Ilie Halip 14db1f0a93 objtool: Ignore unreachable trap after call to noreturn functions
With CONFIG_UBSAN_TRAP enabled, the compiler may insert a trap
instruction after a call to a noreturn function. In this case, objtool
warns that the UD2 instruction is unreachable.

This is a behavior seen with Clang, from the oldest version capable of
building the mainline x64_64 kernel (9.0), to the latest experimental
version (12.0).

Objtool silences similar warnings (trap after dead end instructions), so
so expand that check to include dead end functions.

Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Rong Chen <rong.a.chen@intel.com>
Cc: Marco Elver <elver@google.com>
Cc: Philip Li <philip.li@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: kasan-dev@googlegroups.com
Cc: x86@kernel.org
Cc: clang-built-linux@googlegroups.com
BugLink: https://github.com/ClangBuiltLinux/linux/issues/1148
Link: https://lore.kernel.org/lkml/CAKwvOdmptEpi8fiOyWUo=AiZJiX+Z+VHJOM2buLPrWsMTwLnyw@mail.gmail.com
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Ilie Halip <ilie.halip@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-21 10:20:10 -05:00
..
2020-04-03 13:12:26 -07:00
2020-04-02 17:57:10 +01:00
2020-08-30 10:56:12 -07:00
2020-08-19 14:11:44 +02:00
2020-08-11 14:34:17 -07:00