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From:   Nathan Chancellor <nathan@kernel.org>
Date:   Wed, 18 Oct 2023 11:10:31 -0700
Subject: [PATCH] eventfs: Use ERR_CAST() in eventfs_create_events_dir()
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Message-Id: <20231018-ftrace-fix-clang-randstruct-v1-1-338cb214abfb@kernel.org>
To:     rostedt@goodmis.org, mhiramat@kernel.org
Cc:     keescook@chromium.org, ndesaulniers@google.com, trix@redhat.com,
        linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
        llvm@lists.linux.dev, patches@lists.linux.dev,
        Nathan Chancellor <nathan@kernel.org>
Precedence: bulk

When building with clang and CONFIG_RANDSTRUCT_FULL=y, there is an error
due to a cast in eventfs_create_events_dir():

  fs/tracefs/event_inode.c:734:10: error: casting from randomized structure pointer type 'struct dentry *' to 'struct eventfs_inode *'
    734 |                 return (struct eventfs_inode *)dentry;
        |                        ^
  1 error generated.

Use the ERR_CAST() function to resolve the error, as it was designed for
this exact situation (casting an error pointer to another type).

Closes: https://github.com/ClangBuiltLinux/linux/issues/1947
Fixes: 5790b1fb3d67 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 fs/tracefs/event_inode.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 1ccd100bc565..9f19b6608954 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -731,7 +731,7 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
 		return NULL;
 
 	if (IS_ERR(dentry))
-		return (struct eventfs_inode *)dentry;
+		return ERR_CAST(dentry);
 
 	ei = kzalloc(sizeof(*ei), GFP_KERNEL);
 	if (!ei)

---
base-commit: 5ddd8baa4857709b4e5d84b376d735152851955b
change-id: 20231018-ftrace-fix-clang-randstruct-0cb6899523ac

Best regards,
-- 
Nathan Chancellor <nathan@kernel.org>