SCSI: fix race in device_create

There is a race from when a device is created with device_create() and
then the drvdata is set with a call to dev_set_drvdata() in which a
sysfs file could be open, yet the drvdata will be NULL, causing all
sorts of bad things to happen.

This patch fixes the problem by using the new function,
device_create_drvdata().  It fixes the problem in all of the scsi
drivers that need it.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 7 insertions, 5 deletions

diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index e8db66ad0bde..6e5a5bb31311 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -4424,17 +4424,19 @@ static int do_create_class_files(struct scsi_tape *STp, int dev_num, int mode)
                 snprintf(name, 10, "%s%s%s", rew ? "n" : "",
                          STp->disk->disk_name, st_formats[i]);
                 st_class_member =
-                        device_create(st_sysfs_class, &STp->device->sdev_gendev,
-                                      MKDEV(SCSI_TAPE_MAJOR,
-                                                TAPE_MINOR(dev_num, mode, rew)),
-                                      "%s", name);
+                        device_create_drvdata(st_sysfs_class,
+                                              &STp->device->sdev_gendev,
+                                              MKDEV(SCSI_TAPE_MAJOR,
+                                                    TAPE_MINOR(dev_num,
+                                                              mode, rew)),
+                                              &STp->modes[mode],
+                                              "%s", name);
                 if (IS_ERR(st_class_member)) {
                         printk(KERN_WARNING "st%d: device_create failed\n",
                                dev_num);
                         error = PTR_ERR(st_class_member);
                         goto out;
                 }
-                dev_set_drvdata(st_class_member, &STp->modes[mode]);
 
                 error = device_create_file(st_class_member,
                                            &dev_attr_defined);