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([2402:f000:4:1006:809:ffff:fffe:18ea]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-29dae4a13d2sm173364705ad.9.2025.12.09.23.41.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Dec 2025 23:41:28 -0800 (PST) From: Tuo Li To: song@kernel.org, yukuai@fnnas.com Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, Tuo Li Subject: [PATCH] md/raid5: fix possible null-pointer dereferences in raid5_store_group_thread_cnt() Date: Wed, 10 Dec 2025 15:41:12 +0800 Message-ID: <20251210074112.3975053-1-islituo@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The variable mddev->private is first assigned to conf and then checked: conf =3D mddev->private; if (!conf) ... If conf is NULL, then mddev->private is also NULL. However, the function does not return at this point, and raid5_quiesce() is later called with mddev as the argument. Inside raid5_quiesce(), mddev->private is again assigned to conf, which is then dereferenced in multiple places, for example: conf->quiesce =3D 0; wake_up(&conf->wait_for_quiescent); ... This can lead to several null-pointer dereferences. To fix these issues, the function should unlock mddev and return early when conf is NULL, following the pattern in raid5_change_consistency_policy(). Signed-off-by: Tuo Li --- drivers/md/raid5.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index e57ce3295292..be3f9a127212 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -7190,9 +7190,10 @@ raid5_store_group_thread_cnt(struct mddev *mddev, co= nst char *page, size_t len) raid5_quiesce(mddev, true); =20 conf =3D mddev->private; - if (!conf) - err =3D -ENODEV; - else if (new !=3D conf->worker_cnt_per_group) { + if (!conf) { + mddev_unlock_and_resume(mddev); + return -ENODEV; + } else if (new !=3D conf->worker_cnt_per_group) { old_groups =3D conf->worker_groups; if (old_groups) flush_workqueue(raid5_wq); --=20 2.43.0