Re: [PATCH] docs: kdoc: fix duplicate section warning message

Hi Jacob,

On 10/29/25 11:30 AM, Jacob Keller wrote:

The python version of the kernel-doc parser emits some strange warnings
with just a line number in certain cases:

$ ./scripts/kernel-doc -Wall -none 'include/linux/virtio_config.h'
Warning: 174
Warning: 184
Warning: 190
Warning: include/linux/virtio_config.h:226 No description found for return value of '__virtio_test_bit'
Warning: include/linux/virtio_config.h:259 No description found for return value of 'virtio_has_feature'
Warning: include/linux/virtio_config.h:283 No description found for return value of 'virtio_has_dma_quirk'
Warning: include/linux/virtio_config.h:392 No description found for return value of 'virtqueue_set_affinity'

I eventually tracked this down to the lone call of emit_msg() in the
KernelEntry class, which looks like:

  self.emit_msg(self.new_start_line, f"duplicate section name '{name}'\n")

This looks like all the other emit_msg calls. Unfortunately, the definition
within the KernelEntry class takes only a message parameter and not a line
number. The intended message is passed as the warning!

Pass the filename to the KernelEntry class, and use this to build the log
message in the same way as the KernelDoc class does.

To avoid future errors, mark the warning parameter for both emit_msg
definitions as a keyword-only argument. This will prevent accidentally
passing a string as the warning parameter in the future.

Also fix the call in dump_section to avoid an unnecessary additional
newline.

Fixes: e3b42e94cf10 ("scripts/lib/kdoc/kdoc_parser.py: move kernel entry to a class")
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
---
We recently discovered this while working on some netdev text
infrastructure. All of the duplicate section warnings are not being logged
properly, which was confusing the warning comparison logic we have for
testing patches in NIPA.

This appears to have been caused by the optimizations in:
https://lore.kernel.org/all/cover.1745564565.git.mchehab+huawei@kernel.org/ (local)

Before this fix:
$ ./scripts/kernel-doc -Wall -none 'include/linux/virtio_config.h'
Warning: 174
Warning: 184
Warning: 190
Warning: include/linux/virtio_config.h:226 No description found for return value of '__virtio_test_bit'
Warning: include/linux/virtio_config.h:259 No description found for return value of 'virtio_has_feature'
Warning: include/linux/virtio_config.h:283 No description found for return value of 'virtio_has_dma_quirk'
Warning: include/linux/virtio_config.h:392 No description found for return value of 'virtqueue_set_affinity'

After this fix:
$ ./scripts/kernel-doc -Wall -none 'include/linux/virtio_config.h'
Warning: include/linux/virtio_config.h:174 duplicate section name 'Return'
Warning: include/linux/virtio_config.h:184 duplicate section name 'Return'
Warning: include/linux/virtio_config.h:190 duplicate section name 'Return'
Warning: include/linux/virtio_config.h:226 No description found for return value of '__virtio_test_bit'
Warning: include/linux/virtio_config.h:259 No description found for return value of 'virtio_has_feature'
Warning: include/linux/virtio_config.h:283 No description found for return value of 'virtio_has_dma_quirk'
Warning: include/linux/virtio_config.h:392 No description found for return value of 'virtqueue_set_affinity'
---
 scripts/lib/kdoc/kdoc_parser.py | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

---
base-commit: e53642b87a4f4b03a8d7e5f8507fc3cd0c595ea6
change-id: 20251029-jk-fix-kernel-doc-duplicate-return-warning-bd57ea39c628

What is that base-commit? I don't have it.
It doesn't apply to linux-next (I didn't check docs-next).
It does apply cleanly to kernel v6.18-rc3.

and it does fix the Warning messages to be something useful. Thanks.

We'll have to see if Mauro already has a fix for this. (I reported
it a couple of weeks ago.)
If not, then this will need to apply to docs-next AFAIK.

And not a problem with this patch, but those Returns: lines for
each callback function shouldn't be there as Returns:. This is a
struct declaration, not a function (or macro) declaration/definition.

Thanks.
-- 
~Randy