Re: [PATCH net v8 6/6] net/sched: netem: check for negative latency and jitter

[Simon Horman]

On Fri, Apr 17, 2026 at 08:19:44PM -0700, Stephen Hemminger wrote:
> Reject requests with negative latency or jitter.
> A negative value added to current timestamp (u64) wraps
> to an enormous time_to_send, disabling dequeue.
> The original UAPI used u32 for these values; the conversion to 64-bit
> time values via TCA_NETEM_LATENCY64 and TCA_NETEM_JITTER64
> allowed signed values to reach the kernel without validation.
> 
> Jitter is already silently clamped by an abs() in netem_change();
> that abs() can be removed in a follow-up once this rejection is in
> place.
> 
> Fixes: 99803171ef04 ("netem: add uapi to express delay and jitter in nanoseconds")
> Signed-off-by: Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx>

Reviewed-by: Simon Horman <horms@xxxxxxxxxx>