netdev - Re: [PATCH] kref: add function for reading kref value

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:	Mon, 12 Dec 2011 18:42:34 +0100
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Daniel Baluta <dbaluta@...acom.com>
Cc:	Greg KH <greg@...ah.com>, linux-kernel@...r.kernel.org,
	netdev@...r.kernel.org, adobriyan@...il.com
Subject: Re: [PATCH] kref: add function for reading kref value

Le lundi 12 décembre 2011 à 18:42 +0200, Daniel Baluta a écrit :

> Yes, but you have to do this each time you start debugging, for a
> particular referenced counted object.
> 

What a big deal.

> We must find a clever solution to avoid the noise. (e.g use
> /proc, /sysfs, /debugfs options to trigger dumping info for
> some/all objects with a certain state).
> 
> Usecase:
> 
> At some point we need to know all objects with refcount X,
> and their history of get/put operations.
> 
> For us it would have been very useful when debugging dev
> refcnts problems. With the current implementation kernel
> only dumped info at dev.c:5429:
> 

current on your git repo maybe, not on ours :(

> printk(KERN_EMERG "unregister_netdevice: "
>        waiting for %s to become free. Usage "
>        count = %d\n",
>        dev->name, atomic_read(&dev->refcnt));
> 

This is a very good example where you _cannot_ use kref, since we now
use a percpu refcnt fot netdevice.



--
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