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b=NgXk7PPolNc+ddHxBHO/mgGAh/tBkeEgp7YT5J9iFXmFKrlhUo5ziqe/cumMyS4UU h30NzbZc4IPcrQtD7B8w55ovJ+z3txhs0Jc+JGEakv8zX/UTYUA6/Awk3Bl9n0N1x8 0jg00kzDIlKlUlZnIi7uAYmONdjHRoEOwEqYIjA34rMGSTXMXCXBycFAUV7FPhc/9w mLxjE+NIK1JW0iEa6hGEAfBlwVi8VM/TtUm4YYhVcx3z4k6FdVu1tmORu0d6530YUv bulZbgwlSTAsX6ZbY5y54DaaBrejmA7iBOilYF+ujZOQin1o9iK6+6ni5Q0pPSuvbE z8oMaSrSmcHUQ== From: SJ Park To: Cc: SJ Park , stable@vger.kernel.org, Andrew Morton , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH 6.12.y 1/2] mm/damon/sysfs: put target pids for damon_start() failure Date: Tue, 27 Oct 2026 21:26:14 -0700 Message-ID: <20261028042617.165657-2-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261028042617.165657-1-sj@kernel.org> References: <20261028042617.165657-1-sj@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 07236A0006 X-Stat-Signature: dwznxef7bidqem4wbfyb8yjx8dgu6um8 X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Rspam-User: X-HE-Tag: 1793161587-81119 X-HE-Meta: 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 Jm45bzS2 HVDFswBweRSWsfojNEgarSVwNCRMgAVPNZE5fwpKUaKYnATHtTlwbAazlwgvWQO0pZACZFLlzKLnqLP0EPEPXrzcaBNGExuRKr+M70RWpHAqpIoIcOdSoKReJYZoPOCGJF8NqQoB6ZTA6kjvoLvL/J2UuIj7qXIjURoBiVMh705i0tbqbVkopuKvXDvEMtnzmge/gKMcU3Sy0LM1VjrywQ2sMK0mzu3ZWhVKrDCfi9cKBmklaE6kMyugBH/05PzI4Gp9p/i28qfcqciy4mpP1M6UuOg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 damon_sysfs_turn_damon_on() allocates and sets up damon_ctx to start. If it is for virtual address space monitoring, the setup increases the reference counts of the target pids. After the setup, the function invokes damon_start(). If damon_start() fails, it deallocates the damon_ctx object without decreasing the reference counts of target pids. As a result, pids can be leaked. Fix the leak by putting pids using damon_sysfs_destroy_targets() before deallocating the damon_ctx object. Fixes: a61ea561c871 ("mm/damon/sysfs: link DAMON for virtual address spaces monitoring") Cc: # 5.18.x Signed-off-by: SJ Park --- mm/damon/sysfs.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c index 5aa23c6545cb8..107a28557afe2 100644 --- a/mm/damon/sysfs.c +++ b/mm/damon/sysfs.c @@ -1519,6 +1519,7 @@ static int damon_sysfs_turn_damon_on(struct damon_sysfs_kdamond *kdamond) return PTR_ERR(ctx); err = damon_start(&ctx, 1, false); if (err) { + damon_sysfs_destroy_targets(ctx); damon_destroy_ctx(ctx); return err; } -- 2.47.3