Re: [PATCH 1/1] cciss: bug fix to prevent cciss from loading inkdump crash kernel

From: Mike Miller (OS Dev)
Date: Fri May 03 2013 - 14:18:11 EST


On Fri, 2013-05-03 at 11:02 -0700, James Bottomley wrote:
> On Tue, 2013-04-23 at 12:25 -0500, Mike Miller wrote:
> > PATCH 1/1
> >
> > By default the cciss driver supports all "older" HP Smart Array controllers
> > and hpsa supports all controllers starting with the G6 family. There are
> > module parameters that allow a user to override those defaults and use hpsa
> > for any HP Smart Array controller.
> > If the user does override the default behavior and uses hpsa for older
> > controllers it is possible that cciss may try to load in a kdump crash
> > kernel. This may happen if cciss is loaded first from the kdump initrd
> > image. If cciss does load rather than hpsa and reset_devices is true we
> > immediately call cciss_hard_reset_controller. This will result in a kernel
> > panic and the core file cannot be created.
> > This patch prevents cciss from trying to load in this scenario.
> >
> > Tested with 3.9.0-rc7.
> >
> > From: Mike <mike.miller@xxxxxx>
> > Signed-off-by: Mike Miller <mike.miller@xxxxxx>
> >
> > ---
> > drivers/block/cciss.c | 10 ++++++++++
> > 1 files changed, 10 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
> > index 1c1b8e5..06c8dba 100644
> > --- a/drivers/block/cciss.c
> > +++ b/drivers/block/cciss.c
> > @@ -4960,6 +4960,16 @@ static int cciss_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
> > ctlr_info_t *h;
> > unsigned long flags;
> >
> > + /*
> > + * By default the cciss driver is used for all older HP Smart Array
> > + * controllers. There are module paramaters that allow a user to
> > + * override this behavior and instead use the hpsa SCSI driver. If
> > + * this is the case cciss may be loaded first from the kdump initrd
> > + * image and cause a kernel panic. So if reset_devices is true and
> > + * cciss_allow_hpsa is set just bail.
> > + */
> > + if ((reset_devices) && (cciss_allow_hpsa == 1))
> > + return -ENODEV;
> > rc = cciss_init_reset_devices(pdev);
> > if (rc) {
> > if (rc != -ENOTSUPP)
>
> Sigh, right change log, incomplete bug fix.
>
> Can we all agree that this is the right one?
>
> James

I submitted 2 patches. Below the 2 are combined and make the fix
complete.

-- mikem

>
> ---
> >From 746ba9f715b9037264ae0b8175c6286f5f8f62d4 Mon Sep 17 00:00:00 2001
> From: Mike Miller <mike.miller@xxxxxx>
> Date: Thu, 18 Apr 2013 13:49:37 -0500
> Subject: [PATCH] [SCSI] cciss: bug fix to prevent cciss from loading in kdump
> crash kernel
>
> By default the cciss driver supports all "older" HP Smart Array controllers
> and hpsa supports all controllers starting with the G6 family. There are
> module parameters that allow a user to override those defaults and use hpsa
> for any HP Smart Array controller.
> If the user does override the default behavior and uses hpsa for older
> controllers it is possible that cciss may try to load in a kdump crash
> kernel. This may happen if cciss is loaded first from the kdump initrd
> image. If cciss does load rather than hpsa and reset_devices is true we
> immediately call cciss_hard_reset_controller. This will result in a kernel
> panic and the core file cannot be created.
> This patch prevents cciss from trying to load in this scenario.
>
> Signed-off-by: Mike Miller <mike.miller@xxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: James Bottomley <JBottomley@xxxxxxxxxxxxx>
>
> diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
> index 1c1b8e5..daaab88 100644
> --- a/drivers/block/cciss.c
> +++ b/drivers/block/cciss.c
> @@ -75,6 +75,12 @@ module_param(cciss_simple_mode, int, S_IRUGO|S_IWUSR);
> MODULE_PARM_DESC(cciss_simple_mode,
> "Use 'simple mode' rather than 'performant mode'");
>
> +static int cciss_allow_hpsa;
> +module_param(cciss_allow_hpsa, int, S_IRUGO|S_IWUSR);
> +MODULE_PARM_DESC(cciss_allow_hpsa,
> + "Prevent cciss driver from accessing hardware known to be "
> + " supported by the hpsa driver");
> +
> static DEFINE_MUTEX(cciss_mutex);
> static struct proc_dir_entry *proc_cciss;
>
> @@ -4960,6 +4966,16 @@ static int cciss_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
> ctlr_info_t *h;
> unsigned long flags;
>
> + /*
> + * By default the cciss driver is used for all older HP Smart Array
> + * controllers. There are module paramaters that allow a user to
> + * override this behavior and instead use the hpsa SCSI driver. If
> + * this is the case cciss may be loaded first from the kdump initrd
> + * image and cause a kernel panic. So if reset_devices is true and
> + * cciss_allow_hpsa is set just bail.
> + */
> + if ((reset_devices) && (cciss_allow_hpsa == 1))
> + return -ENODEV;
> rc = cciss_init_reset_devices(pdev);
> if (rc) {
> if (rc != -ENOTSUPP)
>
>


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