5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mikhail Lobanov <m.lobanov@xxxxxxxxxxxx>
commit a5e61b50c9f44c5edb6e134ede6fee8806ffafa9 upstream.
If the net_conf pointer is NULL and the code attempts to access its
fields without a check, it will lead to a null pointer dereference.
Add a NULL check before dereferencing the pointer.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 44ed167da748 ("drbd: rcu_read_lock() and rcu_dereference() for tconn->net_conf")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Mikhail Lobanov <m.lobanov@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240909133740.84297-1-m.lobanov@xxxxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/block/drbd/drbd_state.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/block/drbd/drbd_state.c
+++ b/drivers/block/drbd/drbd_state.c
@@ -876,7 +876,7 @@ is_valid_state(struct drbd_device *devic
ns.disk == D_OUTDATED)
rv = SS_CONNECTED_OUTDATES;
- else if ((ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T) &&
+ else if (nc && (ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T) &&
(nc->verify_alg[0] == 0))
rv = SS_NO_VERIFY_ALG;
