netdev - Re: question on pktgen shutdown logic.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 22 May 2013 16:22:01 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Ben Greear <greearb@...delatech.com>
Cc:	netdev <netdev@...r.kernel.org>
Subject: Re: question on pktgen shutdown logic.

On Wed, 2013-05-22 at 16:15 -0700, Ben Greear wrote:
> While looking at pktgen.c in 3.9.3, I cannot explain how
> it does not race on shutdown.
> 
> The thread worker checks for pktgen_exiting, and will bail out
> of it's main loop and initiate cleanup if this is true.
> 
> The pg_net_exit sets the pktgen_exiting to true, and then
> proceedes to call
> 
> 		kthread_stop(t->tsk);
> 		kfree(t);
> 
> What I don't understand is what keeps the kfree(t) from happening
> before the thread has noticed pktgen_exiting is set and properly
> bailed out of it's loop and finished cleanup?

kthread_stop() is synchronous.



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html