From 8a7027f011c5127d2c6e756425a831445f763f0c Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Fri, 23 Apr 2021 07:40:38 +0200 Subject: [PATCH] xen/gntdev: fix gntdev_mmap() error exit path MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit 970655aa9b42461f8394e4457307005bdeee14d9 upstream. 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 Tested-by: Marek Marczykowski-Górecki Signed-off-by: Juergen Gross Reviewed-by: Luca Fancellu Link: https://lore.kernel.org/r/20210423054038.26696-1-jgross@suse.com Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman --- 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 5447c5156b2e..b9651f797676 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -1005,8 +1005,10 @@ 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); -- 2.34.1