Bug#801925: [PATCH] SCSI: fix crashes in sd and sr runtime PM
Hello Alan,
Thank you:
The patch appears to work for me, too.
Applied on top of Debian kernel "4.4-1~exp1" I finally have a kernel boot again!
(And maybe this will also make the Intel ( i7-2677M IGP) video bugs
disappear...)
Best regards,
Erich
On Wed, Jan 20, 2016 at 5:26 PM, Alan Stern <stern@rowland.harvard.edu> wrote:
> Runtime suspend during driver probe and removal can cause problems.
> The driver's runtime_suspend or runtime_resume callbacks may invoked
> before the driver has finished binding to the device or after the
> driver has unbound from the device.
>
> This problem shows up with the sd and sr drivers, and can cause disk
> or CD/DVD drives to become unusable as a result. The fix is simple.
> The drivers store a pointer to the scsi_disk or scsi_cd structure as
> their private device data when probing is finished, so we simply have
> to be sure to clear the private data during removal and test it during
> runtime suspend/resume.
>
> This fixes <https://bugs.debian.org/801925>.
>
> Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
> Reported-by: Paul Menzel <paul.menzel@giantmonkey.de>
> Reported-by: Erich Schubert <erich@debian.org>
> Reported-by: Alexandre Rossi <alexandre.rossi@gmail.com>
> Tested-by: Paul Menzel <paul.menzel@giantmonkey.de>
> CC: "James E.J. Bottomley" <JBottomley@odin.com>
> CC: Ben Hutchings <ben@decadent.org.uk>
> CC: <stable@vger.kernel.org>
>
> ---
>
>
> [as1795]
>
>
> drivers/scsi/sd.c | 7 +++++--
> drivers/scsi/sr.c | 4 ++++
> 2 files changed, 9 insertions(+), 2 deletions(-)
>
> Index: usb-4.4/drivers/scsi/sd.c
> ===================================================================
> --- usb-4.4.orig/drivers/scsi/sd.c
> +++ usb-4.4/drivers/scsi/sd.c
> @@ -3275,8 +3275,8 @@ static int sd_suspend_common(struct devi
> struct scsi_disk *sdkp = dev_get_drvdata(dev);
> int ret = 0;
>
> - if (!sdkp)
> - return 0; /* this can happen */
> + if (!sdkp) /* E.g.: runtime suspend following sd_remove() */
> + return 0;
>
> if (sdkp->WCE && sdkp->media_present) {
> sd_printk(KERN_NOTICE, sdkp, "Synchronizing SCSI cache\n");
> @@ -3315,6 +3315,9 @@ static int sd_resume(struct device *dev)
> {
> struct scsi_disk *sdkp = dev_get_drvdata(dev);
>
> + if (!sdkp) /* E.g.: runtime resume at the start of sd_probe() */
> + return 0;
> +
> if (!sdkp->device->manage_start_stop)
> return 0;
>
> Index: usb-4.4/drivers/scsi/sr.c
> ===================================================================
> --- usb-4.4.orig/drivers/scsi/sr.c
> +++ usb-4.4/drivers/scsi/sr.c
> @@ -144,6 +144,9 @@ static int sr_runtime_suspend(struct dev
> {
> struct scsi_cd *cd = dev_get_drvdata(dev);
>
> + if (!cd) /* E.g.: runtime suspend following sr_remove() */
> + return 0;
> +
> if (cd->media_present)
> return -EBUSY;
> else
> @@ -985,6 +988,7 @@ static int sr_remove(struct device *dev)
> scsi_autopm_get_device(cd->device);
>
> del_gendisk(cd->disk);
> + dev_set_drvdata(dev, NULL);
>
> mutex_lock(&sr_ref_mutex);
> kref_put(&cd->kref, sr_kref_release);
>
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