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From: Peter Zijlstra <peterz@infradead.org>
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Florian Weimer <fw@deneb.enyo.de>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Sami Tolvanen <samitolvanen@google.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Matt Mullins <mmullins@mmlx.us>, Ingo Molnar <mingo@redhat.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Dmitry Vyukov <dvyukov@google.com>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>, netdev <netdev@vger.kernel.org>,
	bpf <bpf@vger.kernel.org>, Kees Cook <keescook@chromium.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	linux-toolchains@vger.kernel.org
Subject: Re: violating function pointer signature
Date: Thu, 19 Nov 2020 09:21:57 +0100	[thread overview]
Message-ID: <20201119082157.GD3121392@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20201118194837.GO2672@gate.crashing.org>

On Wed, Nov 18, 2020 at 01:48:37PM -0600, Segher Boessenkool wrote:

> If you have at most four or so args, what you wnat to do will work on
> all systems the kernel currently supports, as far as I can tell.  It
> is not valid C, and none of the compilers have an extension for this
> either.  But it will likely work.

So this is where we rely on the calling convention being caller-cleanup
(cdecl has that).

I looked at the GCC preprocessor symbols but couldn't find anything that
seems relevant to the calling convention in use, so barring that, the
best option might to be have a boot-time self-test that triggers this.
Then we'll quickly know if all architectures handle this correctly.

  parent reply	other threads:[~2020-11-19  8:22 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-16 22:51 [PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation Steven Rostedt
2020-11-16 23:16 ` Steven Rostedt
2020-11-17 19:15 ` Mathieu Desnoyers
2020-11-17 19:21   ` Steven Rostedt
2020-11-17 19:47     ` Mathieu Desnoyers
2020-11-17 20:34       ` Steven Rostedt
2020-11-17 20:58         ` Steven Rostedt
2020-11-17 21:22           ` Mathieu Desnoyers
2020-11-17 22:16             ` Steven Rostedt
2020-11-17 23:08               ` Mathieu Desnoyers
2020-11-18  1:11                 ` Steven Rostedt
2020-11-17 21:08         ` Mathieu Desnoyers
2020-11-18 13:21         ` violating function pointer signature Peter Zijlstra
2020-11-18 13:59           ` Florian Weimer
2020-11-18 14:12             ` Peter Zijlstra
2020-11-18 14:18               ` Florian Weimer
2020-11-18 14:34                 ` [PATCH v3] tracepoint: Do not fail unregistering a probe due to memory allocation Steven Rostedt
2020-11-24  5:59                   ` Matt Mullins
2020-11-18 14:22             ` violating function pointer signature Steven Rostedt
2020-11-18 19:46               ` Alexei Starovoitov
2020-11-18 20:02                 ` Steven Rostedt
2020-11-18 14:02           ` Steven Rostedt
2020-11-18 16:01             ` Mathieu Desnoyers
2020-11-18 16:19               ` David Laight
2020-11-18 16:50           ` Nick Desaulniers
2020-11-18 17:17             ` Steven Rostedt
2020-11-18 18:12               ` Segher Boessenkool
2020-11-18 18:31                 ` Florian Weimer
2020-11-18 18:55                   ` Segher Boessenkool
2020-11-18 18:58                   ` Steven Rostedt
2020-11-18 18:59                     ` Steven Rostedt
2020-11-18 19:11                     ` Segher Boessenkool
2020-11-18 19:33                       ` Steven Rostedt
2020-11-18 19:48                         ` Segher Boessenkool
2020-11-18 20:44                           ` Steven Rostedt
2020-11-19  8:21                           ` Peter Zijlstra [this message]
2020-11-19  8:36                       ` Peter Zijlstra
2020-11-19 14:37                         ` Segher Boessenkool
2020-11-19 14:59                           ` Steven Rostedt
2020-11-19 16:35                             ` Segher Boessenkool
2020-11-19 17:42                               ` David Laight
2020-11-19 19:27                                 ` Segher Boessenkool
2020-11-19 17:04                             ` Alexei Starovoitov
2020-11-19 17:30                               ` Steven Rostedt
2020-11-20  1:31                               ` Nick Desaulniers
2020-11-17 21:33 ` [PATCH] tracepoint: Do not fail unregistering a probe due to memory allocation Kees Cook
2020-11-17 22:19   ` Steven Rostedt
2020-11-17 23:12     ` Mathieu Desnoyers

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