From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- fs/tracefs/internal.h | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) create mode 100644 fs/tracefs/internal.h (limited to 'fs/tracefs/internal.h') diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h new file mode 100644 index 000000000..c61481d04 --- /dev/null +++ b/fs/tracefs/internal.h @@ -0,0 +1,82 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _TRACEFS_INTERNAL_H +#define _TRACEFS_INTERNAL_H + +enum { + TRACEFS_EVENT_INODE = BIT(1), + TRACEFS_GID_PERM_SET = BIT(2), + TRACEFS_UID_PERM_SET = BIT(3), + TRACEFS_INSTANCE_INODE = BIT(4), +}; + +struct tracefs_inode { + struct inode vfs_inode; + /* The below gets initialized with memset_after(ti, 0, vfs_inode) */ + struct list_head list; + unsigned long flags; + void *private; +}; + +/* + * struct eventfs_attr - cache the mode and ownership of a eventfs entry + * @mode: saved mode plus flags of what is saved + * @uid: saved uid if changed + * @gid: saved gid if changed + */ +struct eventfs_attr { + int mode; + kuid_t uid; + kgid_t gid; +}; + +/* + * struct eventfs_inode - hold the properties of the eventfs directories. + * @list: link list into the parent directory + * @rcu: Union with @list for freeing + * @children: link list into the child eventfs_inode + * @entries: the array of entries representing the files in the directory + * @name: the name of the directory to create + * @entry_attrs: Saved mode and ownership of the @d_children + * @data: The private data to pass to the callbacks + * @attr: Saved mode and ownership of eventfs_inode itself + * @is_freed: Flag set if the eventfs is on its way to be freed + * Note if is_freed is set, then dentry is corrupted. + * @is_events: Flag set for only the top level "events" directory + * @nr_entries: The number of items in @entries + * @ino: The saved inode number + */ +struct eventfs_inode { + struct list_head list; + union { + struct list_head children; + struct rcu_head rcu; + }; + const struct eventfs_entry *entries; + const char *name; + struct eventfs_attr *entry_attrs; + void *data; + struct eventfs_attr attr; + struct kref kref; + unsigned int is_freed:1; + unsigned int is_events:1; + unsigned int nr_entries:30; + unsigned int ino; +}; + +static inline struct tracefs_inode *get_tracefs(const struct inode *inode) +{ + return container_of(inode, struct tracefs_inode, vfs_inode); +} + +struct dentry *tracefs_start_creating(const char *name, struct dentry *parent); +struct dentry *tracefs_end_creating(struct dentry *dentry); +struct dentry *tracefs_failed_creating(struct dentry *dentry); +struct inode *tracefs_get_inode(struct super_block *sb); + +void eventfs_remount(struct tracefs_inode *ti, bool update_uid, bool update_gid); +void eventfs_d_release(struct dentry *dentry); + +int eventfs_remount_lock(void); +void eventfs_remount_unlock(int srcu_idx); + +#endif /* _TRACEFS_INTERNAL_H */ -- cgit v1.3.1