From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Andy Lutomirski <luto@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
Jason Baron <jbaron@akamai.com>, Jiri Kosina <jkosina@suse.cz>,
David Laight <David.Laight@ACULAB.COM>,
Borislav Petkov <bp@alien8.de>, Julia Cartwright <julia@ni.com>,
Jessica Yu <jeyu@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
Nadav Amit <namit@vmware.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Edward Cree <ecree@solarflare.com>,
Daniel Bristot de Oliveira <bristot@redhat.com>
Subject: Re: [PATCH 03/15] x86/kprobes: Fix frame pointer annotations
Date: Fri, 7 Jun 2019 09:36:02 -0400 [thread overview]
Message-ID: <20190607133602.os7st57epo3otbc4@treble> (raw)
In-Reply-To: <20190607220210.328ed88f2f7598e757c3564f@kernel.org>
On Fri, Jun 07, 2019 at 10:02:10PM +0900, Masami Hiramatsu wrote:
> On Wed, 05 Jun 2019 15:07:56 +0200
> Peter Zijlstra <peterz@infradead.org> wrote:
>
> > The kprobe trampolines have a FRAME_POINTER annotation that makes no
> > sense. It marks the frame in the middle of pt_regs, at the place of
> > saving BP.
>
> commit ee213fc72fd67 introduced this code, and this is for unwinder which
> uses frame pointer. I think current code stores the address of previous
> (original context's) frame pointer into %rbp. So with that, if unwinder
> tries to decode frame pointer, it can get the original %rbp value,
> instead of &pt_regs from current %rbp.
>
> >
> > Change it to mark the pt_regs frame as per the ENCODE_FRAME_POINTER
> > from the respective entry_*.S.
> >
>
> With this change, I think stack unwinder can not get the original %rbp
> value. Peter, could you check the above commit?
The unwinder knows how to decode the encoded frame pointer. So it can
find regs by decoding the new rbp value, and it also knows that regs->bp
is the original rbp value.
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
--
Josh
next prev parent reply other threads:[~2019-06-07 13:36 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-05 13:07 [PATCH 00/15] x86 cleanups and static_call() Peter Zijlstra
2019-06-05 13:07 ` [PATCH 01/15] x86/entry/32: Clean up return from interrupt preemption path Peter Zijlstra
2019-06-07 14:21 ` Josh Poimboeuf
2019-06-05 13:07 ` [PATCH 02/15] x86: Move ENCODE_FRAME_POINTER to asm/frame.h Peter Zijlstra
2019-06-07 14:24 ` Josh Poimboeuf
2019-06-05 13:07 ` [PATCH 03/15] x86/kprobes: Fix frame pointer annotations Peter Zijlstra
2019-06-07 13:02 ` Masami Hiramatsu
2019-06-07 13:36 ` Josh Poimboeuf [this message]
2019-06-07 15:21 ` Masami Hiramatsu
2019-06-11 8:12 ` Peter Zijlstra
2019-06-05 13:07 ` [PATCH 04/15] x86/ftrace: Add pt_regs frame annotations Peter Zijlstra
2019-06-07 14:45 ` Josh Poimboeuf
2019-06-05 13:07 ` [PATCH 05/15] x86_32: Provide consistent pt_regs Peter Zijlstra
2019-06-07 13:13 ` Masami Hiramatsu
2019-06-07 19:32 ` Josh Poimboeuf
2019-06-11 8:14 ` Peter Zijlstra
2019-06-05 13:07 ` [PATCH 06/15] x86_32: Allow int3_emulate_push() Peter Zijlstra
2019-06-05 13:08 ` [PATCH 07/15] x86: Add int3_emulate_call() selftest Peter Zijlstra
2019-06-10 16:52 ` Josh Poimboeuf
2019-06-10 16:57 ` Andy Lutomirski
2019-06-11 8:17 ` Peter Zijlstra
2019-06-05 13:08 ` [PATCH 08/15] x86/alternatives: Teach text_poke_bp() to emulate instructions Peter Zijlstra
2019-06-07 5:41 ` Nadav Amit
2019-06-07 8:20 ` Peter Zijlstra
2019-06-07 14:27 ` Masami Hiramatsu
2019-06-07 15:47 ` Masami Hiramatsu
2019-06-07 17:34 ` Peter Zijlstra
2019-06-07 17:48 ` Linus Torvalds
2019-06-11 10:44 ` Peter Zijlstra
2019-06-07 18:10 ` Andy Lutomirski
2019-06-07 20:22 ` hpa
2019-06-11 8:03 ` Peter Zijlstra
2019-06-11 12:08 ` Peter Zijlstra
2019-06-11 12:34 ` Peter Zijlstra
2019-06-11 12:42 ` Peter Zijlstra
2019-06-11 15:22 ` Steven Rostedt
2019-06-11 15:52 ` Steven Rostedt
2019-06-11 15:55 ` Peter Zijlstra
2019-06-12 19:44 ` Nadav Amit
2019-06-17 14:42 ` Peter Zijlstra
2019-06-17 17:06 ` Nadav Amit
2019-06-17 17:25 ` Andy Lutomirski
2019-06-17 19:26 ` Peter Zijlstra
2019-06-11 15:54 ` Andy Lutomirski
2019-06-11 16:11 ` Steven Rostedt
2019-06-17 14:31 ` Peter Zijlstra
2019-06-12 17:09 ` Peter Zijlstra
2019-06-10 16:57 ` Josh Poimboeuf
2019-06-11 15:14 ` Steven Rostedt
2019-06-11 15:52 ` Peter Zijlstra
2019-06-11 16:21 ` Peter Zijlstra
2019-06-12 14:44 ` Peter Zijlstra
2019-06-05 13:08 ` [PATCH 09/15] compiler.h: Make __ADDRESSABLE() symbol truly unique Peter Zijlstra
2019-06-05 13:08 ` [PATCH 10/15] static_call: Add basic static call infrastructure Peter Zijlstra
2019-06-06 22:44 ` Nadav Amit
2019-06-07 8:28 ` Peter Zijlstra
2019-06-07 8:49 ` Ard Biesheuvel
2019-06-07 16:33 ` Andy Lutomirski
2019-06-07 16:58 ` Nadav Amit
2019-10-02 13:54 ` Peter Zijlstra
2019-10-02 20:48 ` Josh Poimboeuf
2019-06-05 13:08 ` [PATCH 11/15] static_call: Add inline " Peter Zijlstra
2019-06-06 22:24 ` Nadav Amit
2019-06-07 8:37 ` Peter Zijlstra
2019-06-07 16:35 ` Nadav Amit
2019-06-07 17:41 ` Peter Zijlstra
2019-06-10 17:19 ` Josh Poimboeuf
2019-06-10 18:33 ` Nadav Amit
2019-06-10 18:42 ` Josh Poimboeuf
2019-10-01 12:00 ` Peter Zijlstra
2019-06-05 13:08 ` [PATCH 12/15] x86/static_call: Add out-of-line static call implementation Peter Zijlstra
2019-06-07 6:13 ` Nadav Amit
2019-06-07 7:51 ` Steven Rostedt
2019-06-07 8:38 ` Peter Zijlstra
2019-06-07 8:52 ` Peter Zijlstra
2019-06-05 13:08 ` [PATCH 13/15] x86/static_call: Add inline static call implementation for x86-64 Peter Zijlstra
2019-06-07 5:50 ` Nadav Amit
2019-06-10 18:33 ` Josh Poimboeuf
2019-06-10 18:45 ` Nadav Amit
2019-06-10 18:55 ` Josh Poimboeuf
2019-06-10 19:20 ` Nadav Amit
2019-10-01 14:43 ` Peter Zijlstra
2019-06-05 13:08 ` [PATCH 14/15] static_call: Simple self-test module Peter Zijlstra
2019-06-10 17:24 ` Josh Poimboeuf
2019-06-11 8:29 ` Peter Zijlstra
2019-06-11 13:02 ` Josh Poimboeuf
2019-06-05 13:08 ` [PATCH 15/15] tracepoints: Use static_call Peter Zijlstra
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