diff mbox series

eventfs: Use ERR_CAST() in eventfs_create_events_dir()

Message ID 20231018-ftrace-fix-clang-randstruct-v1-1-338cb214abfb@kernel.org (mailing list archive)
State Accepted
Commit b8a555dc31e5aa18d976de0bc228006e398a2e7d
Headers show
Series eventfs: Use ERR_CAST() in eventfs_create_events_dir() | expand

Commit Message

Nathan Chancellor Oct. 18, 2023, 6:10 p.m. UTC 
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(-)


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

Best regards,

Comments

Kees Cook Oct. 18, 2023, 6:14 p.m. UTC | #1 
On Wed, Oct 18, 2023 at 11:10:31AM -0700, Nathan Chancellor wrote:
> 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>

Yes, please. That's the correct method to do such casts. Thanks!

Reviewed-by: Kees Cook <keescook@chromium.org>
diff mbox series

Patch

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)