From: David Miller <davem@davemloft.net>
To: arnd@arndb.de
Cc: kuznet@ms2.inr.ac.ru, yoshfuji@linux-ipv6.org,
edumazet@google.com, ncardwell@google.com, ycheng@google.com,
soheil@google.com, fw@strlen.de, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tcp: avoid bogus warning in tcp_clean_rtx_queue
Date: Tue, 19 Sep 2017 14:02:50 -0700 (PDT) [thread overview]
Message-ID: <20170919.140250.1393293793761020505.davem@davemloft.net> (raw)
In-Reply-To: <20170918204855.170920-1-arnd@arndb.de>
From: Arnd Bergmann <arnd@arndb.de>
Date: Mon, 18 Sep 2017 22:48:47 +0200
> gcc-4.9 warns that it cannot trace the state of the 'last_ackt'
> variable since the change to the TCP timestamping code, when
> CONFIG_PROFILE_ANNOTATED_BRANCHES is set:
>
> net/ipv4/tcp_input.c: In function 'tcp_clean_rtx_queue':
> include/net/tcp.h:757:23: error: 'last_ackt' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>
> Other gcc versions, both older and newer do now show this
> warning. Removing the 'likely' annotation makes it go away,
> and has no effect on the object code without
> CONFIG_PROFILE_ANNOTATED_BRANCHES, as tested with gcc-4.9
> and gcc-7.1.1, so this seems to be a safe workaround.
>
> Fixes: 9a568de4818d ("tcp: switch TCP TS option (RFC 7323) to 1ms clock")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This reaches the limits at which I am willing to work around compiler
stuff.
What cpu did you test the object code generation upon and does that
cpu have branch prediction hints in the target you are building for?
next prev parent reply other threads:[~2017-09-19 21:02 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-18 20:48 [PATCH] tcp: avoid bogus warning in tcp_clean_rtx_queue Arnd Bergmann
2017-09-19 21:02 ` David Miller [this message]
2017-09-19 21:32 ` Arnd Bergmann
2017-09-19 22:01 ` David Miller
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=20170919.140250.1393293793761020505.davem@davemloft.net \
--to=davem@davemloft.net \
--cc=arnd@arndb.de \
--cc=edumazet@google.com \
--cc=fw@strlen.de \
--cc=kuznet@ms2.inr.ac.ru \
--cc=linux-kernel@vger.kernel.org \
--cc=ncardwell@google.com \
--cc=netdev@vger.kernel.org \
--cc=soheil@google.com \
--cc=ycheng@google.com \
--cc=yoshfuji@linux-ipv6.org \
/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