powerpc/xive: Fix refcount leak in xive_spapr_init

JIRA: https://issues.redhat.com/browse/RHEL-80849

CVE: CVE-2022-49437

commit 1d1fb96
Author: Miaoqian Lin <[email protected]>
Date:   Thu May 12 13:05:33 2022 +0400

    powerpc/xive: Fix refcount leak in xive_spapr_init

    of_find_compatible_node() returns a node pointer with refcount
    incremented, we should use of_node_put() on it when done.
    Add missing of_node_put() to avoid refcount leak.

    Fixes: eac1e73 ("powerpc/xive: guest exploitation of the XIVE interrupt controller")
    Signed-off-by: Miaoqian Lin <[email protected]>
    Reviewed-by: Cédric Le Goater <[email protected]>
    Signed-off-by: Michael Ellerman <[email protected]>
    Link: https://lore.kernel.org/r/[email protected]

Signed-off-by: Mamatha Inamdar <[email protected]>

Author: Mamatha Inamdar

arch/powerpc/sysdev/xive/spapr.c

@@ -829,12 +829,12 @@ bool __init xive_spapr_init(void)
 	/* Resource 1 is the OS ring TIMA */
 	if (of_address_to_resource(np, 1, &r)) {
 		pr_err("Failed to get thread mgmnt area resource\n");
-		return false;
+		goto err_put;
 	}
 	tima = ioremap(r.start, resource_size(&r));
 	if (!tima) {
 		pr_err("Failed to map thread mgmnt area\n");
-		return false;
+		goto err_put;
 	}
 
 	if (!xive_get_max_prio(&max_prio))
@@ -870,13 +870,16 @@ bool __init xive_spapr_init(void)
 	if (!xive_core_init(np, &xive_spapr_ops, tima, TM_QW1_OS, max_prio))
 		goto err_mem_free;
 
+	of_node_put(np);
 	pr_info("Using %dkB queues\n", 1 << (xive_queue_shift - 10));
 	return true;
 
 err_mem_free:
 	xive_irq_bitmap_remove_all();
 err_unmap:
 	iounmap(tima);
+err_put:
+	of_node_put(np);
 	return false;
 }