[PATCH v2] kcov: update documentation on remote coverage collection

[Jann Horn]

Adjust the docs on remote coverage collection to reflect the changes made
in "kcov: refactor common handle ID into kcov_common_handle_id" and
"kcov: allow simultaneous KCOV_ENABLE/KCOV_REMOTE_ENABLE".

Suggested-by: Alexander Potapenko <glider@xxxxxxxxxx>
Signed-off-by: Jann Horn <jannh@xxxxxxxxxx>
---
Changes in v2:
- move and reword sentence on simultaneous normal/remote collection (andreyknvl)
- Link to v1: https://lore.kernel.org/r/20260519-kcov-docs-v1-1-5bb22f4cb20c@xxxxxxxxxx
---
 Documentation/dev-tools/kcov.rst | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/dev-tools/kcov.rst b/Documentation/dev-tools/kcov.rst
index 8127849d40f5..1a739290c8ec 100644
--- a/Documentation/dev-tools/kcov.rst
+++ b/Documentation/dev-tools/kcov.rst
@@ -237,6 +237,9 @@ Both ``kcov_remote_start`` and ``kcov_remote_stop`` annotations and the
 collection sections. The way a handle is used depends on the context where the
 matching code section executes.
 
+A thread can use two separate KCOV instances to collect remote coverage and
+normal coverage at the same time.
+
 KCOV supports collecting remote coverage from the following contexts:
 
 1. Global kernel background tasks. These are the tasks that are spawned during
@@ -262,6 +265,9 @@ gets saved to the ``kcov_handle`` field in the current ``task_struct`` and
 needs to be passed to the newly spawned local tasks via custom kernel code
 modifications. Those tasks should in turn use the passed handle in their
 ``kcov_remote_start`` and ``kcov_remote_stop`` annotations.
+In the kernel, common handles are wrapped in a ``kcov_common_handle_id``, which
+consumes no space in builds without ``CONFIG_KCOV``; subsystems that integrate
+with this mechanism should not need to use any ``#ifdef CONFIG_KCOV`` or such.
 
 KCOV follows a predefined format for both global and common handles. Each
 handle is a ``u64`` integer. Currently, only the one top and the lower 4 bytes

---
base-commit: ab5fce87a778cb780a05984a2ca448f2b41aafbf
change-id: 20260519-kcov-docs-15feabfb10aa

--  
Jann Horn <jannh@xxxxxxxxxx>