9:10 a.m.
On Sun, Dec 4, 2016 at 6:05 AM, Rabin Vincent <rabin(a)rab.in> wrote:
On Sat, Dec 03, 2016 at 01:15:23PM -0800, Sagar Borikar wrote:
> > So the first error should be fixed properly before attempting "mod".
What
> > kernel version is this and what page size do to use?
>
> 4.4.20 kernel and page size is 16K
I'd only tested 4K pages before but I've now provisioned a QEMU Malta machine
with 16K pages. I've now sent a patch to the list which fixes the
definition of __PGD_ORDER. With only that patch, the pgd size errors
are gone and "mod" works for my 16K kernel/dump:
crash> sym -n swapper_pg_dir
80540000 (B) swapper_pg_dir
80544000 (B) invalid_pte_table
crash> sys
KERNEL: vmlinux-16k-unload
DUMPFILES: /var/tmp/ramdump_elf_wZxP65 [temporary ELF header]
rawdump-16k-unload
CPUS: 1
DATE: Sun Dec 4 14:46:08 2016
UPTIME: 00:00:21
LOAD AVERAGE: 0.31, 0.07, 0.02
TASKS: 54
NODENAME: buildroot
RELEASE: 4.4.27-dirty
VERSION: #12 SMP Sun Dec 4 14:45:32 CET 2016
MACHINE: mips (unknown Mhz)
MEMORY: 128 MB
PANIC: "Kernel panic - not syncing: Fatal exception"
crash> help -m | grep -A7 pagesize
pagesize: 16384
pageshift: 14
pagemask: ffffffffffffc000
pageoffset: 3fff
pgdir_shift: 26
ptrs_per_pgd: 64
ptrs_per_pte: 4096
stacksize: 16384
crash> mod
MODULE NAME SIZE OBJECT FILE
c01050c0 null_blk 5333 (not loaded) [CONFIG_KALLSYMS]
With the fixed __PGD_ORDER, PGD_ORDER gets the value zero and that is
correct for my kernel. __PGD_ORDER isn't used anywhere else that in
PGD_ORDER, so even your hack of forcing PGD_ORDER to zero would have
fixed "mod" for me.
So there could be some other additional problem in your case besides the
incorrect __PGD_ORDER. Could you please apply the fix and run crash
with the -d8 argument and post the full log? Thanks.
With your earlier patches, its same result as I was getting. i.e
please wait... (gathering module symbol data)
WARNING: cannot access vmalloc'd module memory
crash> mod
mod: cannot access vmalloc'd module memory
Here is detailed info of the help -m and mach output
flags: 1 (KSYMS_START)
[0/153]
kvbase: 80000000
identity_map_base: 80000000
pagesize: 16384
pageshift: 14
pagemask: ffffffffffffc000
pageoffset: 3fff
pgdir_shift: 26
ptrs_per_pgd: 64
ptrs_per_pte: 4096
stacksize: 16384
hz: 1000
memsize: 261865472 (0xf9bc000)
bits: 32
nr_irqs: 360
eframe_search: mips_eframe_search()
back_trace: mips_back_trace_cmd()
processor_speed: mips_processor_speed()
uvtop: mips_uvtop()
kvtop: mips_kvtop()
get_task_pgd: mips_get_task_pgd()
dump_irq: generic_dump_irq()
show_interrupts: generic_show_interrupts()
get_irq_affinity: generic_get_irq_affinity()
get_stack_frame: mips_get_stack_frame()
get_stackbase: generic_get_stackbase()
get_stacktop: generic_get_stacktop()
translate_pte: mips_translate_pte()
memory_size: generic_memory_size()
vmalloc_start: mips_vmalloc_start()
is_task_addr: mips_is_task_addr()
verify_symbol: mips_verify_symbol()
dis_filter: generic_dis_filter()
cmd_mach: mips_cmd_mach()
get_smp_cpus: mips_get_smp_cpus()
is_kvaddr: generic_is_kvaddr()
is_uvaddr: generic_is_uvaddr()
verify_paddr: generic_verify_paddr()
init_kernel_pgd: NULL
value_to_symbol: generic_machdep_value_to_symbol()
line_number_hooks: NULL
last_pgd_read: 82c30000
last_pmd_read: 0
last_ptbl_read: 3018000
pgd: 8a71b70
pmd: 0
ptbl: 8a75b78
section_size_bits: 26
max_physmem_bits: 32
sections_per_root: 0
machspec: 8696240
crash> mach
HZ: 1000
PAGE SIZE: 16384
_PAGE_PRESENT: 00000001
_PAGE_READ: 00000020
_PAGE_WRITE: 00000002
_PAGE_ACCESSED: 00000004
_PAGE_MODIFIED: 00000008
_PAGE_GLOBAL: 00000040
_PAGE_VALID: 00000080
_PAGE_NO_READ: 00000020
_PAGE_NO_EXEC: 00000010
_PAGE_DIRTY: 00000100
Please find the attached log with -d8 output.
Thanks
Sagar
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