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 --- tools/perf/util/namespaces.h | 84 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 tools/perf/util/namespaces.h (limited to 'tools/perf/util/namespaces.h') diff --git a/tools/perf/util/namespaces.h b/tools/perf/util/namespaces.h new file mode 100644 index 000000000..e95c79b80 --- /dev/null +++ b/tools/perf/util/namespaces.h @@ -0,0 +1,84 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * + * Copyright (C) 2017 Hari Bathini, IBM Corporation + */ + +#ifndef __PERF_NAMESPACES_H +#define __PERF_NAMESPACES_H + +#include +#include +#include +#include +#include +#include +#include + +#ifndef HAVE_SETNS_SUPPORT +int setns(int fd, int nstype); +#endif + +struct perf_record_namespaces; + +struct namespaces { + struct list_head list; + u64 end_time; + struct perf_ns_link_info link_info[]; +}; + +struct namespaces *namespaces__new(struct perf_record_namespaces *event); +void namespaces__free(struct namespaces *namespaces); + +DECLARE_RC_STRUCT(nsinfo) { + pid_t pid; + pid_t tgid; + pid_t nstgid; + bool need_setns; + bool in_pidns; + char *mntns_path; + refcount_t refcnt; +}; + +struct nscookie { + int oldns; + int newns; + char *oldcwd; +}; + +int nsinfo__init(struct nsinfo *nsi); +struct nsinfo *nsinfo__new(pid_t pid); +struct nsinfo *nsinfo__copy(const struct nsinfo *nsi); + +struct nsinfo *nsinfo__get(struct nsinfo *nsi); +void nsinfo__put(struct nsinfo *nsi); + +bool nsinfo__need_setns(const struct nsinfo *nsi); +void nsinfo__clear_need_setns(struct nsinfo *nsi); +pid_t nsinfo__tgid(const struct nsinfo *nsi); +pid_t nsinfo__nstgid(const struct nsinfo *nsi); +pid_t nsinfo__pid(const struct nsinfo *nsi); +bool nsinfo__in_pidns(const struct nsinfo *nsi); +void nsinfo__set_in_pidns(struct nsinfo *nsi); + +void nsinfo__mountns_enter(struct nsinfo *nsi, struct nscookie *nc); +void nsinfo__mountns_exit(struct nscookie *nc); + +char *nsinfo__realpath(const char *path, struct nsinfo *nsi); +int nsinfo__stat(const char *filename, struct stat *st, struct nsinfo *nsi); + +bool nsinfo__is_in_root_namespace(void); + +static inline void __nsinfo__zput(struct nsinfo **nsip) +{ + if (nsip) { + nsinfo__put(*nsip); + *nsip = NULL; + } +} + +#define nsinfo__zput(nsi) __nsinfo__zput(&nsi) + +const char *perf_ns__name(unsigned int id); + +#endif /* __PERF_NAMESPACES_H */ -- cgit v1.3.1