[7059] in linux-scsi channel archive
[PATCH] Bug wrt failing init of scsi modules
daemon@ATHENA.MIT.EDU (Kurt Garloff)
Thu Aug 26 21:16:25 1999
Date: Fri, 27 Aug 1999 03:03:22 +0200
From: Kurt Garloff <garloff@suse.de>
To: Linus Torvalds <torvalds@transmeta.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Linux SCSI list <linux-scsi@vger.rutgers.edu>,
Linux kernel list <linux-kernel@vger.rutgers.edu>,
kernel@suse.de
Mail-Followup-To: Linus Torvalds <torvalds@transmeta.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Linux SCSI list <linux-scsi@vger.rutgers.edu>,
Linux kernel list <linux-kernel@vger.rutgers.edu>, kernel@suse.de
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Hi Linus, hi Alan,
attached is a bugfix for the following situation:
scsi_register_device_module() gets called and registers the device (sd, sr)
right at the beginning.
If this functions fails a little bit later in the ->init() function, then
the device does not get removed from the list of devices pointed to by
scsi_devicelist. [The (out_of_space) case is handled correctly, BTW.]
This leaves us with the device getting removed, as module init fails.
However the pointer scsi_devicelist points to the removed device resulting
in kernel Oopses on further SCSI operations.
Aug 26 23:45:57 kurt kernel: Unable to handle kernel paging request at=20
virtual address c8c1cb30
Aug 26 23:45:57 kurt kernel: EIP: 0010:[scan_scsis_single+1402/2064]
Aug 26 23:45:57 kurt kernel: esi: c8c1cb18 edi: c5091df4 ...
=20
You can loose the ability to access your harddisks by inserting sd_mod in a
kernel with sd compiled in because of this bug.
=20
Attached is a patch to fix it.
Patch is against 2.2.12, but 2.3.15 and 2.0.38 should be affected as well.
=20
--=20
Kurt Garloff <garloff@suse.de> Wuppertal, FRG
PGP2 key: See mail header, key servers Linux kernel development
SuSE GmbH, N=FCrnberg, FRG SCSI drivers: tmscsim(DC390), DC395
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Content-Description: 22x-scsi-mod-unregister.diff
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--- linux-2.2.12/drivers/scsi/scsi.c.orig Mon Aug 9 21:04:40 1999
+++ linux-2.2.12/drivers/scsi/scsi.c Fri Aug 27 02:53:47 1999
@@ -3110,6 +3110,7 @@
Scsi_Device * SDpnt;
struct Scsi_Host * shpnt;
int out_of_space =3D 0;
+ int no_detect =3D 0;
=20
if (tpnt->next) return 1;
=20
@@ -3123,7 +3124,7 @@
for(SDpnt =3D shpnt->host_queue; SDpnt;=20
SDpnt =3D SDpnt->next)
{
- if(tpnt->detect) SDpnt->attached +=3D (*tpnt->detect)(SDpnt);
+ if(tpnt->detect) SDpnt->attached +=3D (no_detect =3D (*tpnt->d=
etect)(SDpnt));
}
}
=20
@@ -3132,7 +3133,15 @@
* init function.
*/
if(tpnt->init && tpnt->dev_noticed)
- if ((*tpnt->init)()) return 1;
+ if ((*tpnt->init)())=20
+ {
+ /* We don't need full unregister and use our knowledge about
+ * the structure of scsi_devicelist instead. KG, 99/08/27 */
+ /* scsi_unregister_device (tpnt); */
+ SDpnt->attached -=3D no_detect;
+ scsi_devicelist =3D scsi_devicelist->next;
+ return 1;
+ }
=20
/*
* Now actually connect the devices to the new driver.
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