[patch] cciss: Fix problem that deleting multiple logical drives could cause a panic

[patch] cciss: Fix problem that deleting multiple logical drives could cause a panic

[scameron]

Fix problem that deleting multiple logical drives could cause a panic.

Signed-off-by: Stephen M. Cameron <scameron@beardog.cca.cpqcorp.net>
---

 drivers/block/cciss.c |    5 +++++
 1 file changed, 5 insertions(+)

diff -puN drivers/block/cciss.c~fix_rebuild_lun_table_bug drivers/block/cciss.c
--- linux-2.6.28-rc8/drivers/block/cciss.c~fix_rebuild_lun_table_bug	2008-12-16 14:00:52.000000000 -0600
+++ linux-2.6.28-rc8-root/drivers/block/cciss.c	2008-12-16 14:00:52.000000000 -0600
@@ -1693,6 +1693,11 @@ static int rebuild_lun_table(ctlr_info_t
 	for (i = 0; i <= h->highest_lun; i++) {
 		int j;
 		drv_found = 0;
+
+		/* skip holes in the array from already deleted drives */
+		if (h->drv[i].raid_level == -1)
+			continue;
+
 		for (j = 0; j < num_luns; j++) {
 			memcpy(&lunid, &ld_buff->LUN[j][0], 4);
 			lunid = le32_to_cpu(lunid);
_

Re: [patch] cciss: Fix problem that deleting multiple logical drives could cause a panic

[Jens Axboe]

On Tue, Dec 16 2008, scameron@beardog.cca.cpqcorp.net wrote:
> 
> Fix problem that deleting multiple logical drives could cause a panic.

This looks like a 2.6.28 candidate, correct?

> 
> Signed-off-by: Stephen M. Cameron <scameron@beardog.cca.cpqcorp.net>
> ---
> 
>  drivers/block/cciss.c |    5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff -puN drivers/block/cciss.c~fix_rebuild_lun_table_bug drivers/block/cciss.c
> --- linux-2.6.28-rc8/drivers/block/cciss.c~fix_rebuild_lun_table_bug	2008-12-16 14:00:52.000000000 -0600
> +++ linux-2.6.28-rc8-root/drivers/block/cciss.c	2008-12-16 14:00:52.000000000 -0600
> @@ -1693,6 +1693,11 @@ static int rebuild_lun_table(ctlr_info_t
>  	for (i = 0; i <= h->highest_lun; i++) {
>  		int j;
>  		drv_found = 0;
> +
> +		/* skip holes in the array from already deleted drives */
> +		if (h->drv[i].raid_level == -1)
> +			continue;
> +
>  		for (j = 0; j < num_luns; j++) {
>  			memcpy(&lunid, &ld_buff->LUN[j][0], 4);
>  			lunid = le32_to_cpu(lunid);
> _

-- 
Jens Axboe

Re: [patch] cciss: Fix problem that deleting multiple logical drives could cause a panic

[scameron]

On Tue, Dec 16, 2008 at 09:27:30PM +0100, Jens Axboe wrote:
> On Tue, Dec 16 2008, scameron@beardog.cca.cpqcorp.net wrote:
> > 
> > Fix problem that deleting multiple logical drives could cause a panic.
> 
> This looks like a 2.6.28 candidate, correct?

Yes, and we would like to get it in anywhere else it needs to go
(backport to 2.6.27.x? if that makes sense.)

It fixes a panic which can be easily reproduced in the following
way: Just create several "arrays," each with multiple logical 
drives via hpacucli, then delete the first array, and it will blow
up in deregister_disk(), in the call to get_host() when it tries to
dig the hba pointer out of a NULL queue pointer.

The problem has been present since my code to make 
rebuild_lun_table behave better went in.

-- steve

> 
> > 
> > Signed-off-by: Stephen M. Cameron <scameron@beardog.cca.cpqcorp.net>
> > ---
> > 
> >  drivers/block/cciss.c |    5 +++++
> >  1 file changed, 5 insertions(+)
> > 
> > diff -puN drivers/block/cciss.c~fix_rebuild_lun_table_bug drivers/block/cciss.c
> > --- linux-2.6.28-rc8/drivers/block/cciss.c~fix_rebuild_lun_table_bug	2008-12-16 14:00:52.000000000 -0600
> > +++ linux-2.6.28-rc8-root/drivers/block/cciss.c	2008-12-16 14:00:52.000000000 -0600
> > @@ -1693,6 +1693,11 @@ static int rebuild_lun_table(ctlr_info_t
> >  	for (i = 0; i <= h->highest_lun; i++) {
> >  		int j;
> >  		drv_found = 0;
> > +
> > +		/* skip holes in the array from already deleted drives */
> > +		if (h->drv[i].raid_level == -1)
> > +			continue;
> > +
> >  		for (j = 0; j < num_luns; j++) {
> >  			memcpy(&lunid, &ld_buff->LUN[j][0], 4);
> >  			lunid = le32_to_cpu(lunid);
> > _
> 
> -- 
> Jens Axboe
> 

Re: [patch] cciss: Fix problem that deleting multiple logical drives could cause a panic

[Jens Axboe]

On Tue, Dec 16 2008, scameron@beardog.cca.cpqcorp.net wrote:
> On Tue, Dec 16, 2008 at 09:27:30PM +0100, Jens Axboe wrote:
> > On Tue, Dec 16 2008, scameron@beardog.cca.cpqcorp.net wrote:
> > > 
> > > Fix problem that deleting multiple logical drives could cause a panic.
> > 
> > This looks like a 2.6.28 candidate, correct?
> 
> Yes, and we would like to get it in anywhere else it needs to go
> (backport to 2.6.27.x? if that makes sense.)
> 
> It fixes a panic which can be easily reproduced in the following
> way: Just create several "arrays," each with multiple logical 
> drives via hpacucli, then delete the first array, and it will blow
> up in deregister_disk(), in the call to get_host() when it tries to
> dig the hba pointer out of a NULL queue pointer.
> 
> The problem has been present since my code to make 
> rebuild_lun_table behave better went in.

OK, I'll make sure it goes upstream for 2.6.28. I've merged your other
cciss patch for 2.6.29.

-- 
Jens Axboe