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Mon, 6 Feb 2023 15:36:36 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id Rz5MMIQe4WP+bwAAMHmgww (envelope-from ); Mon, 06 Feb 2023 15:36:36 +0000 Message-ID: <74aa9287-51c5-7179-839a-66a17ea85617@suse.cz> Date: Mon, 6 Feb 2023 16:36:36 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH] mm/slub: fix memory leak with using debugfs_lookup() Content-Language: en-US To: Greg Kroah-Hartman , linux-mm@kvack.org Cc: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, linux-kernel@vger.kernel.org References: <20230202142022.2300096-1-gregkh@linuxfoundation.org> From: Vlastimil Babka In-Reply-To: <20230202142022.2300096-1-gregkh@linuxfoundation.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: w7abm4f61qzf1e49wegrgyophtpxdrnx X-Rspam-User: X-Rspamd-Queue-Id: 9542A4000A X-Rspamd-Server: rspam06 X-HE-Tag: 1675697798-730381 X-HE-Meta: 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 8O7lCPiJ 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2/2/23 15:20, Greg Kroah-Hartman wrote: > When calling debugfs_lookup() the result must have dput() called on it, > otherwise the memory will leak over time. To make things simpler, just > call debugfs_lookup_and_remove() instead which handles all of the logic > at once. > > Cc: Christoph Lameter > Cc: Pekka Enberg > Cc: David Rientjes > Cc: Joonsoo Kim > Cc: Andrew Morton > Cc: Vlastimil Babka > Cc: Roman Gushchin > Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Greg Kroah-Hartman Thanks, added to slab/for-6.3/fixes > --- > mm/slub.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/slub.c b/mm/slub.c > index 13459c69095a..4880e461fcc5 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -6449,7 +6449,7 @@ static void debugfs_slab_add(struct kmem_cache *s) > > void debugfs_slab_release(struct kmem_cache *s) > { > - debugfs_remove_recursive(debugfs_lookup(s->name, slab_debugfs_root)); > + debugfs_lookup_and_remove(s->name, slab_debugfs_root); > } > > static int __init slab_debugfs_init(void)