From: Peter Zijlstra <peterz@infradead.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
X86 ML <x86@kernel.org>, Nadav Amit <nadav.amit@gmail.com>,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Song Liu <songliubraving@fb.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>
Subject: Re: [PATCH 00/10] ftrace: Add register_ftrace_direct()
Date: Mon, 11 Nov 2019 09:47:28 +0100 [thread overview]
Message-ID: <20191111084728.GO4131@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20191108225100.ea3bhsbdf6oerj6g@treble>
On Fri, Nov 08, 2019 at 04:51:00PM -0600, Josh Poimboeuf wrote:
> From: Josh Poimboeuf <jpoimboe@redhat.com>
> Subject: [PATCH] ftrace/x86: Tell objtool to ignore nondeterministic ftrace stack layout
>
> Objtool complains about the new ftrace direct trampoline code:
>
> arch/x86/kernel/ftrace_64.o: warning: objtool: ftrace_regs_caller()+0x190: stack state mismatch: cfa1=7+16 cfa2=7+24
>
> Typically, code has a deterministic stack layout, such that at a given
> instruction address, the stack frame size is always the same.
>
> That's not the case for the new ftrace_regs_caller() code after it
> adjusts the stack for the direct case. Just plead ignorance and assume
> it's always the non-direct path. Note this creates a tiny window for
> ORC to get confused.
How is that not a problem for livepatch?
next prev parent reply other threads:[~2019-11-11 8:47 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-08 21:28 [PATCH 00/10] ftrace: Add register_ftrace_direct() Steven Rostedt
2019-11-08 21:28 ` [PATCH 01/10] ftrace: Separate out the copying of a ftrace_hash from __ftrace_hash_move() Steven Rostedt
2019-11-08 21:28 ` [PATCH 02/10] ftrace: Separate out functionality from ftrace_location_range() Steven Rostedt
2019-11-08 21:28 ` [PATCH 03/10] ftrace: Add register_ftrace_direct() Steven Rostedt
2019-11-09 2:29 ` Alexei Starovoitov
2019-11-09 12:33 ` Steven Rostedt
2019-11-14 18:29 ` Steven Rostedt
2019-11-14 18:34 ` Alexei Starovoitov
2019-11-14 18:48 ` Steven Rostedt
2019-11-14 19:05 ` Steven Rostedt
2019-11-13 14:13 ` Miroslav Benes
2019-11-13 14:34 ` Steven Rostedt
2019-11-08 21:28 ` [PATCH 04/10] ftrace: Add ftrace_find_direct_func() Steven Rostedt
2019-11-08 21:28 ` [PATCH 05/10] ftrace: Add sample module that uses register_ftrace_direct() Steven Rostedt
2019-11-08 21:28 ` [PATCH 06/10] ftrace/selftest: Add tests to test register_ftrace_direct() Steven Rostedt
2019-11-08 21:28 ` [PATCH 07/10] ftrace: Add another example of register_ftrace_direct() use case Steven Rostedt
2019-11-08 21:28 ` [PATCH 08/10] ftrace/selftests: Update the direct call selftests to test two direct calls Steven Rostedt
2019-11-08 21:28 ` [PATCH 09/10] ftrace/x86: Add register_ftrace_direct() for custom trampolines Steven Rostedt
2019-11-14 15:34 ` Miroslav Benes
2019-11-14 16:19 ` Steven Rostedt
2019-11-15 9:32 ` Miroslav Benes
2019-11-08 21:28 ` [PATCH 10/10] ftrace/x86: Add a counter to test function_graph with direct Steven Rostedt
2019-11-08 22:51 ` [PATCH 00/10] ftrace: Add register_ftrace_direct() Josh Poimboeuf
2019-11-09 1:00 ` Steven Rostedt
2019-11-11 8:47 ` Peter Zijlstra [this message]
2019-11-11 14:15 ` Josh Poimboeuf
2019-11-13 15:10 ` Miroslav Benes
2019-11-13 16:31 ` Steven Rostedt
2019-11-14 9:05 ` Miroslav Benes
2019-11-14 14:36 ` Steven Rostedt
2019-11-14 15:42 ` Miroslav Benes
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