Re: [PATCH net-next 2/3] tcp_hybla: fix divide by zero on rtt0 == 0
From: Eric Dumazet <hidden>
Date: 2026-09-30 11:24:02
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On Wed, Sep 30, 2026 at 12:10 PM Jiayuan Chen [off-list ref] wrote:
rtt0 is the reference RTT in ms, so 0 makes no sense, and
hybla_recalc_param() divides by it right from hybla_init().
Reject values below 1 when the parameter is written. Also cap it at
U32_MAX / USEC_PER_MSEC, since rtt0 * USEC_PER_MSEC can wrap to 0 on
32-bit. An rtt0 above that (about 71 minutes) makes no sense anyway.
Fixes: 835b3f0c0d7e ("[TCP]: Add TCP Hybla congestion control module.")
Fixes: 740b0f1841f6 ("tcp: switch rtt estimations to usec resolution")
Reported-by: VEGA <redacted>
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
---Reviewed-by: Eric Dumazet <edumazet@kernel.org>