On Wed, Oct 4, 2023 at 12:32 PM Tejun Heo <tj@xxxxxxxxxx> wrote: > > Hello, > > On Thu, Sep 28, 2023 at 09:58:58AM +0800, linan666@xxxxxxxxxxxxxxx wrote: > > From: Li Nan <linan122@xxxxxxxxxx> > > > > When the throttle of bps is not enabled, tg_bps_limit() returns U64_MAX, > > which is be used in calculate_bytes_allowed(), and divide 0 error will > > happen. > > calculate_bytes_allowed() is just > > return mul_u64_u64_div_u64(bps_limit, (u64)jiffy_elapsed, (u64)HZ); > > The only division is by HZ. How does divide by 0 happen? We've also noticed this - haven't looked too deeply but I don't think it's a divide by zero, but an overflow (bps_limit * jiffy_elapsed / HZ will overflow for jiffies > HZ). mul_u64_u64_div_u64 does say it will throw DE if the mul overflows > > Thanks. > > -- > tejun
