linux-kernel - [PATCH] misc: ocxl: fix possible double free in ocxl_file_register

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Message-Id: <20220418085758.38145-1-hbh25y@gmail.com>
Date:   Mon, 18 Apr 2022 16:57:58 +0800
From:   Hangyu Hua <hbh25y@...il.com>
To:     fbarrat@...ux.ibm.com, ajd@...ux.ibm.com, arnd@...db.de,
        gregkh@...uxfoundation.org, mpe@...erman.id.au,
        alastair@...ilva.org
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        Hangyu Hua <hbh25y@...il.com>
Subject: [PATCH] misc: ocxl: fix possible double free in ocxl_file_register_afu

info_release() will be called in device_unregister() when info->dev's
reference count is 0. So there is no need to call ocxl_afu_put() and
kfree() again.

Fix this by adding free_minor() and return to err_unregister error path.

Fixes: 75ca758adbaf ("ocxl: Create a clear delineation between ocxl backend & frontend")
Signed-off-by: Hangyu Hua <hbh25y@...il.com>
---
 drivers/misc/ocxl/file.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index d881f5e40ad9..6777c419a8da 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -556,7 +556,9 @@ int ocxl_file_register_afu(struct ocxl_afu *afu)
 
 err_unregister:
 	ocxl_sysfs_unregister_afu(info); // safe to call even if register failed
+	free_minor(info);
 	device_unregister(&info->dev);
+	return rc;
 err_put:
 	ocxl_afu_put(afu);
 	free_minor(info);
-- 
2.25.1