+ documentation-kmemleak-describe-the-metadata-pool-not-the-early-log.patch added to mm-new branch

+ documentation-kmemleak-describe-the-metadata-pool-not-the-early-log.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: Documentation: kmemleak: describe the metadata pool, not the early log
has been added to the -mm mm-new branch.  Its filename is
     documentation-kmemleak-describe-the-metadata-pool-not-the-early-log.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/documentation-kmemleak-describe-the-metadata-pool-not-the-early-log.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: Breno Leitao <leitao@debian.org>
Subject: Documentation: kmemleak: describe the metadata pool, not the early log
Date: Thu, 17 Sep 2026 06:47:35 -0700

Patch series "kmemleak: fix stale documentation and raise the verbose
default".

The first two patches fix statements in
Documentation/dev-tools/kmemleak.rst that do not match mm/kmemleak.c.

The third requires one more consecutive unreferenced scan before a
CONFIG_DEBUG_KMEMLEAK_VERBOSE kernel reports a leak on the console, to
avoid the last false positives I am seeing when running
CONFIG_DEBUG_KMEMLEAK_VERBOSE on a daily basis.


This patch (of 3):

commit c5665868183f ("mm: kmemleak: use the memory pool for early
allocations") removed the early log buffer in favour of a static pool of
kmemleak_object structures, but the documentation still describes the old
mechanism.

Fix the documentation by describing what the pool actually is, matching
the Kconfig help text.

Link: https://lore.kernel.org/20260917142210.90829-1-sj@kernel.org
Link: https://lore.kernel.org/20260917-b4-kmemleak-doc-v1-1-84fde6d1f749@debian.org
Fixes: c5665868183f ("mm: kmemleak: use the memory pool for early allocations")
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Randy Dunlap <rdunlap@infradead.org>
---

 Documentation/dev-tools/kmemleak.rst |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

--- a/Documentation/dev-tools/kmemleak.rst~documentation-kmemleak-describe-the-metadata-pool-not-the-early-log
+++ a/Documentation/dev-tools/kmemleak.rst
@@ -66,9 +66,14 @@ Memory scanning parameters can be modifi
 Kmemleak can also be disabled at boot-time by passing ``kmemleak=off`` on
 the kernel command line.
 
-Memory may be allocated or freed before kmemleak is initialised and
-these actions are stored in an early log buffer. The size of this buffer
-is configured via the CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE option.
+Memory may be allocated or freed before kmemleak is initialised, so a
+static pool of metadata objects is used to track those allocations. Once
+kmemleak is fully initialised the pool becomes an emergency reserve, used
+whenever a metadata object cannot be allocated from the slab. The number
+of objects in the pool is configured via the
+CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE option. Exhausting it at run time
+prints "Cannot allocate a kmemleak_object structure" and disables
+kmemleak.
 
 If CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF are enabled, the kmemleak is
 disabled by default. Passing ``kmemleak=on`` on the kernel command
_

Patches currently in -mm which might be from leitao@debian.org are

mm-swap-distinguish-a-malformed-swap-entry-from-a-dying-device.patch
mm-fail-the-fault-on-a-malformed-swap-entry-instead-of-retrying-it.patch
documentation-kmemleak-describe-the-metadata-pool-not-the-early-log.patch
documentation-kmemleak-fix-stale-statements-about-scanning.patch
mm-kmemleak-raise-min_unref_scans-to-3-for-verbose-auto-scan.patch