* [Makedumpfile PATCH V2] elf_info: fix file_size if segment is excluded
@ 2017-05-09 13:53 Pratyush Anand
2017-05-10 3:28 ` Xunlei Pang
0 siblings, 1 reply; 3+ messages in thread
From: Pratyush Anand @ 2017-05-09 13:53 UTC (permalink / raw)
To: ats-kumagai; +Cc: Pratyush Anand, dyoung, kexec, bhe
I received following on a specific x86_64 hp virtual machine while
executing `makedumpfile --mem-usage /proc/kcore`.
vtop4_x86_64: Can't get a valid pte.
readmem: Can't convert a virtual address(ffffffff88115860) to physical address.
readmem: type_addr: 0, addr:ffffffff88115860, size:128
get_nodes_online: Can't get the node online map.
With some debug print in vtop4_x86_64() I noticed that pte value is read
as 0, while crash reads the value correctly:
from makedumpfile:
vaddr=ffffffff88115860
page_dir=59eaff8
pml4=59ed067
pgd_paddr=59edff0
pgd_pte=59ee063
pmd_paddr=59ee200
pmd_pte=3642f063
pte_paddr=3642f8a8
pte=0
from crash
crash> vtop ffffffff88115860
VIRTUAL PHYSICAL
ffffffff88115860 5b15860
PML4 DIRECTORY: ffffffff87fea000
PAGE DIRECTORY: 59ed067
PUD: 59edff0 => 59ee063
PMD: 59ee200 => 3642f063
PTE: 3642f8a8 => 5b15163
PAGE: 5b15000
With some more debug prints in elf_info.c
Before calling exclude_segment()
LOAD (2)
phys_start : 100000
phys_end : dfffd000
virt_start : ffff8a5a40100000
virt_end : ffff8a5b1fffd000
file_offset: a5a40102000
file_size : dfefd000
exclude_segment() is called for Crash Kernel whose range is
2b000000-350fffff.
We see following after exclude_segment()
LOAD (2)
phys_start : 100000
phys_end : 2affffff
virt_start : ffff8a5a40100000
virt_end : ffff8a5a6affffff
file_offset: a5a40102000
file_size : dfefd000
LOAD (3)
phys_start : 35100000
phys_end : dfffd000
virt_start : ffff8a5a75100000
virt_end : ffff8a5b1fffd000
file_offset: a5a75102000
file_size : 0
Since file_size is calculated wrong therefore readpage_elf() does not
behave correctly.
This patch fixes above wrong behavior.
Signed-off-by: Pratyush Anand <panand@redhat.com>
---
v1->v2 : subtracted (end - start) from file_size as well
elf_info.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/elf_info.c b/elf_info.c
index 8e2437622141..5494c4dcbebe 100644
--- a/elf_info.c
+++ b/elf_info.c
@@ -826,9 +826,13 @@ static int exclude_segment(struct pt_load_segment **pt_loads,
temp_seg.virt_end = vend;
temp_seg.file_offset = (*pt_loads)[i].file_offset
+ temp_seg.virt_start - (*pt_loads)[i].virt_start;
+ temp_seg.file_size = temp_seg.phys_end
+ - temp_seg.phys_start;
(*pt_loads)[i].virt_end = kvstart - 1;
(*pt_loads)[i].phys_end = start - 1;
+ (*pt_loads)[i].file_size -= (temp_seg.file_size
+ + end - start);
tidx = i+1;
} else if (kvstart != vstart) {
--
2.9.3
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [Makedumpfile PATCH V2] elf_info: fix file_size if segment is excluded
2017-05-09 13:53 [Makedumpfile PATCH V2] elf_info: fix file_size if segment is excluded Pratyush Anand
@ 2017-05-10 3:28 ` Xunlei Pang
2017-05-10 4:43 ` Pratyush Anand
0 siblings, 1 reply; 3+ messages in thread
From: Xunlei Pang @ 2017-05-10 3:28 UTC (permalink / raw)
To: Pratyush Anand, ats-kumagai; +Cc: kexec, dyoung, bhe
On 05/09/2017 at 09:53 PM, Pratyush Anand wrote:
> I received following on a specific x86_64 hp virtual machine while
> executing `makedumpfile --mem-usage /proc/kcore`.
>
> vtop4_x86_64: Can't get a valid pte.
> readmem: Can't convert a virtual address(ffffffff88115860) to physical address.
> readmem: type_addr: 0, addr:ffffffff88115860, size:128
> get_nodes_online: Can't get the node online map.
>
> With some debug print in vtop4_x86_64() I noticed that pte value is read
> as 0, while crash reads the value correctly:
>
> from makedumpfile:
> vaddr=ffffffff88115860
> page_dir=59eaff8
> pml4=59ed067
> pgd_paddr=59edff0
> pgd_pte=59ee063
> pmd_paddr=59ee200
> pmd_pte=3642f063
> pte_paddr=3642f8a8
> pte=0
>
> from crash
> crash> vtop ffffffff88115860
> VIRTUAL PHYSICAL
> ffffffff88115860 5b15860
>
> PML4 DIRECTORY: ffffffff87fea000
> PAGE DIRECTORY: 59ed067
> PUD: 59edff0 => 59ee063
> PMD: 59ee200 => 3642f063
> PTE: 3642f8a8 => 5b15163
> PAGE: 5b15000
>
> With some more debug prints in elf_info.c
>
> Before calling exclude_segment()
>
> LOAD (2)
> phys_start : 100000
> phys_end : dfffd000
> virt_start : ffff8a5a40100000
> virt_end : ffff8a5b1fffd000
> file_offset: a5a40102000
> file_size : dfefd000
>
> exclude_segment() is called for Crash Kernel whose range is
> 2b000000-350fffff.
>
> We see following after exclude_segment()
>
> LOAD (2)
> phys_start : 100000
> phys_end : 2affffff
> virt_start : ffff8a5a40100000
> virt_end : ffff8a5a6affffff
> file_offset: a5a40102000
> file_size : dfefd000
> LOAD (3)
> phys_start : 35100000
> phys_end : dfffd000
> virt_start : ffff8a5a75100000
> virt_end : ffff8a5b1fffd000
> file_offset: a5a75102000
> file_size : 0
>
> Since file_size is calculated wrong therefore readpage_elf() does not
> behave correctly.
>
> This patch fixes above wrong behavior.
>
> Signed-off-by: Pratyush Anand <panand@redhat.com>
> ---
> v1->v2 : subtracted (end - start) from file_size as well
>
> elf_info.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/elf_info.c b/elf_info.c
> index 8e2437622141..5494c4dcbebe 100644
> --- a/elf_info.c
> +++ b/elf_info.c
> @@ -826,9 +826,13 @@ static int exclude_segment(struct pt_load_segment **pt_loads,
> temp_seg.virt_end = vend;
> temp_seg.file_offset = (*pt_loads)[i].file_offset
> + temp_seg.virt_start - (*pt_loads)[i].virt_start;
> + temp_seg.file_size = temp_seg.phys_end
> + - temp_seg.phys_start;
>
> (*pt_loads)[i].virt_end = kvstart - 1;
> (*pt_loads)[i].phys_end = start - 1;
> + (*pt_loads)[i].file_size -= (temp_seg.file_size
> + + end - start);
Hi Pratyush,
Don't we need to move the "(*pt_loads)[i].file_size" minus "(end - start)" down
to the tail of "if (kvstart < vend && kvend > vstart)" condition for all cases?
Regards,
Xunlei
>
> tidx = i+1;
> } else if (kvstart != vstart) {
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Makedumpfile PATCH V2] elf_info: fix file_size if segment is excluded
2017-05-10 3:28 ` Xunlei Pang
@ 2017-05-10 4:43 ` Pratyush Anand
0 siblings, 0 replies; 3+ messages in thread
From: Pratyush Anand @ 2017-05-10 4:43 UTC (permalink / raw)
To: xlpang, ats-kumagai; +Cc: kexec, dyoung, bhe
On Wednesday 10 May 2017 08:58 AM, Xunlei Pang wrote:
>> + (*pt_loads)[i].file_size -= (temp_seg.file_size
>> + + end - start);
> Hi Pratyush,
>
> Don't we need to move the "(*pt_loads)[i].file_size" minus "(end - start)" down
> to the tail of "if (kvstart < vend && kvend > vstart)" condition for all cases?
Yes..sent v3.
Thanks for review.
~Pratyush
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^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-05-09 13:53 [Makedumpfile PATCH V2] elf_info: fix file_size if segment is excluded Pratyush Anand
2017-05-10 3:28 ` Xunlei Pang
2017-05-10 4:43 ` Pratyush Anand
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