On Tuesday 16 May 2017 07:35 AM, Atsushi Kumagai wrote:
>> Hi Atsushi,
>>
>> Thanks for the testing.
>>
>> On Wednesday 10 May 2017 01:37 PM, Atsushi Kumagai wrote:
>>>> Hi Atsushi,
>>>>
>>>> On Friday 28 April 2017 12:22 PM, Atsushi Kumagai wrote:
>>>>> Hello Pratyush,
>>>>>
>>>>> Thanks for your report, I have received this.
>>>>> I'm on vacation until Mar 8, I'll review it when I return from vacation.
>>>>
>>>> Any further comment on it?
>>>> Otherwise, I will send a v2 after accommodating concern from Xunlei.
>>>
>>> Unfortunately, it doesn't seem like I can make time anymore for review this week,
>>> but at least this patch doesn't seem to work in my environment (linux 4.8 without kaslr).
>>> Do you have any ideas ?
>>
>> I see, why it would have caused. I have not tested this case, but I hope my v2
>> should not have this issue.
>
> Umm, v2 still doesn't work in my environment...
> It seems that I have to investigate this deeper.
Hummm, I thought we would see file_vmcoreinfo as NULL in
get_kaslr_offset_x86_64() in your case. However, it's not true.
I think, it will have to be initialized with NULL in main().
Can you please try following fixup on top of this series:
diff --git a/makedumpfile.c b/makedumpfile.c
index 57235690569e..0fd485ccd45d 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -11076,6 +11076,7 @@ main(int argc, char *argv[])
strerror(errno));
goto out;
}
+ info->file_vmcoreinfo = NULL;
info->fd_vmlinux = -1;
info->fd_xen_syms = -1;
info->fd_memory = -1;
Thanks for testing it thoroughly.
~Pratyush
>
> $ cat scrub.conf
> [vmlinux]
> erase modules size 50
> $
>
> (gdb) r -cd31 -x vmlinux --config scrub.conf vmcore dumpfile.cd31
> Starting program: /work/kdump_utils/makedumpfile/makedumpfile -cd31 -x vmlinux --config scrub.conf vmcore dumpfile.cd31
> warning: no loadable sections found in added symbol-file system-supplied DSO at 0x7ffff7ffd000
> [Thread debugging using libthread_db enabled]
>
> Program received signal SIGSEGV, Segmentation fault.
> 0x000000308366ee0d in fseek () from /lib64/libc.so.6
> Missing separate debuginfos, use: debuginfo-install bzip2-libs-1.0.5-7.el6_0.x86_64 elfutils-libelf-0.152-1.el6.x86_64 elfutils-libs-0.152-1.el6.x86_64 glibc-2.12-1.132.el6.x86_64 libgcc-4.4.7-4.el6.x86_64 libstdc++-4.4.7-4.el6.x86_64 snappy-1.1.0-1.el6.x86_64 xz-libs-4.999.9-0.3.beta.20091007git.el6.x86_64 zlib-1.2.3-29.el6.x86_64
> (gdb) bt
> #0 0x000000308366ee0d in fseek () from /lib64/libc.so.6
> #1 0x0000000000420937 in get_kaslr_offset_x86_64 (vaddr=18446744071589596288) at arch/x86_64.c:43
> #2 0x0000000000414310 in resolve_config_entry (ce=0x701370, base_vaddr=<value optimized out>, base_struct_name=0x0) at erase_info.c:1091
> #3 0x0000000000415a89 in get_config_symbol_addr (filter_symbol=0x701370, size_symbol=0x701430) at erase_info.c:1264
> #4 update_filter_info (filter_symbol=0x701370, size_symbol=0x701430) at erase_info.c:1579
> #5 0x0000000000416543 in process_config (name_config=<value optimized out>) at erase_info.c:1789
> #6 process_config_file (name_config=<value optimized out>) at erase_info.c:1862
> #7 0x0000000000417c57 in gather_filter_info () at erase_info.c:2356
> #8 0x0000000000443e5b in create_dumpfile () at makedumpfile.c:9870
> #9 0x00000000004457ae in main (argc=<value optimized out>, argv=<value optimized out>) at makedumpfile.c:11349
> (gdb)
>
> Thanks,
> Atsushi Kuamgai
>
>> ~Pratyush
>>>
>>>
>>> Program received signal SIGSEGV, Segmentation fault.
>>> 0x00007ffff6be49f5 in fseek () from /lib64/libc.so.6
>>> Missing separate debuginfos, use: debuginfo-install bzip2-libs-1.0.6-13.el7.x86_64 elfutils-libelf-0.163-3.el7.x86_64
>> elfutils-libs-0.163-3.el7.x86_64 glibc-2.17-105.el7.x86_64 libgcc-4.8.5-4.el7.x86_64 libstdc++-4.8.5-4.el7.x86_64
>> snappy-1.1.0-3.el7.x86_64 xz-libs-5.1.2-12alpha.el7.x86_64 zlib-1.2.7-15.el7.x86_64
>>> (gdb) bt
>>> #0 0x00007ffff6be49f5 in fseek () from /lib64/libc.so.6
>>> #1 0x0000000000429d38 in read_vmcoreinfo_symbol (str_symbol=0x44cb0c "SYMBOL(_stext)=") at makedumpfile.c:2384
>>> #2 0x000000000042097a in get_kaslr_offset_x86_64 (vaddr=18446744071589596288) at arch/x86_64.c:45
>>> #3 0x0000000000414310 in resolve_config_entry (ce=0x701370, base_vaddr=<optimized out>, base_struct_name=0x0)
>>> at erase_info.c:1091
>>> #4 0x0000000000415a89 in get_config_symbol_addr (base_struct_name=0x0, base_vaddr=0, ce=0x701370) at erase_info.c:1264
>>> #5 update_filter_info (filter_symbol=0x701370, size_symbol=0x701430) at erase_info.c:1579
>>> #6 0x0000000000416543 in process_config (config=<optimized out>) at erase_info.c:1789
>>> #7 process_config_file (name_config=<optimized out>) at erase_info.c:1862
>>> #8 0x0000000000417c57 in gather_filter_info () at erase_info.c:2356
>>> #9 0x0000000000443ccb in create_dumpfile () at makedumpfile.c:9863
>>> #10 0x000000000044561e in main (argc=<optimized out>, argv=<optimized out>) at makedumpfile.c:11342
>>> (gdb)
>>>
>>>
>>> Thanks,
>>> Atsushi Kumagai
>>>
>>>> ~Pratyush
>>>>
>>>>
>>>>>
>>>>> Thanks,
>>>>> Atsushi Kumagai
>>>>>
>>>>>> Hi All,
>>>>>>
>>>>>> We came across another failure in makedumpfile when kaslr is enabled. This
>>>>>> failure occurs when we try re-filtering. We try to erase some symbol from a
>>>>>> dumpfile which was copied/compressed from /proc/vmcore using makedumpfile.
>>>>>>
>>>>>> We have very limited symbol information in vmcoreinfo. So symbols to be
>>>>>> erased may not be available in vmcoreinfo and we look for it in vmlinux.
>>>>>> However, symbol address from vmlinux is a static address which differs
>>>>> >from run time address with KASLR_OFFSET. Therefore, reading any "virtual
>>>>>> address of vmlinux" from vmcore is not possible.
>>>>>>
>>>>>> These patches finds runtime KASLR offset and then calculates run time
>>>>>> address of symbols read from vmlinux.
>>>>>>
>>>>>> Since, I am not an expert of x86, and these patches touch x86 part of
>>>>>> makedumpfile, therefore I have CCed x86 experts. Please, provide your
>>>>>> review comment and let me know if you think there could have been a better
>>>>>> way to resolve this issue.
>>>>>>
>>>>>> thanks
>>>>>>
>>>>>> ~Pratyush
>>>>>>
>>>>>> Pratyush Anand (2):
>>>>>> makedumpfile: add runtime kaslr offset if it exists
>>>>>> x86_64: calculate page_offset in case of re-filtering
>>>>>>
>>>>>> arch/x86_64.c | 45 +++++++++++++++++++++++++++++++++++++++++++--
>>>>>> erase_info.c | 1 +
>>>>>> makedumpfile.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
>>>>>> makedumpfile.h | 15 +++++++++++++++
>>>>>> 4 files changed, 103 insertions(+), 2 deletions(-)
>>>>>>
>>>>>> --
>>>>>> 2.9.3
>>>>>
>>>
>>>
>>>
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