
> > }
> >
> > - if (has_vmcoreinfo_xen) {
> > - phdr = (PHDR *) bufp;
> > - bufp += sizeof(PHDR);
> > - phdr->p_type = PT_NOTE;
> > - phdr->p_flags = 0;
> > - phdr->p_offset = phdr->p_paddr = vmcoreinfo_addr_xen;
> > - phdr->p_vaddr = 0;
> > - phdr->p_filesz = phdr->p_memsz = vmcoreinfo_len_xen;
> > - /* Do we need any alignment of segments? */
> > - phdr->p_align = 0;
> > -
> > - (elf->e_phnum)++;
> > - dbgprintf_phdr("vmcoreinfo_xen header", phdr);
> > - }
> > -
> >
> > /* Setup an PT_LOAD type program header for the region where
> >
> > * Kernel is mapped if elf_info->kern_size is non-zero.
> > */
>
> _______________________________________________
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> http://lists.infradead.org/mailman/listinfo/kexec
-------------- next part --------------
PAGESIZE=4096
SYMBOL(domain_list)=ffff82c48029e0f0
SYMBOL(frame_table)=ffff82c48020d908
SYMBOL(max_page)=ffff82c4802c1a68
SIZE(page_info)=32
SIZE(domain)=5504
OFFSET(page_info.count_info)=8
OFFSET(page_info._domain)=24
OFFSET(domain.domain_id)=0
OFFSET(domain.next_in_list)=96
SYMBOL(dom_xen)=ffff82c4802c1a78
SYMBOL(dom_io)=ffff82c4802c1a80
SYMBOL(pgd_l4)=ffff82c480294000
-------------- next part --------------
OSRELEASE=3.0.34-0.7-xen
PAGESIZE=4096
SYMBOL(init_uts_ns)=ffffffff806b2fc0
SYMBOL(node_online_map)=ffffffff8070e968
SYMBOL(swapper_pg_dir)=ffffffff80783000
SYMBOL(_stext)=ffffffff80004000
SYMBOL(vmlist)=ffffffff8082ea40
SYMBOL(mem_map)=ffffffff8082e950
SYMBOL(contig_page_data)=ffffffff80700f80
SIZE(page)=56
SIZE(pglist_data)=6912
SIZE(zone)=1664
SIZE(free_area)=88
SIZE(list_head)=16
SIZE(nodemask_t)=8
OFFSET(page.flags)=0
OFFSET(page._count)=8
OFFSET(page.mapping)=24
OFFSET(page.lru)=40
OFFSET(pglist_data.node_zones)=0
OFFSET(pglist_data.nr_zones)=6744
OFFSET(pglist_data.node_mem_map)=6752
OFFSET(pglist_data.node_start_pfn)=6768
OFFSET(pglist_data.node_spanned_pages)=6784
OFFSET(pglist_data.node_id)=6792
OFFSET(zone.free_area)=88
OFFSET(zone.vm_stat)=1304
OFFSET(zone.spanned_pages)=1576
OFFSET(free_area.free_list)=0
OFFSET(list_head.next)=0
OFFSET(list_head.prev)=8
OFFSET(vm_struct.addr)=8
LENGTH(zone.free_area)=11
SYMBOL(log_buf)=ffffffff806b8470
SYMBOL(log_end)=ffffffff80796ac0
SYMBOL(log_buf_len)=ffffffff806b8464
SYMBOL(logged_chars)=ffffffff807d6bc0
LENGTH(free_area.free_list)=5
NUMBER(NR_FREE_PAGES)=0
NUMBER(PG_lru)=6
NUMBER(PG_private)=12
NUMBER(PG_head)=16
NUMBER(PG_swapcache)=18
SYMBOL(init_level4_pgt)=ffffffff80783000
CRASHTIME=1341922380
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