linux-kernel - [PATCH v2 1/5] bootconfig: Fix to check the xbc

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Date:   Wed, 15 Sep 2021 09:53:06 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Mike Rapoport <rppt@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Linux-MM <linux-mm@...ck.org>, Vlastimil Babka <vbabka@...e.cz>
Subject: [PATCH v2 1/5] bootconfig: Fix to check the xbc_node is used before free it

Fix to check the xbc_node is used before calling memblock_free()
because passing NULL to phys_addr() will cause a panic.
This will happen if user doesn't pass any bootconfig to the
kernel, because kernel will call xbc_destroy_all() after
booting.

Fixes: 40caa127f3c7 ("init: bootconfig: Remove all bootconfig data when the init memory is removed")
Reported-by: kernel test robot <oliver.sang@...el.com>
Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
---
 Changes in v2:
   - Rebase on top of Linus tree.
---
 lib/bootconfig.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/bootconfig.c b/lib/bootconfig.c
index 5ae248b29373..bee691ea8213 100644
--- a/lib/bootconfig.c
+++ b/lib/bootconfig.c
@@ -792,7 +792,8 @@ void __init xbc_destroy_all(void)
 	xbc_data = NULL;
 	xbc_data_size = 0;
 	xbc_node_num = 0;
-	memblock_free_ptr(xbc_nodes, sizeof(struct xbc_node) * XBC_NODE_MAX);
+	if (xbc_nodes)
+		memblock_free_ptr(xbc_nodes, sizeof(struct xbc_node) * XBC_NODE_MAX);
 	xbc_nodes = NULL;
 	brace_index = 0;
 }