On Mon, 2013-04-08 at 13:42 +0200, Oskar Andero wrote:
> On 14:36 Thu 07 Mar , oskar.andero@xxxxxxxxxxxxxx wrote:
> > From: "syunsuke.x.itou" <syunsuke.x.itou@xxxxxxxxxxxxxx>
> >
> > By repeatadly connecting/disconnecting a USB masstorage device
> > a null pointer dereference can be provoked. This is caused by
> > sd_revalidate_disk() assuming sdkp to be a valid pointer. This
> > patch adds a null pointer check.
> >
> > Reviewed-by: Radovan Lekanovic <radovan.lekanovic@xxxxxxxxxxxxxx>
> > Signed-off-by: syunsuke.x.itou <syunsuke.x.itou@xxxxxxxxxxxxxx>
> > Signed-off-by: Oskar Andero <oskar.andero@xxxxxxxxxxxxxx>
> > ---
> > drivers/scsi/sd.c | 7 ++++++-
> > 1 files changed, 6 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> > index 7992635..49849ce 100644
> > --- a/drivers/scsi/sd.c
> > +++ b/drivers/scsi/sd.c
> > @@ -1,6 +1,7 @@
> > /*
> > * sd.c Copyright (C) 1992 Drew Eckhardt
> > * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
> > + * Copyright (C) 2013 Sony Mobile Communications AB.
> > *
> > * Linux scsi disk driver
> > * Initial versions: Drew Eckhardt
> > @@ -2653,10 +2654,14 @@ static int sd_try_extended_inquiry(struct scsi_device *sdp)
> > static int sd_revalidate_disk(struct gendisk *disk)
> > {
> > struct scsi_disk *sdkp = scsi_disk(disk);
> > - struct scsi_device *sdp = sdkp->device;
> > + struct scsi_device *sdp;
> > unsigned char *buffer;
> > unsigned flush = 0;
> >
> > + if (!sdkp)
> > + return -ENODEV;
> > + sdp = sdkp->device;
> > +
> > SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp,
> > "sd_revalidate_disk\n"));
> >
> > --
> > 1.7.8.6
> >
>
> Ping. Any input on the patch above?
For us to give input, the original patch would have to have been sent to
linux-scsi ...
However, I think it's not correct because it fixes a symptom, not the
cause. If sdkp can be null, that means something failed to get the
reference that's required. What's the stack trace?
James
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