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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, "Greg Kroah-Hartman" <greg@kroah.com>,
        "Bjorn Helgaas" <bhelgaas@google.com>,
        "Lukas Wunner" <lukas@wunner.de>
Date:   Sun, 09 Dec 2018 21:50:33 +0000
Message-ID: <lsq.1544392233.569368809@decadent.org.uk>
Subject: [PATCH 3.16 050/328] PCI: hotplug: Don't leak pci_slot on
 registration failure
In-Reply-To: <lsq.1544392232.713909046@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.62-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Lukas Wunner <lukas@wunner.de>

commit 4ce6435820d1f1cc2c2788e232735eb244bcc8a3 upstream.

If addition of sysfs files fails on registration of a hotplug slot, the
struct pci_slot as well as the entry in the slot_list is leaked.  The
issue has been present since the hotplug core was introduced in 2002:
https://git.kernel.org/tglx/history/c/a8a2069f432c

Perhaps the idea was that even though sysfs addition fails, the slot
should still be usable.  But that's not how drivers use the interface,
they abort probe if a non-zero value is returned.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/pci/hotplug/pci_hotplug_core.c | 9 +++++++++
 1 file changed, 9 insertions(+)

--- a/drivers/pci/hotplug/pci_hotplug_core.c
+++ b/drivers/pci/hotplug/pci_hotplug_core.c
@@ -457,8 +457,17 @@ int __pci_hp_register(struct hotplug_slo
 	list_add(&slot->slot_list, &pci_hotplug_slot_list);
 
 	result = fs_add_slot(pci_slot);
+	if (result)
+		goto err_list_del;
+
 	kobject_uevent(&pci_slot->kobj, KOBJ_ADD);
 	dbg("Added slot %s to the list\n", name);
+	goto out;
+
+err_list_del:
+	list_del(&slot->slot_list);
+	pci_slot->hotplug = NULL;
+	pci_destroy_slot(pci_slot);
 out:
 	mutex_unlock(&pci_hp_mutex);
 	return result;