docs: netdev: additional info requirements for bug fixes

Knowing how AI-generated patches were tested would be a great help
when reviewing them. Explicitly ask people to describe the discovery
and validation process they followed.

I posted this as an RFC a while back and there were some concerns
from developers that it would gum up the process. With Linus's
recent complaints about the size of our PRs, we really need
this information. I launched an AI bot which complains if
people don't explain how bugs were discovered and tested
(look for netdev-bot+sinfo@kernel.org, s=series info).
We need to document this requirement.

Reviewed-by: Nicolai Buchwitz <nb@tipi-net.de>
Acked-by: Daniel Machon <daniel.machon@microchip.com>
Link: https://patch.msgid.link/20260930163109.3910509-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/process/maintainer-netdev.rst

@@ -283,6 +283,38 @@ as a patch to the list with a commit message explaining the technical
 problems with the reverted commit. Reverts should be used as a last resort,
 when original change is completely wrong; incremental fixes are preferred.
 
+Bug fixes
+~~~~~~~~~
+
+All bug fixes must state how the issue was discovered and validated,
+and how the fix was tested. This should be done in plain English, not with
+special tags or annotations. That said, the information does not have to be
+provided if the existing trailers imply it (e.g. ``Reported-by: syzbot...``
+implies the discovery method and validation).
+
+Example statements describing discovery:
+
+ - discovered by a non-AI static analysis tool
+ - discovered by an AI code review agent
+ - discovered by manual code inspection
+ - triggered during code development
+ - triggered in CI testing
+ - observed on a machine in real use
+
+If the discovery method does not imply the issue was triggered, the commit
+message should describe the validation, i.e. how the bug was confirmed
+to be real. The commit message must disclose whether reproducing the issue
+required modifying the kernel (e.g. inserting a delay to widen a race, or
+writing a loadable module to issue the right sequence of calls) or using error
+injection. The reproduction steps should be included in the commit message
+if they are short (roughly 10 lines or fewer); longer reproducers can be posted
+online with a link included.
+
+The testing statement should explain whether the fix was tested against the
+reproducer and against kernel selftests. If the bug is in a hardware driver,
+the testing statement must include information about the HW on which the
+fix was tested.
+
 Stable tree
 ~~~~~~~~~~~