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Date: Wed, 13 Oct 2021 12:03:23 -0700
From: Kees Cook <keescook@chromium.org>
To: Sami Tolvanen <samitolvanen@google.com>
Cc: x86@kernel.org, Josh Poimboeuf <jpoimboe@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Sedat Dilek <sedat.dilek@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org,
	llvm@lists.linux.dev
Subject: Re: [PATCH v5 05/15] tracepoint: Exclude tp_stub_func from CFI
 checking
Message-ID: <202110131203.78C3851CA9@keescook>
References: <20211013181658.1020262-1-samitolvanen@google.com>
 <20211013181658.1020262-6-samitolvanen@google.com>
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In-Reply-To: <20211013181658.1020262-6-samitolvanen@google.com>

On Wed, Oct 13, 2021 at 11:16:48AM -0700, Sami Tolvanen wrote:
> If allocate_probes fails, func_remove replaces the old function
> with a pointer to tp_stub_func, which is called using a mismatching
> function pointer that will always trip indirect call checks with
> CONFIG_CFI_CLANG. Use DEFINE_CFI_IMMEDATE_RETURN_STUB to define
> tp_stub_func to allow it to pass CFI checking.
> 
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook