From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Ilie Halip <ilie.halip@gmail.com>
Cc: linux-kernel@vger.kernel.org,
Nick Desaulniers <ndesaulniers@google.com>,
Rong Chen <rong.a.chen@intel.com>, Marco Elver <elver@google.com>,
Philip Li <philip.li@intel.com>, Borislav Petkov <bp@alien8.de>,
kasan-dev@googlegroups.com, x86@kernel.org,
clang-built-linux@googlegroups.com,
Peter Zijlstra <peterz@infradead.org>,
Nathan Chancellor <natechancellor@gmail.com>
Subject: Re: [PATCH] objtool: ignore unreachable trap after call to noreturn functions
Date: Thu, 17 Sep 2020 17:16:20 -0500 [thread overview]
Message-ID: <20200917221620.n4vavakienaqvqvi@treble> (raw)
In-Reply-To: <20200917084905.1647262-1-ilie.halip@gmail.com>
On Thu, Sep 17, 2020 at 11:49:04AM +0300, Ilie Halip wrote:
> 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.
>
> objtool silences similar warnings (trap after dead end instructions), 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>
> Signed-off-by: Ilie Halip <ilie.halip@gmail.com>
The patch looks good to me. Which versions of Clang do the trap after
noreturn call? It would be good to have that in the commit message.
--
Josh
next prev parent reply other threads:[~2020-09-17 22:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-17 8:49 [PATCH] objtool: ignore unreachable trap after call to noreturn functions Ilie Halip
2020-09-17 18:15 ` Nick Desaulniers
2020-09-17 22:16 ` Josh Poimboeuf [this message]
2020-09-18 5:35 ` Ilie Halip
2020-09-18 15:51 ` Josh Poimboeuf
2020-09-19 6:41 ` [PATCH v2] " Ilie Halip
2020-09-19 11:02 ` Sedat Dilek
2020-09-21 15:19 ` Josh Poimboeuf
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