scripts/gdb: fix parsing of MNT_* constants

[PATCH v1] scripts/gdb: fix parsing of MNT_* constants

Posted by Tony Ambardar 8 months, 1 week ago

Recently, constants in linux/mount.h were changed from integer macros
parsable by LX_VALUE() to enums which are not, thus breaking gdb python
scripts:

  Reading symbols from vmlinux...
  Traceback (most recent call last):
    File ".../linux/vmlinux-gdb.py", line 25, in <module>
      import linux.constants
    File ".../linux/scripts/gdb/linux/constants.py", line 19, in <module>
      LX_MNT_NOSUID = MNT_NOSUID
  NameError: name 'MNT_NOSUID' is not defined

Update to parse with LX_GDBPARSED(), which correctly handles enums.

Fixes: 101f2bbab541 ("fs: convert mount flags to enum")
Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
---
 scripts/gdb/linux/constants.py.in | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/scripts/gdb/linux/constants.py.in b/scripts/gdb/linux/constants.py.in
index fd6bd69c5096..d5e3069f42a7 100644
--- a/scripts/gdb/linux/constants.py.in
+++ b/scripts/gdb/linux/constants.py.in
@@ -73,12 +73,12 @@ if IS_BUILTIN(CONFIG_MODULES):
     LX_GDBPARSED(MOD_RO_AFTER_INIT)
 
 /* linux/mount.h */
-LX_VALUE(MNT_NOSUID)
-LX_VALUE(MNT_NODEV)
-LX_VALUE(MNT_NOEXEC)
-LX_VALUE(MNT_NOATIME)
-LX_VALUE(MNT_NODIRATIME)
-LX_VALUE(MNT_RELATIME)
+LX_GDBPARSED(MNT_NOSUID)
+LX_GDBPARSED(MNT_NODEV)
+LX_GDBPARSED(MNT_NOEXEC)
+LX_GDBPARSED(MNT_NOATIME)
+LX_GDBPARSED(MNT_NODIRATIME)
+LX_GDBPARSED(MNT_RELATIME)
 
 /* linux/threads.h */
 LX_VALUE(NR_CPUS)
-- 
2.34.1

Re: [PATCH v1] scripts/gdb: fix parsing of MNT_* constants

Posted by Stephen Brennan 8 months, 1 week ago

On 5/31/25 22:50, Tony Ambardar wrote:
> Recently, constants in linux/mount.h were changed from integer macros
> parsable by LX_VALUE() to enums which are not, thus breaking gdb python
> scripts:
> 
>   Reading symbols from vmlinux...
>   Traceback (most recent call last):
>     File ".../linux/vmlinux-gdb.py", line 25, in <module>
>       import linux.constants
>     File ".../linux/scripts/gdb/linux/constants.py", line 19, in <module>
>       LX_MNT_NOSUID = MNT_NOSUID
>   NameError: name 'MNT_NOSUID' is not defined
> 
> Update to parse with LX_GDBPARSED(), which correctly handles enums.
> 
> Fixes: 101f2bbab541 ("fs: convert mount flags to enum")
> Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>

Hi Tony,

I was totally unaware that these constants were being consumed by
another debugger, and having fixed them for one, I broke them for another!

Thanks for the fix. Having read through the preprocessor magic and this
change, they make sense to me. In the future, I'll be sure to make an
extra check for GDB users when updating enums.

Reviewed-by: Stephen Brennan <stephen.s.brennan@oracle.com>

> ---
>  scripts/gdb/linux/constants.py.in | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/scripts/gdb/linux/constants.py.in b/scripts/gdb/linux/constants.py.in
> index fd6bd69c5096..d5e3069f42a7 100644
> --- a/scripts/gdb/linux/constants.py.in
> +++ b/scripts/gdb/linux/constants.py.in
> @@ -73,12 +73,12 @@ if IS_BUILTIN(CONFIG_MODULES):
>      LX_GDBPARSED(MOD_RO_AFTER_INIT)
>  
>  /* linux/mount.h */
> -LX_VALUE(MNT_NOSUID)
> -LX_VALUE(MNT_NODEV)
> -LX_VALUE(MNT_NOEXEC)
> -LX_VALUE(MNT_NOATIME)
> -LX_VALUE(MNT_NODIRATIME)
> -LX_VALUE(MNT_RELATIME)
> +LX_GDBPARSED(MNT_NOSUID)
> +LX_GDBPARSED(MNT_NODEV)
> +LX_GDBPARSED(MNT_NOEXEC)
> +LX_GDBPARSED(MNT_NOATIME)
> +LX_GDBPARSED(MNT_NODIRATIME)
> +LX_GDBPARSED(MNT_RELATIME)
>  
>  /* linux/threads.h */
>  LX_VALUE(NR_CPUS)

Re: [PATCH v1] scripts/gdb: fix parsing of MNT_* constants

Posted by Florian Fainelli 8 months, 1 week ago

On 6/2/25 21:42, Stephen Brennan wrote:
> On 5/31/25 22:50, Tony Ambardar wrote:
>> Recently, constants in linux/mount.h were changed from integer macros
>> parsable by LX_VALUE() to enums which are not, thus breaking gdb python
>> scripts:
>>
>>    Reading symbols from vmlinux...
>>    Traceback (most recent call last):
>>      File ".../linux/vmlinux-gdb.py", line 25, in <module>
>>        import linux.constants
>>      File ".../linux/scripts/gdb/linux/constants.py", line 19, in <module>
>>        LX_MNT_NOSUID = MNT_NOSUID
>>    NameError: name 'MNT_NOSUID' is not defined
>>
>> Update to parse with LX_GDBPARSED(), which correctly handles enums.
>>
>> Fixes: 101f2bbab541 ("fs: convert mount flags to enum")
>> Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
> 
> Hi Tony,
> 
> I was totally unaware that these constants were being consumed by
> another debugger, and having fixed them for one, I broke them for another!
> 
> Thanks for the fix. Having read through the preprocessor magic and this
> change, they make sense to me. In the future, I'll be sure to make an
> extra check for GDB users when updating enums.
> 
> Reviewed-by: Stephen Brennan <stephen.s.brennan@oracle.com>

Not targeted to anyone in particular but this is a recurring problem, 
the GDB scripts are typically not part of any CI and it is not natural 
to grep for constant names outside of the C/Rust code where they are 
being used...

I suppose that QEMU it should be much easier to ensure that GDB scripts 
are being exercised than with my current set-up using OpenOCD + real 
hardware...

Thanks
-- 
Florian

Re: [PATCH v1] scripts/gdb: fix parsing of MNT_* constants

Posted by Florian Fainelli 7 months, 3 weeks ago

On 6/3/25 09:17, Florian Fainelli wrote:
> On 6/2/25 21:42, Stephen Brennan wrote:
>> On 5/31/25 22:50, Tony Ambardar wrote:
>>> Recently, constants in linux/mount.h were changed from integer macros
>>> parsable by LX_VALUE() to enums which are not, thus breaking gdb python
>>> scripts:
>>>
>>>    Reading symbols from vmlinux...
>>>    Traceback (most recent call last):
>>>      File ".../linux/vmlinux-gdb.py", line 25, in <module>
>>>        import linux.constants
>>>      File ".../linux/scripts/gdb/linux/constants.py", line 19, in 
>>> <module>
>>>        LX_MNT_NOSUID = MNT_NOSUID
>>>    NameError: name 'MNT_NOSUID' is not defined
>>>
>>> Update to parse with LX_GDBPARSED(), which correctly handles enums.
>>>
>>> Fixes: 101f2bbab541 ("fs: convert mount flags to enum")
>>> Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
>>
>> Hi Tony,
>>
>> I was totally unaware that these constants were being consumed by
>> another debugger, and having fixed them for one, I broke them for 
>> another!
>>
>> Thanks for the fix. Having read through the preprocessor magic and this
>> change, they make sense to me. In the future, I'll be sure to make an
>> extra check for GDB users when updating enums.
>>
>> Reviewed-by: Stephen Brennan <stephen.s.brennan@oracle.com>
> 
> Not targeted to anyone in particular but this is a recurring problem, 
> the GDB scripts are typically not part of any CI and it is not natural 
> to grep for constant names outside of the C/Rust code where they are 
> being used...
> 
> I suppose that QEMU it should be much easier to ensure that GDB scripts 
> are being exercised than with my current set-up using OpenOCD + real 
> hardware...

And also:

Tested-by: Florian Fainelli <florian.fainelli@broadcom.com>

Jan, Kieran, can you please pick this up? Thanks!
-- 
Florian

Re: [PATCH v1] scripts/gdb: fix parsing of MNT_* constants

Posted by Jan Kiszka 7 months, 3 weeks ago

On 19.06.25 23:51, Florian Fainelli wrote:
> On 6/3/25 09:17, Florian Fainelli wrote:
>> On 6/2/25 21:42, Stephen Brennan wrote:
>>> On 5/31/25 22:50, Tony Ambardar wrote:
>>>> Recently, constants in linux/mount.h were changed from integer macros
>>>> parsable by LX_VALUE() to enums which are not, thus breaking gdb python
>>>> scripts:
>>>>
>>>>    Reading symbols from vmlinux...
>>>>    Traceback (most recent call last):
>>>>      File ".../linux/vmlinux-gdb.py", line 25, in <module>
>>>>        import linux.constants
>>>>      File ".../linux/scripts/gdb/linux/constants.py", line 19, in
>>>> <module>
>>>>        LX_MNT_NOSUID = MNT_NOSUID
>>>>    NameError: name 'MNT_NOSUID' is not defined
>>>>
>>>> Update to parse with LX_GDBPARSED(), which correctly handles enums.
>>>>
>>>> Fixes: 101f2bbab541 ("fs: convert mount flags to enum")
>>>> Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
>>>
>>> Hi Tony,
>>>
>>> I was totally unaware that these constants were being consumed by
>>> another debugger, and having fixed them for one, I broke them for
>>> another!
>>>
>>> Thanks for the fix. Having read through the preprocessor magic and this
>>> change, they make sense to me. In the future, I'll be sure to make an
>>> extra check for GDB users when updating enums.
>>>
>>> Reviewed-by: Stephen Brennan <stephen.s.brennan@oracle.com>
>>
>> Not targeted to anyone in particular but this is a recurring problem,
>> the GDB scripts are typically not part of any CI and it is not natural
>> to grep for constant names outside of the C/Rust code where they are
>> being used...
>>
>> I suppose that QEMU it should be much easier to ensure that GDB
>> scripts are being exercised than with my current set-up using OpenOCD
>> + real hardware...
> 
> And also:
> 
> Tested-by: Florian Fainelli <florian.fainelli@broadcom.com>
> 
> Jan, Kieran, can you please pick this up? Thanks!

Thanks for all the fixes. The version of Johannes has already been 
queued up by Andrew:

https://lore.kernel.org/mm-commits/20250618223437.C3BB2C4CEE7@smtp.kernel.org/T/#u

Regarding automated testing: This would indeed be a valuable addition. 
Some QEMU-based tests should suffice, but I do not know where those 
could be best hooked into for broad visibility. To my understanding, 
KernelCI is right now focusing on single device boot tests, and we would 
rather need some backend/frontend test setup here even when only using a 
virtual device. Some self-built pipeline could provide that as well - 
but where/how to report findings then? Ideas welcome.

And then it would obviously also need some folks willing to contribute 
the actual test cases.

Jan

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