From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
To: Xin Long <lucien.xin@gmail.com>
Cc: network dev <netdev@vger.kernel.org>,
linux-sctp@vger.kernel.org, davem@davemloft.net,
Eric Dumazet <edumazet@google.com>,
Neil Horman <nhorman@tuxdriver.com>
Subject: Re: [PATCHv2 net] sctp: not disable bh in the whole sctp_get_port_local()
Date: Fri, 21 Aug 2020 20:07:04 +0000 [thread overview]
Message-ID: <20200821200704.GM3399@localhost.localdomain> (raw)
In-Reply-To: <08a14c2f087153c18c67965cc37ed2ac22da18ed.1597993178.git.lucien.xin@gmail.com>
On Fri, Aug 21, 2020 at 02:59:38PM +0800, Xin Long wrote:
> With disabling bh in the whole sctp_get_port_local(), when
> snum = 0 and too many ports have been used, the do-while
> loop will take the cpu for a long time and cause cpu stuck:
>
> [ ] watchdog: BUG: soft lockup - CPU#11 stuck for 22s!
> [ ] RIP: 0010:native_queued_spin_lock_slowpath+0x4de/0x940
> [ ] Call Trace:
> [ ] _raw_spin_lock+0xc1/0xd0
> [ ] sctp_get_port_local+0x527/0x650 [sctp]
> [ ] sctp_do_bind+0x208/0x5e0 [sctp]
> [ ] sctp_autobind+0x165/0x1e0 [sctp]
> [ ] sctp_connect_new_asoc+0x355/0x480 [sctp]
> [ ] __sctp_connect+0x360/0xb10 [sctp]
>
> There's no need to disable bh in the whole function of
> sctp_get_port_local. So fix this cpu stuck by removing
> local_bh_disable() called at the beginning, and using
> spin_lock_bh() instead.
>
> The same thing was actually done for inet_csk_get_port() in
> Commit ea8add2b1903 ("tcp/dccp: better use of ephemeral
> ports in bind()").
>
> Thanks to Marcelo for pointing the buggy code out.
>
> v1->v2:
> - use cond_resched() to yield cpu to other tasks if needed,
> as Eric noticed.
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
next prev parent reply other threads:[~2020-08-21 20:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-21 6:59 [PATCHv2 net] sctp: not disable bh in the whole sctp_get_port_local() Xin Long
2020-08-21 20:07 ` Marcelo Ricardo Leitner [this message]
2020-08-24 22:51 ` 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=20200821200704.GM3399@localhost.localdomain \
--to=marcelo.leitner@gmail.com \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=linux-sctp@vger.kernel.org \
--cc=lucien.xin@gmail.com \
--cc=netdev@vger.kernel.org \
--cc=nhorman@tuxdriver.com \
/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).