On 07/10/2024 10:54, Dan Carpenter wrote:
On Mon, Oct 07, 2024 at 09:48:40AM +0100, Colin Ian King wrote:The calculation of fout is using int multiplication and assigning the result to a u64, this can potentially overflow if the int variable mdiv is too large. Fix this by making the 65536 a u64 value to ensure a u64 multiplication is being performed to avoid the overflow. Fixes: 53990cf9d5b4 ("clk: imx: pll14xx: consolidate rate calculation") Signed-off-by: Colin Ian King <colin.i.king@xxxxxxxxx>mdiv is always clamped in then 0-1023 range by one of these: mdiv = FIELD_GET(MDIV_MASK, pll_div_ctl0); mdiv = clamp(mdiv, 64, 1023); so it can't overflow and the Fixes tag is unnecessary.
Good point.
I think the reason why "fout" is declared as a u64 is because we were worried that on 32 bit systems the "fout *=" operation could overflow. That looks reasonable to me.
Yes, that makes perfect sense. NAK my patch. Apologies for the noise. Colin
regards, dan carpenter
