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([2001:250:5800:1000::f280]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-38e17443f4fsm1399012a91.11.2026.07.14.05.15.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Jul 2026 05:15:06 -0700 (PDT) From: Guangshuo Li To: Borislav Petkov , Tony Luck , Qiushi Wu , linux-edac@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Guangshuo Li Subject: [PATCH] EDAC/device: Fix double free on sysfs registration failure Date: Tue, 14 Jul 2026 20:11:13 +0800 Message-ID: <20260714121113.1488956-1-lgs201920130244@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" edac_device_alloc_ctl_info() allocates dev_ctl and passes it to edac_device_register_sysfs_main_kobj() to initialize its embedded kobject. If kobject_init_and_add() fails, the helper calls kobject_put(). The final reference invokes edac_device_ctrl_master_release(), which calls __edac_device_free_ctl_info() and frees dev_ctl for the first time. After the helper returns an error, edac_device_alloc_ctl_info() jumps to its free label and calls __edac_device_free_ctl_info() on the same object again, resulting in a double free. The helper also accesses edac_dev after kobject_put() may already have freed it. Make the registration helper release edac_dev on every failure path and return directly from the allocator when registration fails. Avoid accessing the object after kobject_put() transfers cleanup to the release callback. This issue was found by a static analysis tool I am developing. Fixes: 17ed808ad243 ("EDAC: Fix reference count leaks") Signed-off-by: Guangshuo Li --- drivers/edac/edac_device.c | 2 +- drivers/edac/edac_device_sysfs.c | 20 +++++++++++++------- 2 files changed, 14 insertions(+), 8 deletions(-) diff --git a/drivers/edac/edac_device.c b/drivers/edac/edac_device.c index cf0d3c2dfc04..ce986dc341cb 100644 --- a/drivers/edac/edac_device.c +++ b/drivers/edac/edac_device.c @@ -133,7 +133,7 @@ edac_device_alloc_ctl_info(unsigned pvt_sz, char *dev_n= ame, unsigned nr_instance */ err =3D edac_device_register_sysfs_main_kobj(dev_ctl); if (err) - goto free; + return NULL; =20 /* at this point, the root kobj is valid, and in order to * 'free' the object, then the function: diff --git a/drivers/edac/edac_device_sysfs.c b/drivers/edac/edac_device_sy= sfs.c index b1c2717cd023..acab6c07f304 100644 --- a/drivers/edac/edac_device_sysfs.c +++ b/drivers/edac/edac_device_sysfs.c @@ -247,15 +247,17 @@ int edac_device_register_sysfs_main_kobj(struct edac_= device_ctl_info *edac_dev) edac_dev->owner =3D THIS_MODULE; =20 if (!try_module_get(edac_dev->owner)) - goto err_out; + goto free_ctl_info; =20 /* register */ dev_root =3D bus_get_dev_root(edac_subsys); - if (dev_root) { - err =3D kobject_init_and_add(&edac_dev->kobj, &ktype_device_ctrl, - &dev_root->kobj, "%s", edac_dev->name); - put_device(dev_root); - } + if (!dev_root) + goto module_put; + + err =3D kobject_init_and_add(&edac_dev->kobj, &ktype_device_ctrl, + &dev_root->kobj, "%s", edac_dev->name); + put_device(dev_root); + if (err) { edac_dbg(1, "Failed to register '.../edac/%s'\n", edac_dev->name); @@ -274,9 +276,13 @@ int edac_device_register_sysfs_main_kobj(struct edac_d= evice_ctl_info *edac_dev) /* Error exit stack */ err_kobj_reg: kobject_put(&edac_dev->kobj); + return err; + +module_put: module_put(edac_dev->owner); =20 -err_out: +free_ctl_info: + __edac_device_free_ctl_info(edac_dev); return err; } =20 --=20 2.43.0