From: Andrew Morton <akpm@linux-foundation.org>
To: mm-commits@vger.kernel.org,tglx@linutronix.de,glider@google.com,elver@google.com,dvyukov@google.com,corbet@lwn.net,arnd@arndb.de,andreyknvl@gmail.com,soham.bagchi@utah.edu,akpm@linux-foundation.org
Subject: [folded-merged] kcov-load-acquire-coverage-count-in-user-space-code-v2.patch removed from -mm tree
Date: Sat, 13 Sep 2025 17:14:48 -0700 [thread overview]
Message-ID: <20250914001448.DA005C4CEEB@smtp.kernel.org> (raw)
The quilt patch titled
Subject: kcov-load-acquire-coverage-count-in-user-space-code-v2
has been removed from the -mm tree. Its filename was
kcov-load-acquire-coverage-count-in-user-space-code-v2.patch
This patch was dropped because it was folded into kcov-load-acquire-coverage-count-in-user-space-code.patch
------------------------------------------------------
From: Soham Bagchi <soham.bagchi@utah.edu>
Subject: kcov-load-acquire-coverage-count-in-user-space-code-v2
Date: Sun, 3 Aug 2025 12:05:58 -0600
note for load-acquire shifted to block comment in code rather than in the
preceding paragraphs, per Marco
Link: https://lkml.kernel.org/r/20250803180558.2967962-1-soham.bagchi@utah.edu
Signed-off-by: Soham Bagchi <soham.bagchi@utah.edu>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marco Elver <elver@google.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
Documentation/dev-tools/kcov.rst | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
--- a/Documentation/dev-tools/kcov.rst~kcov-load-acquire-coverage-count-in-user-space-code-v2
+++ a/Documentation/dev-tools/kcov.rst
@@ -287,11 +287,6 @@ handle instance id.
The following program demonstrates using KCOV to collect coverage from both
local tasks spawned by the process and the global task that handles USB bus #1:
-The user-space code for KCOV should also use an acquire to fetch the count
-of coverage entries in the shared buffer. This acquire pairs with the
-corresponding write memory barrier (smp_wmb()) on the kernel-side in
-kcov_move_area().
-
.. code-block:: c
/* Same includes and defines as above. */
@@ -366,6 +361,11 @@ kcov_move_area().
*/
sleep(2);
+ /*
+ * The load to the coverage count should be an acquire to pair with
+ * pair with the corresponding write memory barrier (smp_wmb()) on
+ * the kernel-side in kcov_move_area().
+ */
n = __atomic_load_n(&cover[0], __ATOMIC_ACQUIRE);
for (i = 0; i < n; i++)
printf("0x%lx\n", cover[i + 1]);
_
Patches currently in -mm which might be from soham.bagchi@utah.edu are
kcov-use-write-memory-barrier-after-memcpy-in-kcov_move_area.patch
kcov-load-acquire-coverage-count-in-user-space-code.patch
reply other threads:[~2025-09-14 0:14 UTC|newest]
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