5.4-stable review patch. If anyone has any objections, please let me know.
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From: Alessandro Carminati alessandro.carminati@gmail.com
commit ceb87a361d0b079ecbc7d2831618c19087f304a9 upstream.
In the possible_parent_show function, ensure proper handling of the return value from of_clk_get_parent_name to prevent potential issues arising from a NULL return. The current implementation invokes seq_puts directly on the result of of_clk_get_parent_name without verifying the return value, which can lead to kernel panic if the function returns NULL.
This patch addresses the concern by introducing a check on the return value of of_clk_get_parent_name. If the return value is not NULL, the function proceeds to call seq_puts, providing the returned value as argument. However, if of_clk_get_parent_name returns NULL, the function provides a static string as argument, avoiding the panic.
Fixes: 1ccc0ddf046a ("clk: Use seq_puts() in possible_parent_show()") Reported-by: Philip Daly pdaly@redhat.com Signed-off-by: Alessandro Carminati (Red Hat) alessandro.carminati@gmail.com Link: https://lore.kernel.org/r/20230921073217.572151-1-alessandro.carminati@gmail... Signed-off-by: Stephen Boyd sboyd@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/clk/clk.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-)
--- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -3080,6 +3080,7 @@ static void possible_parent_show(struct unsigned int i, char terminator) { struct clk_core *parent; + const char *name = NULL;
/* * Go through the following options to fetch a parent's name. @@ -3094,18 +3095,20 @@ static void possible_parent_show(struct * registered (yet). */ parent = clk_core_get_parent_by_index(core, i); - if (parent) + if (parent) { seq_puts(s, parent->name); - else if (core->parents[i].name) + } else if (core->parents[i].name) { seq_puts(s, core->parents[i].name); - else if (core->parents[i].fw_name) + } else if (core->parents[i].fw_name) { seq_printf(s, "<%s>(fw)", core->parents[i].fw_name); - else if (core->parents[i].index >= 0) - seq_puts(s, - of_clk_get_parent_name(core->of_node, - core->parents[i].index)); - else - seq_puts(s, "(missing)"); + } else { + if (core->parents[i].index >= 0) + name = of_clk_get_parent_name(core->of_node, core->parents[i].index); + if (!name) + name = "(missing)"; + + seq_puts(s, name); + }
seq_putc(s, terminator); }