From 0bb080ba6469a573bc85122153d931334d10a173 Mon Sep 17 00:00:00 2001 From: Alexandre Chartre Date: Fri, 21 Nov 2025 10:53:17 +0100 Subject: [PATCH] objtool: Disassemble instruction on warning or backtrace When an instruction warning (WARN_INSN) or backtrace (BT_INSN) is issued, disassemble the instruction to provide more context. Signed-off-by: Alexandre Chartre Signed-off-by: Peter Zijlstra (Intel) Acked-by: Josh Poimboeuf Link: https://patch.msgid.link/20251121095340.464045-8-alexandre.chartre@oracle.com --- tools/objtool/check.c | 36 ++++++++++++++++++++++----- tools/objtool/disas.c | 5 ++-- tools/objtool/include/objtool/check.h | 2 ++ tools/objtool/include/objtool/disas.h | 13 ++++++++++ tools/objtool/include/objtool/warn.h | 16 ++++++++---- 5 files changed, 58 insertions(+), 14 deletions(-) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 0999717abc9cb..4da1f07b35383 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -4792,11 +4792,34 @@ static void free_insns(struct objtool_file *file) free(chunk->addr); } +static struct disas_context *objtool_disas_ctx; + +const char *objtool_disas_insn(struct instruction *insn) +{ + struct disas_context *dctx = objtool_disas_ctx; + + if (!dctx) + return ""; + + disas_insn(dctx, insn); + return disas_result(dctx); +} + int check(struct objtool_file *file) { - struct disas_context *disas_ctx; + struct disas_context *disas_ctx = NULL; int ret = 0, warnings = 0; + /* + * If the verbose or backtrace option is used then we need a + * disassembly context to disassemble instruction or function + * on warning or backtrace. + */ + if (opts.verbose || opts.backtrace) { + disas_ctx = disas_context_create(file); + objtool_disas_ctx = disas_ctx; + } + arch_initial_func_cfi_state(&initial_func_cfi); init_cfi_state(&init_cfi); init_cfi_state(&func_cfi); @@ -4936,11 +4959,12 @@ out: if (opts.verbose) { if (opts.werror && warnings) WARN("%d warning(s) upgraded to errors", warnings); - disas_ctx = disas_context_create(file); - if (disas_ctx) { - disas_warned_funcs(disas_ctx); - disas_context_destroy(disas_ctx); - } + disas_warned_funcs(disas_ctx); + } + + if (disas_ctx) { + disas_context_destroy(disas_ctx); + objtool_disas_ctx = NULL; } free_insns(file); diff --git a/tools/objtool/disas.c b/tools/objtool/disas.c index 89daa121b40b0..a030b06c121d2 100644 --- a/tools/objtool/disas.c +++ b/tools/objtool/disas.c @@ -303,7 +303,7 @@ void disas_context_destroy(struct disas_context *dctx) free(dctx); } -static char *disas_result(struct disas_context *dctx) +char *disas_result(struct disas_context *dctx) { return dctx->result; } @@ -311,8 +311,7 @@ static char *disas_result(struct disas_context *dctx) /* * Disassemble a single instruction. Return the size of the instruction. */ -static size_t disas_insn(struct disas_context *dctx, - struct instruction *insn) +size_t disas_insn(struct disas_context *dctx, struct instruction *insn) { disassembler_ftype disasm = dctx->disassembler; struct disassemble_info *dinfo = &dctx->info; diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h index ad9c73504b120..f96aabd7d54dc 100644 --- a/tools/objtool/include/objtool/check.h +++ b/tools/objtool/include/objtool/check.h @@ -141,4 +141,6 @@ struct instruction *next_insn_same_sec(struct objtool_file *file, struct instruc insn && insn->offset < sym->offset + sym->len; \ insn = next_insn_same_sec(file, insn)) +const char *objtool_disas_insn(struct instruction *insn); + #endif /* _CHECK_H */ diff --git a/tools/objtool/include/objtool/disas.h b/tools/objtool/include/objtool/disas.h index 3ec3ce2e4e6f0..1aee1fbe0bb97 100644 --- a/tools/objtool/include/objtool/disas.h +++ b/tools/objtool/include/objtool/disas.h @@ -17,6 +17,8 @@ void disas_warned_funcs(struct disas_context *dctx); int disas_info_init(struct disassemble_info *dinfo, int arch, int mach32, int mach64, const char *options); +size_t disas_insn(struct disas_context *dctx, struct instruction *insn); +char *disas_result(struct disas_context *dctx); #else /* DISAS */ @@ -38,6 +40,17 @@ static inline int disas_info_init(struct disassemble_info *dinfo, return -1; } +static inline size_t disas_insn(struct disas_context *dctx, + struct instruction *insn) +{ + return -1; +} + +static inline char *disas_result(struct disas_context *dctx) +{ + return NULL; +} + #endif /* DISAS */ #endif /* _DISAS_H */ diff --git a/tools/objtool/include/objtool/warn.h b/tools/objtool/include/objtool/warn.h index a1e3927d8e7ce..f32abc7b1be14 100644 --- a/tools/objtool/include/objtool/warn.h +++ b/tools/objtool/include/objtool/warn.h @@ -77,9 +77,11 @@ static inline char *offstr(struct section *sec, unsigned long offset) #define WARN_INSN(insn, format, ...) \ ({ \ struct instruction *_insn = (insn); \ - if (!_insn->sym || !_insn->sym->warned) \ + if (!_insn->sym || !_insn->sym->warned) { \ WARN_FUNC(_insn->sec, _insn->offset, format, \ ##__VA_ARGS__); \ + BT_INSN(_insn, ""); \ + } \ if (_insn->sym) \ _insn->sym->warned = 1; \ }) @@ -87,10 +89,14 @@ static inline char *offstr(struct section *sec, unsigned long offset) #define BT_INSN(insn, format, ...) \ ({ \ if (opts.verbose || opts.backtrace) { \ - struct instruction *_insn = (insn); \ - char *_str = offstr(_insn->sec, _insn->offset); \ - WARN(" %s: " format, _str, ##__VA_ARGS__); \ - free(_str); \ + struct instruction *__insn = (insn); \ + char *_str = offstr(__insn->sec, __insn->offset); \ + const char *_istr = objtool_disas_insn(__insn); \ + int _len; \ + _len = snprintf(NULL, 0, " %s: " format, _str, ##__VA_ARGS__); \ + _len = (_len < 50) ? 50 - _len : 0; \ + WARN(" %s: " format " %*s%s", _str, ##__VA_ARGS__, _len, "", _istr); \ + free(_str); \ } \ }) -- 2.47.3