[ Upstream commit e97fe4901e0f59a0bfd524578fe3768f8ca42428 ]
It is possible for clk_core_get to dereference a NULL in the following
sequence:
clk_core_get()
of_clk_get_hw_from_clkspec()
__of_clk_get_hw_from_provider()
__clk_get_hw()
__clk_get_hw() can return NULL which is dereferenced by clk_core_get() at
hw->core.
Prior to commit dde4eff47c82 ("clk: Look for parents with clkdev based
clk_lookups") the check IS_ERR_OR_NULL() was performed which would have
caught the NULL.
Reading the description of this function it talks about returning NULL but
that cannot be so at the moment.
Update the function to check for hw before dereferencing it and return NULL
if hw is NULL.
Fixes: dde4eff47c82 ("clk: Look for parents with clkdev based clk_lookups")
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Link: https://lore.kernel.org/r/20240302-linux-next-24-03-01-simple-clock-fixes-v1-1-25f348a5982b@linaro.org
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
