4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mikhail Lobanov m.lobanov@rosalinux.ru
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@vger.kernel.org Signed-off-by: Mikhail Lobanov m.lobanov@rosalinux.ru Link: https://lore.kernel.org/r/20240909133740.84297-1-m.lobanov@rosalinux.ru Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 @@ -888,7 +888,7 @@ 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;