linux-kernel - Re: mcs7830 usb net: "scheduling while atomic" danger?

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 for Android: free password hash cracker in your pocket

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

Date:	Mon, 18 Jan 2010 23:25:10 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	Julia Lawall <julia@...u.dk>
Cc:	Andreas Mohr <andi@...as.de>, linux-kernel@...r.kernel.org,
	Greg KH <greg@...ah.com>, Alek Du <alek.du@...el.com>,
	Jacob Pan <jacob.jun.pan@...el.com>,
	Alan Stern <stern@...land.harvard.edu>
Subject: Re: mcs7830 usb net: "scheduling while atomic" danger?

On Monday 18 January 2010, Julia Lawall wrote:
> > That code looks indeed broken as was added las July as part of 331ac6b288d9
> > "USB: EHCI: Add Intel Moorestown EHCI controller HOSTPCx extensions and
> > support phy low power mode". The reason that this hasn't triggered is
> > probably the lack of Moorestown machines in the field.
> 
> The fix is just msleep -> mdelay?

No, that would just kill the warning but still leave horrible code. There
should really be some way to move the sleeping operation outside of the
spinlock.

>From a brief look at the code, I think the sequence could be converted
from

lock();
suspend();
sleep();
clock_disable();
unlock();

to

lock();
again:
suspend();
unlock();
sleep();
lock();
if (!suspended())
   goto again;
clock_disable();
unlock();

	Arnd
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/