linux-kernel - [PATCH 5.10 279/452] misc: ocxl: fix possible double free in ocxl_file_register

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Date:   Tue,  7 Jun 2022 19:02:16 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Hangyu Hua <hbh25y@...il.com>,
        Frederic Barrat <fbarrat@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.10 279/452] misc: ocxl: fix possible double free in ocxl_file_register_afu

From: Hangyu Hua <hbh25y@...il.com>

[ Upstream commit 950cf957fe34d40d63dfa3bf3968210430b6491e ]

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>
Acked-by: Frederic Barrat <fbarrat@...ux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Link: https://lore.kernel.org/r/20220418085758.38145-1-hbh25y@gmail.com
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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 4d1b44de1492..c742ab02ae18 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -558,7 +558,9 @@ 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);
-- 
2.35.1