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b=YZ53phTqRYy50H9NdBl2+e6SCITiwm4R1hbz0W4awbu9Gyt/ZbaW0wmFqGd771/P3 qafFXo+1pFpMofv+4GBzjcHOs0aBa7hR1PgfrslTfDMlQmmR2gveO6uQ7iWE8z3RN1 zeNnjBheeKuuqgUgSDFoS1f5Rzs5cMTFBrWRsweiw4kbt6N/k7IUn4HN//xH2VXAdJ 72tDXn7BYd93Cv0SS+ZEin0lU1p7GuAlNR46X60zjWKTyfWuoOVZnZoFypHd8bALTJ AbjGcd48jpCMonjyTOu1gNJ9Q/VTlrENIc/iJ1hKdo1u2Ccpk85wPOx0mGnoEDz0ml a6Y4n/vRrHAVg== 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 6.6.y 1/2] mm/damon/sysfs: put target pids for damon_start() failure Date: Tue, 27 Oct 2026 21:59:00 -0700 Message-ID: <20261028045902.148624-2-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261028045902.148624-1-sj@kernel.org> References: <20261028045902.148624-1-sj@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: F11FBA0008 X-Stat-Signature: 17ppysfw76dsgkkbaftfwf1wgscx4t7u X-Rspam-User: 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-HE-Tag: 1793163551-662497 X-HE-Meta: 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 oA7bZkU7 /NYjCjNl/fh14QAFQZEkrRKJJoydPwEPEGmeSqiK3xte8RR0GHhIXL8O7z/RHtt5Dw5+1vPBIkmiuWRVmCRV7eCX5alIMYOJTmJ5fYEIIjfwnW14Ari7PuweTPe/xtLhwV/jNUO9a6cshuGGPwt+qRz28ERpFZMoT3G8eccugh/Av4CGocSomxjzBRFSgndpMorTJuKmiUwQAvTKvvjQW18N8lHiupcy9/R7HTgsUPs0fW0kMVGn0TkvEptvHZ7TF/WMTEBfxt7m9AnilcfFk7PFocw== 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 46980a4bef23a..d95fda1054a00 100644 --- a/mm/damon/sysfs.c +++ b/mm/damon/sysfs.c @@ -1465,6 +1465,7 @@ 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