linux-kernel - [PATCH] vdpa: Fix IDR memory leak in VDUSE module exit

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Message-ID: <20250704125335.1084649-1-anders.roxell@linaro.org>
Date: Fri,  4 Jul 2025 14:53:35 +0200
From: Anders Roxell <anders.roxell@...aro.org>
To: mst@...hat.com,
	jasowang@...hat.com
Cc: virtualization@...ts.linux.dev,
	linux-kernel@...r.kernel.org,
	arnd@...db.de,
	Anders Roxell <anders.roxell@...aro.org>
Subject: [PATCH] vdpa: Fix IDR memory leak in VDUSE module exit

Add missing idr_destroy() call in vduse_exit() to properly free the
vduse_idr radix tree nodes. Without this, module load/unload cycles leak
576-byte radix tree node allocations, detectable by kmemleak as:

unreferenced object (size 576):
  backtrace:
    [<ffffffff81234567>] radix_tree_node_alloc+0xa0/0xf0
    [<ffffffff81234568>] idr_get_free+0x128/0x280

The vduse_idr is initialized via DEFINE_IDR() at line 136 and used throughout
the VDUSE (vDPA Device in Userspace) driver for device ID management. The fix
follows the documented pattern in lib/idr.c and matches the cleanup approach
used by other drivers.

This leak was discovered through comprehensive module testing with cumulative
kmemleak detection across 10 load/unload iterations per module.

Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace")
Signed-off-by: Anders Roxell <anders.roxell@...aro.org>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 6a9a37351310..04620bb77203 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -2216,6 +2216,7 @@ static void vduse_exit(void)
 	cdev_del(&vduse_ctrl_cdev);
 	unregister_chrdev_region(vduse_major, VDUSE_DEV_MAX);
 	class_unregister(&vduse_class);
+	idr_destroy(&vduse_idr);
 }
 module_exit(vduse_exit);

-- 
2.47.2