linux-kernel - [PATCH v2] drm/lease: fix WARNING in idr

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Date:   Wed, 18 Mar 2020 15:53:50 +0800
From:   Qiujun Huang <hqjagain@...il.com>
To:     daniel@...ll.ch
Cc:     maarten.lankhorst@...ux.intel.com, mripard@...nel.org,
        airlied@...ux.ie, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, anenbupt@...il.com,
        Qiujun Huang <hqjagain@...il.com>
Subject: [PATCH v2] drm/lease: fix WARNING in idr_destroy

drm_lease_create takes ownership of leases. And leases will be released
by drm_master_put.

drm_master_put
    ->drm_master_destroy
            ->idr_destroy

So we needn't call idr_destroy again.

Reported-and-tested-by: syzbot+05835159fe322770fe3d@...kaller.appspotmail.com
Signed-off-by: Qiujun Huang <hqjagain@...il.com>
---
 drivers/gpu/drm/drm_lease.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_lease.c b/drivers/gpu/drm/drm_lease.c
index b481caf..825abe3 100644
--- a/drivers/gpu/drm/drm_lease.c
+++ b/drivers/gpu/drm/drm_lease.c
@@ -542,10 +542,12 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev,
 	}
 
 	DRM_DEBUG_LEASE("Creating lease\n");
+	/* lessee will take the ownership of leases */
 	lessee = drm_lease_create(lessor, &leases);
 
 	if (IS_ERR(lessee)) {
 		ret = PTR_ERR(lessee);
+		idr_destroy(&leases);
 		goto out_leases;
 	}
 
@@ -580,7 +582,6 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev,
 
 out_leases:
 	put_unused_fd(fd);
-	idr_destroy(&leases);
 
 	DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl failed: %d\n", ret);
 	return ret;
-- 
1.8.3.1