misc: ocxl: fix possible double free in ocxl_file_register_afu

[ 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@gmail.com>
Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220418085758.38145-1-hbh25y@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index e70525eedaaeb1170eb19357af4671f799da4f48..d278f8ba2c7606384c7175d005db30b8cc713dd2 100644 (file)
--- 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);