netdev - Re: [PATCH] r8169: Fix irq masking in rtl8169

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]

Message-Id: <200903191158.52436.fzu@wemgehoertderstaat.de>
Date:	Thu, 19 Mar 2009 11:58:51 +0100
From:	Karsten Wiese <fzu@...gehoertderstaat.de>
To:	Francois Romieu <romieu@...zoreil.com>
Cc:	netdev@...r.kernel.org, Rafael Wysocki <rjw@...k.pl>
Subject: Re: [PATCH] r8169: Fix irq masking in rtl8169_interrupt()

Am Mittwoch 18 März 2009 schrieb Francois Romieu:
> Karsten Wiese <fzu@...gehoertderstaat.de> :
> > Am Mittwoch 18 März 2009 schrieb Francois Romieu:
> [...]
> > > If netif_rx_schedule fails after napi is enabled, there is a
> > > racing poll thread to care for the transfer.
> > > 
> > > Stated differently the bug is noticeable because napi_enable() 
> > > should be called before request_irq() in rtl8169_open, right ?
> > 
> > Propably yes. That would mean the first interrupt is received before
> > rtl_hw_start() is called in rtl8169_open. The source of that
> > interrupt would be something else then?
> 
> All we need is thus a shared interrupt racing on a different CPU
> with rtl8169_open and some IO versus memory reordering so that
> the hardware is started and a change in the status register can
> be seen in the IRQ handler before napi_enable/NAPI_STATE_SCHED
> escapes from the CPU where rtl8169_open is running...
> 
> It does not look like a credible explanation. :o/

Found it: CONFIG_DEBUG_SHIRQ is set here causing a "test-call" to
rtl8169_interrupt() from irq_request().

$SUBJECT patch is ok, me still thinks. You?

Thanks,
Karsten
--
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