clk: fix a panic error caused by accessing NULL pointer

[ Upstream commit 975b820b6836b6b6c42fb84cd2e772e2b41bca67 ]

In some cases the clock parent would be set NULL when doing re-parent,
it will cause a NULL pointer accessing if clk_set trace event is
enabled.

This patch sets the parent as "none" if the input parameter is NULL.

Fixes: dfc202ead312 (clk: Add tracepoints for hardware operations)
Signed-off-by: Cai Li <cai.li@spreadtrum.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/trace/events/clk.h b/include/trace/events/clk.h
index 7586072..2cd4493 100644 (file)
--- a/include/trace/events/clk.h
+++ b/include/trace/events/clk.h
@@ -134,12 +134,12 @@ DECLARE_EVENT_CLASS(clk_parent,
 
        TP_STRUCT__entry(
                __string(        name,           core->name                )
-               __string(        pname,          parent->name              )
+               __string(        pname, parent ? parent->name : "none"     )
        ),
 
        TP_fast_assign(
                __assign_str(name, core->name);
-               __assign_str(pname, parent->name);
+               __assign_str(pname, parent ? parent->name : "none");
        ),
 
        TP_printk("%s %s", __get_str(name), __get_str(pname))