[PATCH 5.12 250/296] net/smc: remove device from smcd_dev_list after failed device_add()

Greg Kroah-Hartman
2021-05-31T16:53:30Z

From: Julian Wiedmann <jwi@linux.ibm.com>

[ Upstream commit 444d7be9532dcfda8e0385226c862fd7e986f607 ]

If the device_add() for a smcd_dev fails, there's no cleanup step that
rolls back the earlier list_add(). The device subsequently gets freed,
and we end up with a corrupted list.

Add some error handling that removes the device from the list.

Fixes: c6ba7c9ba43d ("net/smc: add base infrastructure for SMC-D and ISM")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/smc/smc_ism.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/net/smc/smc_ism.c b/net/smc/smc_ism.c
index 94b31f2551bc..967712ba52a0 100644
--- a/net/smc/smc_ism.c
+++ b/net/smc/smc_ism.c
@@ -429,6 +429,8 @@ EXPORT_SYMBOL_GPL(smcd_alloc_dev);

int smcd_register_dev(struct smcd_dev *smcd)
{
+ int rc;
+
mutex_lock(&smcd_dev_list.mutex);
if (list_empty(&smcd_dev_list.list)) {
u8 *system_eid = NULL;
@@ -448,7 +450,14 @@ int smcd_register_dev(struct smcd_dev *smcd)
dev_name(&smcd->dev), smcd->pnetid,
smcd->pnetid_by_user ? " (user defined)" : "");

- return device_add(&smcd->dev);
+ rc = device_add(&smcd->dev);
+ if (rc) {
+ mutex_lock(&smcd_dev_list.mutex);
+ list_del(&smcd->list);
+ mutex_unlock(&smcd_dev_list.mutex);
+ }
+
+ return rc;
}
EXPORT_SYMBOL_GPL(smcd_register_dev);

--
2.30.2