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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH] mm: kmemleak: add CONFIG_DEBUG_KMEMLEAK_VERBOSE build option Message-ID: <0dfd659a-f4c8-4356-9b14-960ca70c0d68@lucifer.local> References: <20260323-kmemleak_report-v1-1-ba2cdd9c11b9@debian.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260323-kmemleak_report-v1-1-ba2cdd9c11b9@debian.org> X-Rspamd-Queue-Id: DD71E20008 X-Stat-Signature: 96gc4qsuf1d9ed5gakcrnw4rqo4koxcs X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1774357668-112210 X-HE-Meta: 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 AI14G+Xp 5f4tHSSGuJNcvufs8FfnWo+KNMXTJeV7zJ/BzCXgkqqiGszLc0bvaTGkcVxadDs59WMmz3XHcq1O/oP81y/jfCkzB52LYDR/QGhGha0pMiDPeGZaYFBv3oNj4wQEZylcn3sR4aRrFNTDCPjL6+OuO4UE7S0xRZuYoq/U2wKIUVSkElWG01BPhcGvBKs471g97NAoW0S54Uale4+7bvYRv4oLeqcQtOCb2zVlDS2Wj6X/VTj52WmVWh1LweZxQxiDTMUVUlIOhNcy3Y3PANw5sU5hTxrhNtpeG8j3n4aUVXzTWtSA12Ub9A7zuPQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Mar 23, 2026 at 04:12:13AM -0700, Breno Leitao wrote: > Add a Kconfig option to default kmemleak verbose mode on at build time. > This option depends on DEBUG_KMEMLEAK_AUTO_SCAN since verbose reporting > is only meaningful when the automatic scanning thread is running. > > When enabled, kmemleak prints full details (backtrace, hex dump, address) > of unreferenced objects to dmesg as they are detected during scanning, > removing the need to manually read /sys/kernel/debug/kmemleak. > > Making this a compile-time option rather than a boot parameter allows > debug kernel flavors to enable verbose kmemleak reporting by default > without requiring changes to boot arguments. A machine can simply swap > to a debug kernel and benefit from kmemleak reporting automatically. > > By surfacing leak reports directly in dmesg, they are automatically > forwarded through any kernel logging infrastructure and can be easily > captured by log aggregation tooling, making it practical to monitor > memory leaks across large fleets. > > The verbose setting can still be toggled at runtime via > /sys/module/kmemleak/parameters/verbose. > > Signed-off-by: Breno Leitao This seems reasonable, so: Reviewed-by: Lorenzo Stoakes (Oracle) Cheers, Lorenzo > --- > mm/Kconfig.debug | 11 +++++++++++ > mm/kmemleak.c | 2 +- > 2 files changed, 12 insertions(+), 1 deletion(-) > > diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug > index 7638d75b27db8..91b3e027b7535 100644 > --- a/mm/Kconfig.debug > +++ b/mm/Kconfig.debug > @@ -297,6 +297,17 @@ config DEBUG_KMEMLEAK_AUTO_SCAN > > If unsure, say Y. > > +config DEBUG_KMEMLEAK_VERBOSE > + bool "Default kmemleak to verbose mode" > + depends on DEBUG_KMEMLEAK_AUTO_SCAN > + help > + Say Y here to have kmemleak print unreferenced object details > + (backtrace, hex dump, address) to dmesg when new memory leaks are > + detected during automatic scanning. This can also be toggled at > + runtime via /sys/module/kmemleak/parameters/verbose. > + > + If unsure, say N. > + > config PER_VMA_LOCK_STATS > bool "Statistics for per-vma locks" > depends on PER_VMA_LOCK > diff --git a/mm/kmemleak.c b/mm/kmemleak.c > index fa8201e232221..2eff0d6b622b6 100644 > --- a/mm/kmemleak.c > +++ b/mm/kmemleak.c > @@ -241,7 +241,7 @@ static int kmemleak_skip_disable; > /* If there are leaks that can be reported */ > static bool kmemleak_found_leaks; > > -static bool kmemleak_verbose; > +static bool kmemleak_verbose = IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_VERBOSE); > module_param_named(verbose, kmemleak_verbose, bool, 0600); > > static void kmemleak_disable(void); > > --- > base-commit: 785f0eb2f85decbe7c1ef9ae922931f0194ffc2e > change-id: 20260323-kmemleak_report-a9a103ee0c8c > > Best regards, > -- > Breno Leitao >