Commit 970655aa authored by Juergen Gross's avatar Juergen Gross
Browse files

xen/gntdev: fix gntdev_mmap() error exit path 



Commit d3eeb1d7 ("xen/gntdev: use mmu_interval_notifier_insert")
introduced an error in gntdev_mmap(): in case the call of
mmu_interval_notifier_insert_locked() fails the exit path should not
call mmu_interval_notifier_remove(), as this might result in NULL
dereferences.

One reason for failure is e.g. a signal pending for the running
process.

Fixes: d3eeb1d7 ("xen/gntdev: use mmu_interval_notifier_insert")
Cc: stable@vger.kernel.org
Reported-by: default avatarMarek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Tested-by: default avatarMarek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Reviewed-by: default avatarLuca Fancellu <luca.fancellu@arm.com>
Link: https://lore.kernel.org/r/20210423054038.26696-1-jgross@suse.com


Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent 6efb943b

drivers/xen/gntdev.c

+3 −1
Original line number Diff line number Diff line
@@ -1017,9 +1017,11 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) 
		err = mmu_interval_notifier_insert_locked(

			&map->notifier, vma->vm_mm, vma->vm_start,

			vma->vm_end - vma->vm_start, &gntdev_mmu_ops);

		if (err)

		if (err) {

			map->vma = NULL;

			goto out_unlock_put;

		}

	}

	mutex_unlock(&priv->lock);



	if (use_ptemod) {