Date: Mon, 24 Nov 2003 15:19:52 -0800 From: Richard Bass <rbass@netraverse.com> To: aic7xxx@freebsd.org Subject: Re: Deadlock on linux 2.6.0-test10 Message-ID: <3FC29218.5050406@netraverse.com> In-Reply-To: <3FC28F53.1060407@netraverse.com> References: <3FC28F53.1060407@netraverse.com>
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Sigh. Well... it turns out that someone has already fixed this:
http://linux-scsi.bkbits.net:8080/scsi-bugfixes-2.6/ChangeSet@-1d?nav=index.html
Sorry for the extra noise.
Richard <rwb>
--
Richard W. Bass
Systems Software Architect
NeTraverse, Inc.
Richard Bass wrote:
> I am not sure whether this is the right mailing list to report this to,
> but please excuse me if not.
>
> There was a deadlock introduced in going from linux-2.6.0-test9 to
> linux-2.6.0-test10
> The hardware info is as follows (when printed out by the test9 kernel):
> -------------------------
> scsi0 : Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev 6.2.35
> <Adaptec 19160B Ultra160 SCSI adapter>
> aic7892: Ultra160 Wide Channel A, SCSI Id=8, 32/253 SCBs
>
> (scsi0:A:1): 160.000MB/s transfers (80.000MHz DT, offset 63, 16bit)
> (scsi0:A:4): 10.000MB/s transfers (10.000MHz, offset 16)
> Vendor: QUANTUM Model: ATLAS_V_18_WLS Rev: 0230
> Type: Direct-Access ANSI SCSI revision: 03
> scsi0:A:1:0: Tagged Queuing enabled. Depth 253
> Vendor: TOSHIBA Model: CD-ROM XM-6401TA Rev: 1009
> Type: CD-ROM ANSI SCSI revision: 02
> SCSI device sda: 35861388 512-byte hdwr sectors (18361 MB)
> SCSI device sda: drive cache: write back
> sda: sda1 sda2
> --------------------------
>
> Now, the change that got made was in the generic Linux code, but
> after doing a little hunting around, it looks like maybe the problem
> is in the Adaptec driver. In any event, here is the traceback:
>
> ahc_linux_register_host
>
> ahc_lock(ahd, &s)
> spin_lock_irqsave(&ahc->platform_data->spin_lock, *flags);
> (obtains the spinlock)
>
> scsi_assign_lock(host, &ahc->platform_data->spin_lock);
> (assigns ahc->platform_data->spin_lock to shost->host_lock
>
> ahc_linux_initialize_scsi_bus
> ahc_reset_channel(ahc, 'A', /*initiate_reset*/TRUE);
> ahc_send_async
> scsi_report_device_reset
> shost_for_each_device(sdev, shost)
> __scsi_iterate_devices
> spin_lock_irqsave(shost->host_lock, flags);
> ^^^
> DEADLOCK
>
>
> The change was that shost_for_each_device() now uses
> __scsi_iterate_devices()
> which goes and gets the host_lock spinlock. It kind of looked like you
> shouldn't call ahc_send_async() with a lock, but I could be wrong here.
> The problem may be in the generic stuff. If so, I am sure the aic7xxx
> maintainer can better explain what is going wrong there.
>
> Hope this helps,
>
> Richard <rwb>
>
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