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| author | Josh Poimboeuf <jpoimboe@kernel.org> | 2023-04-18 14:27:50 -0700 |
|---|---|---|
| committer | Josh Poimboeuf <jpoimboe@kernel.org> | 2023-05-16 06:31:53 -0700 |
| commit | fedb724c3db5490234ddde0103811c28c2fedae0 (patch) | |
| tree | b3d61b25d2c2ba469a84f4aa2abc08270e2a42f5 /tools/objtool | |
| parent | ced23d2e3762ecfb859ae65d3a351218edff7205 (diff) | |
| download | linux-fedb724c3db5490234ddde0103811c28c2fedae0.tar.gz linux-fedb724c3db5490234ddde0103811c28c2fedae0.tar.bz2 linux-fedb724c3db5490234ddde0103811c28c2fedae0.zip | |
objtool: Detect missing __noreturn annotations
Most "unreachable instruction" warnings these days seem to actually be
the result of a missing __noreturn annotation. Add an explicit check
for that.
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/6e2b93d8c65eaed6c4166a358269dc0ef01f890c.1681853186.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Diffstat (limited to 'tools/objtool')
| -rw-r--r-- | tools/objtool/Documentation/objtool.txt | 6 | ||||
| -rw-r--r-- | tools/objtool/check.c | 14 |
2 files changed, 19 insertions, 1 deletions
diff --git a/tools/objtool/Documentation/objtool.txt b/tools/objtool/Documentation/objtool.txt index 9ec8cbf20668..f9345e0ce740 100644 --- a/tools/objtool/Documentation/objtool.txt +++ b/tools/objtool/Documentation/objtool.txt @@ -303,6 +303,12 @@ the objtool maintainers. If it's not actually in a callable function (e.g. kernel entry code), change ENDPROC to END. +3. file.o: warning: objtool: foo+0x48c: bar() is missing a __noreturn annotation + + The call from foo() to bar() doesn't return, but bar() is missing the + __noreturn annotation. NOTE: In addition to adding the __noreturn + annotation, the function name also needs to be added to + 'global_noreturns' in tools/objtool/check.c. 4. file.o: warning: objtool: func(): can't find starting instruction or diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 71985f3a6fa6..8d1b4226608c 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -4507,7 +4507,8 @@ static int validate_sls(struct objtool_file *file) static int validate_reachable_instructions(struct objtool_file *file) { - struct instruction *insn; + struct instruction *insn, *prev_insn; + struct symbol *call_dest; int warnings = 0; if (file->ignore_unreachables) @@ -4517,6 +4518,17 @@ static int validate_reachable_instructions(struct objtool_file *file) if (insn->visited || ignore_unreachable_insn(file, insn)) continue; + prev_insn = prev_insn_same_sec(file, insn); + if (prev_insn && prev_insn->dead_end) { + call_dest = insn_call_dest(prev_insn); + if (call_dest) { + WARN_INSN(insn, "%s() is missing a __noreturn annotation", + call_dest->name); + warnings++; + continue; + } + } + WARN_INSN(insn, "unreachable instruction"); warnings++; } |