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authorJuergen Gross <jgross@suse.com>2021-04-23 07:40:38 +0200
committerJuergen Gross <jgross@suse.com>2021-05-10 09:32:00 +0200
commit970655aa9b42461f8394e4457307005bdeee14d9 (patch)
tree3181bb4b00415833f5f2d3c39548bbd3189910d2 /drivers/xen
parent6efb943b8616ec53a5e444193dccf1af9ad627b5 (diff)
downloadlinux-970655aa9b42461f8394e4457307005bdeee14d9.tar.gz
xen/gntdev: fix gntdev_mmap() error exit path
Commit d3eeb1d77c5d0af ("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: d3eeb1d77c5d0af ("xen/gntdev: use mmu_interval_notifier_insert")
Cc: stable@vger.kernel.org
Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>
Link: https://lore.kernel.org/r/20210423054038.26696-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/gntdev.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index f01d58c7a042..a3e7be96527d 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -1017,8 +1017,10 @@ 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);