| Date | Mon, 1 Jun 2020 22:59:39 +0200 | From | Pavel Machek <> | Subject | Re: [PATCH 4.19 10/95] net sched: fix reporting the first-time use timestamp |
| |
Hi!
On Mon 2020-06-01 19:53:10, Greg Kroah-Hartman wrote: > From: Roman Mashak <mrv@mojatatu.com> > > [ Upstream commit b15e62631c5f19fea9895f7632dae9c1b27fe0cd ] > > When a new action is installed, firstuse field of 'tcf_t' is explicitly set > to 0. Value of zero means "new action, not yet used"; as a packet hits the > action, 'firstuse' is stamped with the current jiffies value. > > tcf_tm_dump() should return 0 for firstuse if action has not yet been hit. > > Fixes: 48d8ee1694dd ("net sched actions: aggregate dumping of actions timeinfo")
Jiffies start at small negative value (and are expected to overflow periodically). This code will not work correctly in that case.
Best regards, Pavel
> +++ b/include/net/act_api.h > @@ -67,7 +67,8 @@ static inline void tcf_tm_dump(struct tc > { > dtm->install = jiffies_to_clock_t(jiffies - stm->install); > dtm->lastuse = jiffies_to_clock_t(jiffies - stm->lastuse); > - dtm->firstuse = jiffies_to_clock_t(jiffies - stm->firstuse); > + dtm->firstuse = stm->firstuse ? > + jiffies_to_clock_t(jiffies - stm->firstuse) : 0; > dtm->expires = jiffies_to_clock_t(stm->expires); > } > >
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