lkml.org 
[lkml]   [2017]   [May]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
Subject[block-xen-blkback] question about pontential null pointer dereference

Hello everybody,

While looking into Coverity ID 1350942 I ran into the following piece
of code at drivers/block/xen-blkback/xenbus.c:490:

490static int xen_blkbk_remove(struct xenbus_device *dev)
491{
492 struct backend_info *be = dev_get_drvdata(&dev->dev);
493
494 pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
495
496 if (be->major || be->minor)
497 xenvbd_sysfs_delif(dev);
498
499 if (be->backend_watch.node) {
500 unregister_xenbus_watch(&be->backend_watch);
501 kfree(be->backend_watch.node);
502 be->backend_watch.node = NULL;
503 }
504
505 dev_set_drvdata(&dev->dev, NULL);
506
507 if (be->blkif)
508 xen_blkif_disconnect(be->blkif);
509
510 /* Put the reference we set in xen_blkif_alloc(). */
511 xen_blkif_put(be->blkif);
512 kfree(be->mode);
513 kfree(be);
514 return 0;
515}

The issue here is that line 507 implies that be->blkif might be NULL.
If this is the case, there is a NULL pointer dereference when
executing line 511 once macro xen_blkif_put() dereference be->blkif

Is there any chance for be->blkif to be NULL at line 511?

I'm trying to figure out if this is a false positive or something that
actually needs to be fixed.

I'd really appreciate any comment on this.

Thank you!
--
Gustavo A. R. Silva




\
 
 \ /
  Last update: 2017-05-10 21:22    [W:0.047 / U:35.192 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site