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b=I9KbJE7qEqPtgy/TkRldcESI2Y5OZDrBs8NI88jwDvQ2YVPKxYjEw29qZpRZtjInw rcXln9rEdUnQynv6msdUInEVFzxX4kvlsE9GEnzU0cmw9B3W+5jDlollM0eCkdaigx 4Sp9MZA06d2kisL2q1wJWpZ3c0k6rc3rJZcogW6wg54ksbbA4rw2XSDxh8Jqc7lbSV Bma5ScdcjYOJaDvf7DQzUF23jT3//145nYk8ixnMCGFt4ydV+IB6xmXPg4wjJJj11y 2dmPfFlZeTWzPMC9cOiTrTtwkCe0IG7EPrl0eIsPXQS0O57C+SjYj4EDQt449wxS0d tFo6Oae4voYiQ== 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 6.1.y 1/2] mm/damon/sysfs: put target pids for damon_start() failure Date: Tue, 27 Oct 2026 22:11:02 -0700 Message-ID: <20261028051104.154232-2-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261028051104.154232-1-sj@kernel.org> References: <20261028051104.154232-1-sj@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 46F42180004 X-Stat-Signature: na4r8ranqc7msw11cbx8i8atauqt4ah5 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-Rspamd-Server: rspam09 X-HE-Tag: 1793164274-830616 X-HE-Meta: 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 G4g2Enkp pMNR1wREopNFcw6KdXjs2nb7yWWaaMHH8RQadZz9YkonEmfOSMlLaO0x+e750gxrC4G16SUrJgwmfck3FgPQ0SoUfMTkNP/rd3So0hkHacFz4ur2DBp9BvmsiEX9ZOAUpPVzGnp4UfYCu+gNzL6PrtC97NiErGVcfaxBD4qYNf+NLkPZZ2OjC63XlE0x/AocYN6D8wdfHBYuPcQud+eUXxlSnMYZSPOt6rk9x1YIQ/yE7b1Ii4HHuvHYzvvmMfVkNYuDX/cjYR1aZYUGI2ZYjq/DYoQ== 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 9a918f8e4c6bf..4b28bb9ba0a24 100644 --- a/mm/damon/sysfs.c +++ b/mm/damon/sysfs.c @@ -2547,6 +2547,7 @@ 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