From: "Mattias Rönnblom" <hofors@lysator.liu.se>
To: Stephen Hemminger <stephen@networkplumber.org>,
David Marchand <david.marchand@redhat.com>
Cc: dev@dpdk.org, thomas@monjalon.net, frode.nordahl@canonical.com,
mattias.ronnblom@ericsson.com, anatoly.burakov@intel.com,
stable@dpdk.org, "Tyler Retzlaff" <roretzla@linux.microsoft.com>,
"Bruce Richardson" <bruce.richardson@intel.com>,
"Dmitry Kozlyuk" <dmitry.kozliuk@gmail.com>,
"Chengwen Feng" <fengchengwen@huawei.com>,
"Morten Brørup" <mb@smartsharesystems.com>,
"Konstantin Ananyev" <konstantin.ananyev@huawei.com>
Subject: Re: [PATCH v2 2/5] random: defer seeding to EAL init
Date: Wed, 18 Dec 2024 18:03:06 +0100 [thread overview]
Message-ID: <45bc0287-8916-4c84-a0d8-5bc4ad2faed1@lysator.liu.se> (raw)
In-Reply-To: <20241218083502.266cd066@hermes.local>
On 2024-12-18 17:35, Stephen Hemminger wrote:
> On Tue, 17 Dec 2024 09:59:49 +0100
> David Marchand <david.marchand@redhat.com> wrote:
>
>> The RNG is documented as being seeded as part of EAL init.
>>
>> Move the initialisation (seeding) helper out of a constructor and
>> call it explicitly from rte_eal_init() as it was done before commit
>> 3f002f069612 ("eal: replace libc-based random generation with LFSR").
>>
>> This also moves the unconditional lcore variable allocation out of a
>> constructor.
>>
>> While at it, mark local symbol rand_state as static.
>>
>> Fixes: 29c39cd3d54d ("random: keep PRNG state in lcore variable")
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: David Marchand <david.marchand@redhat.com>
>> Reviewed-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
>> Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
>
> Probably need to add a check to rte_random() so it crashes
> if called before initialization, rather than returning an un-random
> number which could be a hidden long term bug.
If you do, do it either as a RTE_ASSERT() or an RTE_VERIFY() in the
(lcore_id == LCORE_ID_ANY) path, since that is what will be taken.
Preferably, you should have as little as possible in rte_rand() fast
path, because this function is used in packet processing.
That said, the "unrandom" number will always be 0, so it shouldn't go
unnoticed for too long.
next prev parent reply other threads:[~2024-12-18 17:03 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-05 17:57 [PATCH 0/3] Defer lcore variables allocation David Marchand
2024-12-05 17:57 ` [PATCH 1/3] random: defer seeding to EAL init David Marchand
2024-12-06 11:09 ` Mattias Rönnblom
2024-12-16 9:38 ` Burakov, Anatoly
2024-12-05 17:57 ` [PATCH 2/3] power: defer lcore variable allocation David Marchand
2024-12-06 11:29 ` Mattias Rönnblom
2024-12-12 7:57 ` David Marchand
2024-12-13 6:58 ` Mattias Rönnblom
2024-12-16 10:02 ` David Marchand
2024-12-05 17:57 ` [PATCH 3/3] eal/x86: defer power intrinsics " David Marchand
2024-12-06 11:32 ` Mattias Rönnblom
2024-12-06 11:01 ` [PATCH 0/3] Defer lcore variables allocation Mattias Rönnblom
2024-12-06 15:55 ` Thomas Monjalon
2024-12-10 17:09 ` Stephen Hemminger
2024-12-09 11:03 ` David Marchand
2024-12-09 15:39 ` Mattias Rönnblom
2024-12-09 17:40 ` David Marchand
2024-12-10 9:41 ` Mattias Rönnblom
2024-12-16 10:01 ` Burakov, Anatoly
2024-12-16 9:42 ` Burakov, Anatoly
2024-12-16 9:49 ` David Marchand
2024-12-17 9:06 ` David Marchand
2024-12-18 20:10 ` Mattias Rönnblom
2024-12-17 8:59 ` [PATCH v2 0/5] " David Marchand
2024-12-17 8:59 ` [PATCH v2 1/5] eal: check lcore variable handle David Marchand
2024-12-18 11:18 ` Burakov, Anatoly
2024-12-17 8:59 ` [PATCH v2 2/5] random: defer seeding to EAL init David Marchand
2024-12-18 16:35 ` Stephen Hemminger
2024-12-18 17:03 ` Mattias Rönnblom [this message]
2024-12-17 8:59 ` [PATCH v2 3/5] power: defer lcore variable allocation David Marchand
2024-12-18 11:17 ` Burakov, Anatoly
2024-12-17 8:59 ` [PATCH v2 4/5] power: reduce memory footprint of per-lcore state David Marchand
2024-12-18 11:17 ` Burakov, Anatoly
2024-12-17 8:59 ` [PATCH v2 5/5] eal/x86: defer power intrinsics variable allocation David Marchand
2024-12-18 11:17 ` Burakov, Anatoly
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=45bc0287-8916-4c84-a0d8-5bc4ad2faed1@lysator.liu.se \
--to=hofors@lysator.liu.se \
--cc=anatoly.burakov@intel.com \
--cc=bruce.richardson@intel.com \
--cc=david.marchand@redhat.com \
--cc=dev@dpdk.org \
--cc=dmitry.kozliuk@gmail.com \
--cc=fengchengwen@huawei.com \
--cc=frode.nordahl@canonical.com \
--cc=konstantin.ananyev@huawei.com \
--cc=mattias.ronnblom@ericsson.com \
--cc=mb@smartsharesystems.com \
--cc=roretzla@linux.microsoft.com \
--cc=stable@dpdk.org \
--cc=stephen@networkplumber.org \
--cc=thomas@monjalon.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).