From: Tonghao Zhang <xiangxia.m.yue@gmail.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: mattias.ronnblom@ericsson.com, dpdk-dev <dev@dpdk.org>, stable@dpdk.org
Subject: Re: [dpdk-dev] [PATCH dpdk-dev] rte_random: fix crash when random init
Date: Tue, 14 Apr 2020 12:43:47 +0800 [thread overview]
Message-ID: <CAMDZJNWKd7fs_+i6YpiMK2fufHZShP3W=54hFerC1dWw9eEsCg@mail.gmail.com> (raw)
In-Reply-To: <20200413210658.2308b86e@hermes.lan>
On Tue, Apr 14, 2020 at 12:07 PM Stephen Hemminger
<stephen@networkplumber.org> wrote:
>
> On Sun, 12 Apr 2020 16:27:53 +0800
> xiangxia.m.yue@gmail.com wrote:
>
> > From: Tonghao Zhang <xiangxia.m.yue@gmail.com>
> >
> > When rte_rand_init is invoked, and the kernel
> > (kernel version < 3.17) running dpdk does't support
> > *getentropy, at the same time, the cpu does't support
> > rdseed, the rte_rand_init will invoke rte_get_timer_cycles
> > which function will invoke rte_get_hpet_cycles
> > (RTE_LIBEAL_USE_HPET was enabled) while *eal_hpet is not
> > allocated.
> >
> > Fixes: faf8fd252785 ("eal: improve entropy for initial PRNG seed")
> > Fixes: 3f002f069612 ("eal: replace libc-based random generation with LFSR")
> >
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
>
> Are you sure this patch won't change current default to use HPET (which is slower)?
In rte_eal_timer_init (linux/eal_timer.c)， it will set
eal_timer_source = EAL_TIMER_TSC too.
So after rte_eal_init, eal_timer_source == EAL_TIMER_TSC which is the
default timer source actually.
Then this patch will affect RTE_INIT function which invoke
rte_get_timer_cycles. but hpet is not available yet.
> Before this patch users would get TSC as default.
--
Best regards, Tonghao
next prev parent reply other threads:[~2020-04-14 4:44 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-12 8:27 xiangxia.m.yue
2020-04-14 4:06 ` Stephen Hemminger
2020-04-14 4:43 ` Tonghao Zhang [this message]
2020-04-14 13:19 ` Mattias Rönnblom
2020-04-14 13:35 ` David Marchand
2020-04-14 15:37 ` Mattias Rönnblom
2020-04-14 23:42 ` Tonghao Zhang
2020-04-15 6:01 ` Mattias Rönnblom
2020-04-15 8:10 ` David Marchand
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