linux-kernel - Re: Possibly SATA related freeze killed networking and RAID

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: <47505A63.8070507@cfl.rr.com>
Date:	Fri, 30 Nov 2007 13:45:55 -0500
From:	Phillip Susi <psusi@....rr.com>
To:	Tejun Heo <htejun@...il.com>
CC:	Pavel Machek <pavel@....cz>, Alan Cox <alan@...rguk.ukuu.org.uk>,
	noah <noah123@...il.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	linux-ide@...r.kernel.org
Subject: Re: Possibly SATA related freeze killed networking and RAID

Tejun Heo wrote:
> Because SFF ATA controller don't have IRQ pending bit.  You don't know
> whether IRQ is raised or not.  Plus, accessing the status register which
> clears pending IRQ can be very slow on PATA machines.  It has to go
> through the PCI and ATA bus and come back.  So, unconditionally trying
> to clear IRQ by accessing Status can incur noticeable overhead if the
> IRQ is shared with devices which raise a lot of IRQs.

There HAS to be a way to determine if that device generated the 
interrupt, or the interrupt can not be shared.  Since the kernel said 
nobody cared about the interrupt, that indicates that the sata driver 
checked the status register and realized the sata chip didn't generate 
the interrupt, and returned to the kernel letting it know that the 
interrupt was not for it.

-
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/