4.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx> commit 45c2fdde01299b02a6e3225e848598a3c1e55539 upstream. Commit 383212425c926 ("hwrng: omap - Add device variant for SafeXcel IP-76 found in Armada 8K") added support for the SafeXcel IP-76 variant of the IP. This modification included getting a reference and enabling a clock. Unfortunately, this was done *after* writing to the RNG_INTMASK_REG register. This generally works fine when the driver is built-in because the clock might have been left enabled by the bootloader, but fails short when the driver is built as a module: it causes a system hang because a register is being accessed while the clock is not enabled. This commit fixes that by making the register access *after* enabling the clock. This issue was found by the kernelci.org testing effort. Fixes: 383212425c926 ("hwrng: omap - Add device variant for SafeXcel IP-76 found in Armada 8K") Signed-off-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx> Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/char/hw_random/omap-rng.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/char/hw_random/omap-rng.c +++ b/drivers/char/hw_random/omap-rng.c @@ -397,7 +397,6 @@ static int of_get_omap_rng_device_detail irq, err); return err; } - omap_rng_write(priv, RNG_INTMASK_REG, RNG_SHUTDOWN_OFLO_MASK); priv->clk = of_clk_get(pdev->dev.of_node, 0); if (IS_ERR(priv->clk) && PTR_ERR(priv->clk) == -EPROBE_DEFER) @@ -408,6 +407,8 @@ static int of_get_omap_rng_device_detail dev_err(&pdev->dev, "unable to enable the clk, " "err = %d\n", err); } + + omap_rng_write(priv, RNG_INTMASK_REG, RNG_SHUTDOWN_OFLO_MASK); } return 0; }