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* [PATCH] xen/gntdev: fix gntdev_mmap() error exit path
@ 2021-04-23  5:40 Juergen Gross
  2021-04-23  6:55 ` Luca Fancellu
  2021-05-10  9:26 ` Juergen Gross
  0 siblings, 2 replies; 6+ messages in thread
From: Juergen Gross @ 2021-04-23  5:40 UTC (permalink / raw)
  To: xen-devel, linux-kernel
  Cc: Juergen Gross, Boris Ostrovsky, Stefano Stabellini, stable,
	Marek Marczykowski-Górecki

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>
---
 drivers/xen/gntdev.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

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);
 
-- 
2.26.2



^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2021-05-10  9:26 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-23  5:40 [PATCH] xen/gntdev: fix gntdev_mmap() error exit path Juergen Gross
2021-04-23  6:55 ` Luca Fancellu
2021-04-23  7:00   ` Juergen Gross
2021-04-23  7:04     ` Luca Fancellu
2021-05-08  0:41       ` Marek Marczykowski-Górecki
2021-05-10  9:26 ` Juergen Gross

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