Bug#801925: NULL pointer dereference: IP: [<f828a00c>] sr_runtime_suspend+0xc/0x20 [sr_mod]
On Tue, 19 Jan 2016, Paul Menzel wrote:
> Could you please attach the debugging patch. Hopefully Alexandre, Erich,
> or I will have some spare time to build an image from it.
Actually, this patch is an attempt at a fix. After looking more
carefully at your log pictures, I realized what the problem must be.
It's too bad nobody was able to capture a log where the error
occurred in sr_runtime_suspend, though -- all the logs in the bug
report show sd_runtime_resume.
> Alan, thank you a lot for being so responsive and helpful!
You're welcome.
Alan Stern
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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