This is a note to let you know that I've just added the patch titled firmware: arm_scpi: Prevent the ternary sign expansion bug to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: firmware-arm_scpi-prevent-the-ternary-sign-expansion.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 4642d93c0ef0092eab1aa1bbab16b0693e3809d3 Author: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Date: Thu Apr 22 12:02:29 2021 +0300 firmware: arm_scpi: Prevent the ternary sign expansion bug [ Upstream commit d9cd78edb2e6b7e26747c0ec312be31e7ef196fe ] How the type promotion works in ternary expressions is a bit tricky. The problem is that scpi_clk_get_val() returns longs, "ret" is a int which holds a negative error code, and le32_to_cpu() is an unsigned int. We want the negative error code to be cast to a negative long. But because le32_to_cpu() is an u32 then "ret" is type promoted to u32 and becomes a high positive and then it is promoted to long and it is still a high positive value. Fix this by getting rid of the ternary. Link: https://lore.kernel.org/r/YIE7pdqV/h10tEAK@mwanda Fixes: 8cb7cf56c9fe ("firmware: add support for ARM System Control and Power Interface(SCPI) protocol") Reviewed-by: Cristian Marussi <cristian.marussi@xxxxxxx> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> [sudeep.holla: changed to return 0 as clock rate on error] Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/firmware/arm_scpi.c b/drivers/firmware/arm_scpi.c index d0dee37ad522..4ceba5ef7895 100644 --- a/drivers/firmware/arm_scpi.c +++ b/drivers/firmware/arm_scpi.c @@ -552,8 +552,10 @@ static unsigned long scpi_clk_get_val(u16 clk_id) ret = scpi_send_message(CMD_GET_CLOCK_VALUE, &le_clk_id, sizeof(le_clk_id), &rate, sizeof(rate)); + if (ret) + return 0; - return ret ? ret : le32_to_cpu(rate); + return le32_to_cpu(rate); } static int scpi_clk_set_val(u16 clk_id, unsigned long rate)