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From:   Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
To:     Borislav Petkov <bp@alien8.de>, Tony Luck <tony.luck@intel.com>,
        James Morse <james.morse@arm.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Robert Richter <rric@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-edac@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     dan.carpenter@linaro.org, kernel-janitors@vger.kernel.org,
        error27@gmail.com, harshit.m.mogalapalli@oracle.com
Subject: [PATCH] EDAC/sysfs: Fix calling kobject_put() without kobj initialization
Date:   Tue, 28 Nov 2023 05:09:52 -0800
Message-ID: <20231128130952.3372794-1-harshit.m.mogalapalli@oracle.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

In edac_pci_main_kobj_setup() when dev_root is NULL,
kobject_init_and_add() is not called.

        if (err) { // err = -ENODEV;
                edac_dbg(1, "Failed to register '.../edac/pci'\n");
                goto kobject_init_and_add_fail; // call to kobject_put()
        }

This will cause a runtime warning in kobject_put() if the above happens.
Warning:
"kobject: '%s' (%p): is not initialized, yet kobject_put() is being called."

Fix the error handling to avoid the above possible situation.

Fixes: cb4a0bec0bb9 ("EDAC/sysfs: move to use bus_get_dev_root()")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
---
This is based on static analysis with Smatch and only compile tested.
---
 drivers/edac/edac_pci_sysfs.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/edac/edac_pci_sysfs.c b/drivers/edac/edac_pci_sysfs.c
index 901d4cd3ca38..71a0d4b9c2cf 100644
--- a/drivers/edac/edac_pci_sysfs.c
+++ b/drivers/edac/edac_pci_sysfs.c
@@ -370,12 +370,14 @@ static int edac_pci_main_kobj_setup(void)
 
 	/* Instanstiate the pci object */
 	dev_root = bus_get_dev_root(edac_subsys);
-	if (dev_root) {
-		err = kobject_init_and_add(edac_pci_top_main_kobj,
-					   &ktype_edac_pci_main_kobj,
-					   &dev_root->kobj, "pci");
-		put_device(dev_root);
-	}
+	if (!dev_root)
+		goto kzalloc_fail;
+
+	err = kobject_init_and_add(edac_pci_top_main_kobj,
+				   &ktype_edac_pci_main_kobj,
+				   &dev_root->kobj, "pci");
+	put_device(dev_root);
+
 	if (err) {
 		edac_dbg(1, "Failed to register '.../edac/pci'\n");
 		goto kobject_init_and_add_fail;
-- 
2.39.3