[PATCH net] dibs: fix double free of dmb_clientid_arr

[Hidayath Khan]

dibs_dev_add() frees dibs->dmb_clientid_arr on both of its failure
paths, but does not clear the pointer. dibs_lo_dev_probe() then frees
the same pointer again in its err_reg path, so a failing device_add()
or sysfs_create_group() results in a double free.

Drop the kfree() from dibs_lo_dev_probe().

Note: commit cc21191b584c ("dibs: Move data path to dibs layer") moved
the code to its current location; the race was introduced earlier by
commit c3a910f2380f ("net/smc: implement DMB-merged operations of
loopback-ism").

Fixes: c3a910f2380f ("net/smc: implement DMB-merged operations of loopback-ism")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Alexandra Winter <wintera@xxxxxxxxxxxxx>
Signed-off-by: Hidayath Khan <hidayath@xxxxxxxxxxxxx>
---
 drivers/dibs/dibs_loopback.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/dibs/dibs_loopback.c b/drivers/dibs/dibs_loopback.c
index fd5caf1e19a8..649e4e375be3 100644
--- a/drivers/dibs/dibs_loopback.c
+++ b/drivers/dibs/dibs_loopback.c
@@ -335,7 +335,6 @@ static int dibs_lo_dev_probe(void)
 	return 0;
 
 err_reg:
-	kfree(dibs->dmb_clientid_arr);
 	/* pairs with dibs_dev_alloc() */
 	put_device(&dibs->dev);
 	kfree(ldev);

base-commit: 98379cf6109c0adb5879f86ba3efd4afe389a64a
prerequisite-patch-id: da145e40ff1ce22e9701dd49676606f612c03872
-- 
2.52.0