Re: gdb/scripts: Module symbol search paths
On 14/03/16 10:55, Jan Kiszka wrote:
> On 2016-03-14 11:48, Kieran Bingham wrote:
>> On 14/03/16 10:36, Jan Kiszka wrote:
>>> Hi Kieran,
>>>
>>> On 2016-03-14 11:20, Kieran Bingham wrote:
Hi Jan,
Whilst testing the modules update patch you sent, I discovered (due to
having rebased to v4.5) that the module search path will end up picking
an incorrect version of the .ko file if an earlier version exists.:
(gdb) lx-symbols /opt/root/ubuntu-vivid.x86_64
loading vmlinux
(gdb) c
Continuing.
< load module helloworld.ko on target >
scanning for modules in /opt/root/ubuntu-vivid.x86_64
loading @0xa000:
/opt/root/ubuntu-vivid.x86_64/lib/modules/4.4.0+/extra/helloworld.ko
Looking at the filesystem layout:
kbingham@CookieMonster:~$ sudo find /opt/root/ubuntu-vivid.x86_64/ -name
helloworld.ko
/opt/root/ubuntu-vivid.x86_64/lib/modules/4.4.0+/extra/helloworld.ko
/opt/root/ubuntu-vivid.x86_64/lib/modules/4.5.0+/extra/helloworld.ko
>>>
>>> If there are multiple sets of modules underneath a path, you have to be
>>> more precise, /opt/root/ubuntu-vivid.x86_64/lib/modules/4.5.0+ in this case.
>>>
Unfortunately I can't see any reference to a vfs path in:
print $lx_module("helloworld")
So we can't retrieve the exact path location from the kernel information
Have you experienced this issue?
>>>
>>> No, because I'm always using lx-symbols against the build output, not
>>> against installed modules. But even then, see above, I don't see a
>>> problem is the path is properly specified.
>>>
>>
>> Ok, I see. I guess it's just a different use-case. ST had this factored
>> out so that the user did not have to do much other than specify the root
>> path. And in fact, the 'user' didn't do this as it was pre-set.
>>
>> I had even toyed with the idea that we could parse the commandline - and
>> if we detect an nfsroot, automatically provide that on the search path.
>>
>> Perhaps we'll put this on the to-think-about stack for now then on this
>> side :)
>>
>> Specifying the full path to modules isn't an unreasonable solution IMO,
>> so it will just come down to a user-experience thing. The automatic
>> detection could just be classed as a nice feature for the future perhaps.
>
> If you wanna do version matching, you could parse the module header and
> filter out everything that's incompatible. But then I'm afraid of the
> loading time...
Interesting alternative. I guess this parsing would only occur on files
after a filename match, so I don't see it as being too intrusive.
Perhaps something to test and measure later, and would need testing on a
large number of modules (with a large number of false positives to match
against).
--
Kieran
>
> Jan
>
Re: gdb/scripts: Module symbol search paths
On 14/03/16 10:55, Jan Kiszka wrote:
> On 2016-03-14 11:48, Kieran Bingham wrote:
>> On 14/03/16 10:36, Jan Kiszka wrote:
>>> Hi Kieran,
>>>
>>> On 2016-03-14 11:20, Kieran Bingham wrote:
Hi Jan,
Whilst testing the modules update patch you sent, I discovered (due to
having rebased to v4.5) that the module search path will end up picking
an incorrect version of the .ko file if an earlier version exists.:
(gdb) lx-symbols /opt/root/ubuntu-vivid.x86_64
loading vmlinux
(gdb) c
Continuing.
< load module helloworld.ko on target >
scanning for modules in /opt/root/ubuntu-vivid.x86_64
loading @0xa000:
/opt/root/ubuntu-vivid.x86_64/lib/modules/4.4.0+/extra/helloworld.ko
Looking at the filesystem layout:
kbingham@CookieMonster:~$ sudo find /opt/root/ubuntu-vivid.x86_64/ -name
helloworld.ko
/opt/root/ubuntu-vivid.x86_64/lib/modules/4.4.0+/extra/helloworld.ko
/opt/root/ubuntu-vivid.x86_64/lib/modules/4.5.0+/extra/helloworld.ko
>>>
>>> If there are multiple sets of modules underneath a path, you have to be
>>> more precise, /opt/root/ubuntu-vivid.x86_64/lib/modules/4.5.0+ in this case.
>>>
Unfortunately I can't see any reference to a vfs path in:
print $lx_module("helloworld")
So we can't retrieve the exact path location from the kernel information
Have you experienced this issue?
>>>
>>> No, because I'm always using lx-symbols against the build output, not
>>> against installed modules. But even then, see above, I don't see a
>>> problem is the path is properly specified.
>>>
>>
>> Ok, I see. I guess it's just a different use-case. ST had this factored
>> out so that the user did not have to do much other than specify the root
>> path. And in fact, the 'user' didn't do this as it was pre-set.
>>
>> I had even toyed with the idea that we could parse the commandline - and
>> if we detect an nfsroot, automatically provide that on the search path.
>>
>> Perhaps we'll put this on the to-think-about stack for now then on this
>> side :)
>>
>> Specifying the full path to modules isn't an unreasonable solution IMO,
>> so it will just come down to a user-experience thing. The automatic
>> detection could just be classed as a nice feature for the future perhaps.
>
> If you wanna do version matching, you could parse the module header and
> filter out everything that's incompatible. But then I'm afraid of the
> loading time...
Interesting alternative. I guess this parsing would only occur on files
after a filename match, so I don't see it as being too intrusive.
Perhaps something to test and measure later, and would need testing on a
large number of modules (with a large number of false positives to match
against).
--
Kieran
>
> Jan
>
Re: gdb/scripts: Module symbol search paths
On 2016-03-14 11:48, Kieran Bingham wrote:
> On 14/03/16 10:36, Jan Kiszka wrote:
>> Hi Kieran,
>>
>> On 2016-03-14 11:20, Kieran Bingham wrote:
>>> Hi Jan,
>>>
>>> Whilst testing the modules update patch you sent, I discovered (due to
>>> having rebased to v4.5) that the module search path will end up picking
>>> an incorrect version of the .ko file if an earlier version exists.:
>>>
>>>
>>> (gdb) lx-symbols /opt/root/ubuntu-vivid.x86_64
>>> loading vmlinux
>>> (gdb) c
>>> Continuing.
>>> < load module helloworld.ko on target >
>>> scanning for modules in /opt/root/ubuntu-vivid.x86_64
>>> loading @0xa000:
>>> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.4.0+/extra/helloworld.ko
>>>
>>> Looking at the filesystem layout:
>>>
>>> kbingham@CookieMonster:~$ sudo find /opt/root/ubuntu-vivid.x86_64/ -name
>>> helloworld.ko
>>> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.4.0+/extra/helloworld.ko
>>> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.5.0+/extra/helloworld.ko
>>>
>>
>> If there are multiple sets of modules underneath a path, you have to be
>> more precise, /opt/root/ubuntu-vivid.x86_64/lib/modules/4.5.0+ in this case.
>>
>>>
>>> Unfortunately I can't see any reference to a vfs path in:
>>> print $lx_module("helloworld")
>>>
>>> So we can't retrieve the exact path location from the kernel information
>>> Have you experienced this issue?
>>
>> No, because I'm always using lx-symbols against the build output, not
>> against installed modules. But even then, see above, I don't see a
>> problem is the path is properly specified.
>>
>
> Ok, I see. I guess it's just a different use-case. ST had this factored
> out so that the user did not have to do much other than specify the root
> path. And in fact, the 'user' didn't do this as it was pre-set.
>
> I had even toyed with the idea that we could parse the commandline - and
> if we detect an nfsroot, automatically provide that on the search path.
>
> Perhaps we'll put this on the to-think-about stack for now then on this
> side :)
>
> Specifying the full path to modules isn't an unreasonable solution IMO,
> so it will just come down to a user-experience thing. The automatic
> detection could just be classed as a nice feature for the future perhaps.
If you wanna do version matching, you could parse the module header and
filter out everything that's incompatible. But then I'm afraid of the
loading time...
Jan
--
Siemens AG, Corporate Technology, CT RDA ITP SES-DE
Corporate Competence Center Embedded Linux
Re: gdb/scripts: Module symbol search paths
On 2016-03-14 11:48, Kieran Bingham wrote:
> On 14/03/16 10:36, Jan Kiszka wrote:
>> Hi Kieran,
>>
>> On 2016-03-14 11:20, Kieran Bingham wrote:
>>> Hi Jan,
>>>
>>> Whilst testing the modules update patch you sent, I discovered (due to
>>> having rebased to v4.5) that the module search path will end up picking
>>> an incorrect version of the .ko file if an earlier version exists.:
>>>
>>>
>>> (gdb) lx-symbols /opt/root/ubuntu-vivid.x86_64
>>> loading vmlinux
>>> (gdb) c
>>> Continuing.
>>> < load module helloworld.ko on target >
>>> scanning for modules in /opt/root/ubuntu-vivid.x86_64
>>> loading @0xa000:
>>> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.4.0+/extra/helloworld.ko
>>>
>>> Looking at the filesystem layout:
>>>
>>> kbingham@CookieMonster:~$ sudo find /opt/root/ubuntu-vivid.x86_64/ -name
>>> helloworld.ko
>>> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.4.0+/extra/helloworld.ko
>>> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.5.0+/extra/helloworld.ko
>>>
>>
>> If there are multiple sets of modules underneath a path, you have to be
>> more precise, /opt/root/ubuntu-vivid.x86_64/lib/modules/4.5.0+ in this case.
>>
>>>
>>> Unfortunately I can't see any reference to a vfs path in:
>>> print $lx_module("helloworld")
>>>
>>> So we can't retrieve the exact path location from the kernel information
>>> Have you experienced this issue?
>>
>> No, because I'm always using lx-symbols against the build output, not
>> against installed modules. But even then, see above, I don't see a
>> problem is the path is properly specified.
>>
>
> Ok, I see. I guess it's just a different use-case. ST had this factored
> out so that the user did not have to do much other than specify the root
> path. And in fact, the 'user' didn't do this as it was pre-set.
>
> I had even toyed with the idea that we could parse the commandline - and
> if we detect an nfsroot, automatically provide that on the search path.
>
> Perhaps we'll put this on the to-think-about stack for now then on this
> side :)
>
> Specifying the full path to modules isn't an unreasonable solution IMO,
> so it will just come down to a user-experience thing. The automatic
> detection could just be classed as a nice feature for the future perhaps.
If you wanna do version matching, you could parse the module header and
filter out everything that's incompatible. But then I'm afraid of the
loading time...
Jan
--
Siemens AG, Corporate Technology, CT RDA ITP SES-DE
Corporate Competence Center Embedded Linux
Re: gdb/scripts: Module symbol search paths
On 14/03/16 10:36, Jan Kiszka wrote:
> Hi Kieran,
>
> On 2016-03-14 11:20, Kieran Bingham wrote:
>> Hi Jan,
>>
>> Whilst testing the modules update patch you sent, I discovered (due to
>> having rebased to v4.5) that the module search path will end up picking
>> an incorrect version of the .ko file if an earlier version exists.:
>>
>>
>> (gdb) lx-symbols /opt/root/ubuntu-vivid.x86_64
>> loading vmlinux
>> (gdb) c
>> Continuing.
>> < load module helloworld.ko on target >
>> scanning for modules in /opt/root/ubuntu-vivid.x86_64
>> loading @0xa000:
>> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.4.0+/extra/helloworld.ko
>>
>> Looking at the filesystem layout:
>>
>> kbingham@CookieMonster:~$ sudo find /opt/root/ubuntu-vivid.x86_64/ -name
>> helloworld.ko
>> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.4.0+/extra/helloworld.ko
>> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.5.0+/extra/helloworld.ko
>>
>
> If there are multiple sets of modules underneath a path, you have to be
> more precise, /opt/root/ubuntu-vivid.x86_64/lib/modules/4.5.0+ in this case.
>
>>
>> Unfortunately I can't see any reference to a vfs path in:
>> print $lx_module("helloworld")
>>
>> So we can't retrieve the exact path location from the kernel information
>> Have you experienced this issue?
>
> No, because I'm always using lx-symbols against the build output, not
> against installed modules. But even then, see above, I don't see a
> problem is the path is properly specified.
>
Ok, I see. I guess it's just a different use-case. ST had this factored
out so that the user did not have to do much other than specify the root
path. And in fact, the 'user' didn't do this as it was pre-set.
I had even toyed with the idea that we could parse the commandline - and
if we detect an nfsroot, automatically provide that on the search path.
Perhaps we'll put this on the to-think-about stack for now then on this
side :)
Specifying the full path to modules isn't an unreasonable solution IMO,
so it will just come down to a user-experience thing. The automatic
detection could just be classed as a nice feature for the future perhaps.
Peter et al, do you have any opinion on this?
--
Kieran
> Jan
>
>>
>> Perhaps we ought to prefix our search path with
>> $(path_item)/lib/modules/`uname -r`
>>
>>
>> ST's C implementation of module support can be seen at:
>>
>> https://git.linaro.org/people/kieran.bingham/binutils-gdb.git/blob/e30a18cf086bd02c4ebb57f6f783fe2ad4af9c84:/gdb/stlinux/lkd-modules.c
>>
>> They restrict the search paths, and parse expected
>> lib/modules/{version}/ paths to ensure the correct modules are discovered.
>>
>> --
>> Regards
>>
>> Kieran
>>
>
>
Re: gdb/scripts: Module symbol search paths
On 14/03/16 10:36, Jan Kiszka wrote:
> Hi Kieran,
>
> On 2016-03-14 11:20, Kieran Bingham wrote:
>> Hi Jan,
>>
>> Whilst testing the modules update patch you sent, I discovered (due to
>> having rebased to v4.5) that the module search path will end up picking
>> an incorrect version of the .ko file if an earlier version exists.:
>>
>>
>> (gdb) lx-symbols /opt/root/ubuntu-vivid.x86_64
>> loading vmlinux
>> (gdb) c
>> Continuing.
>> < load module helloworld.ko on target >
>> scanning for modules in /opt/root/ubuntu-vivid.x86_64
>> loading @0xa000:
>> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.4.0+/extra/helloworld.ko
>>
>> Looking at the filesystem layout:
>>
>> kbingham@CookieMonster:~$ sudo find /opt/root/ubuntu-vivid.x86_64/ -name
>> helloworld.ko
>> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.4.0+/extra/helloworld.ko
>> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.5.0+/extra/helloworld.ko
>>
>
> If there are multiple sets of modules underneath a path, you have to be
> more precise, /opt/root/ubuntu-vivid.x86_64/lib/modules/4.5.0+ in this case.
>
>>
>> Unfortunately I can't see any reference to a vfs path in:
>> print $lx_module("helloworld")
>>
>> So we can't retrieve the exact path location from the kernel information
>> Have you experienced this issue?
>
> No, because I'm always using lx-symbols against the build output, not
> against installed modules. But even then, see above, I don't see a
> problem is the path is properly specified.
>
Ok, I see. I guess it's just a different use-case. ST had this factored
out so that the user did not have to do much other than specify the root
path. And in fact, the 'user' didn't do this as it was pre-set.
I had even toyed with the idea that we could parse the commandline - and
if we detect an nfsroot, automatically provide that on the search path.
Perhaps we'll put this on the to-think-about stack for now then on this
side :)
Specifying the full path to modules isn't an unreasonable solution IMO,
so it will just come down to a user-experience thing. The automatic
detection could just be classed as a nice feature for the future perhaps.
Peter et al, do you have any opinion on this?
--
Kieran
> Jan
>
>>
>> Perhaps we ought to prefix our search path with
>> $(path_item)/lib/modules/`uname -r`
>>
>>
>> ST's C implementation of module support can be seen at:
>>
>> https://git.linaro.org/people/kieran.bingham/binutils-gdb.git/blob/e30a18cf086bd02c4ebb57f6f783fe2ad4af9c84:/gdb/stlinux/lkd-modules.c
>>
>> They restrict the search paths, and parse expected
>> lib/modules/{version}/ paths to ensure the correct modules are discovered.
>>
>> --
>> Regards
>>
>> Kieran
>>
>
>
Re: gdb/scripts: Module symbol search paths
Hi Kieran,
On 2016-03-14 11:20, Kieran Bingham wrote:
> Hi Jan,
>
> Whilst testing the modules update patch you sent, I discovered (due to
> having rebased to v4.5) that the module search path will end up picking
> an incorrect version of the .ko file if an earlier version exists.:
>
>
> (gdb) lx-symbols /opt/root/ubuntu-vivid.x86_64
> loading vmlinux
> (gdb) c
> Continuing.
> < load module helloworld.ko on target >
> scanning for modules in /opt/root/ubuntu-vivid.x86_64
> loading @0xa000:
> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.4.0+/extra/helloworld.ko
>
> Looking at the filesystem layout:
>
> kbingham@CookieMonster:~$ sudo find /opt/root/ubuntu-vivid.x86_64/ -name
> helloworld.ko
> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.4.0+/extra/helloworld.ko
> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.5.0+/extra/helloworld.ko
>
If there are multiple sets of modules underneath a path, you have to be
more precise, /opt/root/ubuntu-vivid.x86_64/lib/modules/4.5.0+ in this case.
>
> Unfortunately I can't see any reference to a vfs path in:
> print $lx_module("helloworld")
>
> So we can't retrieve the exact path location from the kernel information
> Have you experienced this issue?
No, because I'm always using lx-symbols against the build output, not
against installed modules. But even then, see above, I don't see a
problem is the path is properly specified.
Jan
>
> Perhaps we ought to prefix our search path with
> $(path_item)/lib/modules/`uname -r`
>
>
> ST's C implementation of module support can be seen at:
>
> https://git.linaro.org/people/kieran.bingham/binutils-gdb.git/blob/e30a18cf086bd02c4ebb57f6f783fe2ad4af9c84:/gdb/stlinux/lkd-modules.c
>
> They restrict the search paths, and parse expected
> lib/modules/{version}/ paths to ensure the correct modules are discovered.
>
> --
> Regards
>
> Kieran
>
--
Siemens AG, Corporate Technology, CT RDA ITP SES-DE
Corporate Competence Center Embedded Linux
Re: gdb/scripts: Module symbol search paths
Hi Kieran,
On 2016-03-14 11:20, Kieran Bingham wrote:
> Hi Jan,
>
> Whilst testing the modules update patch you sent, I discovered (due to
> having rebased to v4.5) that the module search path will end up picking
> an incorrect version of the .ko file if an earlier version exists.:
>
>
> (gdb) lx-symbols /opt/root/ubuntu-vivid.x86_64
> loading vmlinux
> (gdb) c
> Continuing.
> < load module helloworld.ko on target >
> scanning for modules in /opt/root/ubuntu-vivid.x86_64
> loading @0xa000:
> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.4.0+/extra/helloworld.ko
>
> Looking at the filesystem layout:
>
> kbingham@CookieMonster:~$ sudo find /opt/root/ubuntu-vivid.x86_64/ -name
> helloworld.ko
> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.4.0+/extra/helloworld.ko
> /opt/root/ubuntu-vivid.x86_64/lib/modules/4.5.0+/extra/helloworld.ko
>
If there are multiple sets of modules underneath a path, you have to be
more precise, /opt/root/ubuntu-vivid.x86_64/lib/modules/4.5.0+ in this case.
>
> Unfortunately I can't see any reference to a vfs path in:
> print $lx_module("helloworld")
>
> So we can't retrieve the exact path location from the kernel information
> Have you experienced this issue?
No, because I'm always using lx-symbols against the build output, not
against installed modules. But even then, see above, I don't see a
problem is the path is properly specified.
Jan
>
> Perhaps we ought to prefix our search path with
> $(path_item)/lib/modules/`uname -r`
>
>
> ST's C implementation of module support can be seen at:
>
> https://git.linaro.org/people/kieran.bingham/binutils-gdb.git/blob/e30a18cf086bd02c4ebb57f6f783fe2ad4af9c84:/gdb/stlinux/lkd-modules.c
>
> They restrict the search paths, and parse expected
> lib/modules/{version}/ paths to ensure the correct modules are discovered.
>
> --
> Regards
>
> Kieran
>
--
Siemens AG, Corporate Technology, CT RDA ITP SES-DE
Corporate Competence Center Embedded Linux
