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authorAlan Stern <stern@rowland.harvard.edu>2015-08-17 11:02:42 -0400
committerJames Bottomley <JBottomley@Odin.com>2015-08-18 08:14:14 -0700
commit49718f0fb8c9af192b33d8af3a2826db04025371 (patch)
parentdb196935d9562abec4510f48d887bc1f1e054fcf (diff)
SCSI: Fix NULL pointer dereference in runtime PM
The routines in scsi_rpm.c assume that if a runtime-PM callback is invoked for a SCSI device, it can only mean that the device's driver has asked the block layer to handle the runtime power management (by calling blk_pm_runtime_init(), which among other things sets q->dev). However, this assumption turns out to be wrong for things like the ses driver. Normally ses devices are not allowed to do runtime PM, but userspace can override this setting. If this happens, the kernel gets a NULL pointer dereference when blk_post_runtime_resume() tries to use the uninitialized q->dev pointer. This patch fixes the problem by calling the block layer's runtime-PM routines only if the device's driver really does have a runtime-PM callback routine. Since ses doesn't define any such callbacks, the crash won't occur. This fixes Bugzilla #101371. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-by: Stanisław Pitucha <viraptor@gmail.com> Reported-by: Ilan Cohen <ilanco@gmail.com> Tested-by: Ilan Cohen <ilanco@gmail.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Cc: stable@vger.kernel.org Signed-off-by: James Bottomley <JBottomley@Odin.com>
1 files changed, 11 insertions, 11 deletions
diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c
index 9e43ae1d2163..e4b799837948 100644
--- a/drivers/scsi/scsi_pm.c
+++ b/drivers/scsi/scsi_pm.c
@@ -217,15 +217,15 @@ static int sdev_runtime_suspend(struct device *dev)
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
struct scsi_device *sdev = to_scsi_device(dev);
- int err;
+ int err = 0;
- err = blk_pre_runtime_suspend(sdev->request_queue);
- if (err)
- return err;
- if (pm && pm->runtime_suspend)
+ if (pm && pm->runtime_suspend) {
+ err = blk_pre_runtime_suspend(sdev->request_queue);
+ if (err)
+ return err;
err = pm->runtime_suspend(dev);
- blk_post_runtime_suspend(sdev->request_queue, err);
+ blk_post_runtime_suspend(sdev->request_queue, err);
+ }
return err;
@@ -248,11 +248,11 @@ static int sdev_runtime_resume(struct device *dev)
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
int err = 0;
- blk_pre_runtime_resume(sdev->request_queue);
- if (pm && pm->runtime_resume)
+ if (pm && pm->runtime_resume) {
+ blk_pre_runtime_resume(sdev->request_queue);
err = pm->runtime_resume(dev);
- blk_post_runtime_resume(sdev->request_queue, err);
+ blk_post_runtime_resume(sdev->request_queue, err);
+ }
return err;