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From: Peter Zijlstra <peterz@infradead.org>
To: Jessica Yu <jeyu@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	mhiramat@kernel.org, bristot@redhat.com, jbaron@akamai.com,
	torvalds@linux-foundation.org, tglx@linutronix.de,
	mingo@kernel.org, namit@vmware.com, hpa@zytor.com,
	luto@kernel.org, ard.biesheuvel@linaro.org, jpoimboe@redhat.com,
	mbenes@suse.cz
Subject: Re: [PATCH v3 5/6] x86/ftrace: Use text_poke()
Date: Tue, 15 Oct 2019 16:11:11 +0200
Message-ID: <20191015141111.GP2359@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20191015135634.GK2328@hirez.programming.kicks-ass.net>

On Tue, Oct 15, 2019 at 03:56:34PM +0200, Peter Zijlstra wrote:
> On Tue, Oct 15, 2019 at 03:07:40PM +0200, Jessica Yu wrote:

> > > Once this ftrace thing is sorted, we'll change x86 to _refuse_ to make
> > > executable (kernel) memory writable.
> > 
> > Not sure if relevant, but just thought I'd clarify: IIRC,
> > klp_module_coming() is not poking the coming module, but it calls
> > module_enable_ro() on itself (the livepatch module) so it can apply
> > relocations and such on the new code, which lives inside the livepatch
> > module, and it needs to possibly do this numerous times over the
> > lifetime of the patch module for any coming module it is responsible
> > for patching (i.e., call module_enable_ro() on the patch module, not
> > necessarily the coming module). So I am not be sure why
> > klp_module_coming() should be moved before complete_formation(). I
> > hope I'm remembering the details correctly, livepatch folks feel free
> > to chime in if I'm incorrect here.
> 
> You mean it does module_disable_ro() ? That would be broken and it needs
> to be fixed. Can some livepatch person explain what it does and why?

mbenes confirmed; what would be needed is for the live-patch module to
have all module dependent parts to be in their own section and have the
sections be page-aligned. Then we can do the protection on sections
instead of on the whole module.

Damn, and I thought I was so close to getting W^X sorted :/

  reply index

Thread overview: 128+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-07  9:02 [RESEND] everything text-poke: ftrace, modules, static_call and jump_label Peter Zijlstra
2019-10-07  8:17 ` [PATCH v3 0/6] Rewrite x86/ftrace to use text_poke() Peter Zijlstra
2019-10-07  8:17   ` [PATCH v3 1/6] x86/alternatives: Teach text_poke_bp() to emulate instructions Peter Zijlstra
2019-10-08 14:29     ` Borislav Petkov
2019-10-08 14:40       ` Steven Rostedt
2019-10-08 14:50         ` Borislav Petkov
2019-10-08 14:48       ` Peter Zijlstra
2019-10-08 14:54         ` Borislav Petkov
2019-10-08 15:04           ` Steven Rostedt
2019-10-08 15:24             ` Borislav Petkov
2019-10-09 12:03     ` Daniel Bristot de Oliveira
2019-10-07  8:17   ` [PATCH v3 2/6] x86/alternatives: Update int3_emulate_push() comment Peter Zijlstra
2019-10-07  8:17   ` [PATCH v3 3/6] x86/alternatives,jump_label: Provide better text_poke() batching interface Peter Zijlstra
2019-10-09 12:04     ` Daniel Bristot de Oliveira
2019-10-07  8:17   ` [PATCH v3 4/6] x86/alternatives: Add and use text_gen_insn() helper Peter Zijlstra
2019-10-08  6:23     ` Masami Hiramatsu
2019-10-08  8:15       ` Peter Zijlstra
2019-10-07  8:17   ` [PATCH v3 5/6] x86/ftrace: Use text_poke() Peter Zijlstra
2019-10-08 14:43     ` Steven Rostedt
2019-10-08 17:11       ` Peter Zijlstra
2019-10-08 17:27         ` Steven Rostedt
2019-10-10  2:41       ` Steven Rostedt
2019-10-10  9:20         ` Peter Zijlstra
2019-10-10 13:19           ` Steven Rostedt
2019-10-10 14:05             ` Peter Zijlstra
2019-10-10 15:54               ` Steven Rostedt
2019-10-10 17:28                 ` Peter Zijlstra
2019-10-10 17:48                   ` Steven Rostedt
2019-10-11 10:45                     ` Peter Zijlstra
2019-10-11 10:47                       ` Peter Zijlstra
2019-10-11 10:50                         ` Peter Zijlstra
2019-10-11 12:59                   ` Peter Zijlstra
2019-10-11 13:33                     ` Steven Rostedt
2019-10-11 13:45                       ` Peter Zijlstra
2019-10-15 13:07                     ` Jessica Yu
2019-10-15 13:56                       ` Peter Zijlstra
2019-10-15 14:11                         ` Peter Zijlstra [this message]
2019-10-15 14:13                         ` Miroslav Benes
2019-10-15 15:06                           ` Joe Lawrence
2019-10-15 15:31                             ` Jessica Yu
2019-10-15 22:17                               ` Joe Lawrence
2019-10-15 22:27                                 ` Steven Rostedt
2019-10-16  7:42                                   ` Peter Zijlstra
2019-10-16 10:15                                     ` Miroslav Benes
2019-10-21 15:05                                     ` Josh Poimboeuf
2020-01-20 16:50                                       ` Josh Poimboeuf
2020-01-21  8:35                                         ` Miroslav Benes
2020-01-21 16:10                                           ` Josh Poimboeuf
2020-01-22 10:09                                             ` Miroslav Benes
2020-01-22 21:42                                               ` Josh Poimboeuf
2020-01-28  9:28                                                 ` Miroslav Benes
2020-01-28 15:00                                                   ` Josh Poimboeuf
2020-01-28 15:40                                                     ` Petr Mladek
2020-01-28 17:02                                                       ` Josh Poimboeuf
2020-01-29  0:46                                                         ` Jiri Kosina
2020-01-29  2:17                                                           ` Josh Poimboeuf
2020-01-29  3:14                                                             ` Jiri Kosina
2020-01-29 12:28                                                         ` Miroslav Benes
2020-01-29 15:59                                                           ` Josh Poimboeuf
2020-01-30  9:53                                                             ` Petr Mladek
2020-01-30 14:17                                                               ` Josh Poimboeuf
2020-01-31  7:17                                                                 ` Petr Mladek
2020-01-22 12:15                                             ` Miroslav Benes
2020-01-22 15:05                                               ` Miroslav Benes
2020-01-22 22:03                                                 ` Josh Poimboeuf
2020-01-23 10:19                                                   ` Martin Jambor
2019-10-16  7:49                                   ` Peter Zijlstra
2019-10-16 10:20                                     ` Miroslav Benes
2019-10-16 13:29                                       ` Miroslav Benes
2019-10-18 13:03                                         ` Jessica Yu
2019-10-18 13:40                                           ` Petr Mladek
2019-10-21 14:14                                             ` Jessica Yu
2019-10-21 15:31                                             ` Josh Poimboeuf
2019-10-22  8:27                                           ` Miroslav Benes
2019-10-22 14:31                                             ` Josh Poimboeuf
2019-10-23  9:04                                               ` Miroslav Benes
2019-10-16  6:51                             ` Miroslav Benes
2019-10-16  9:23                               ` Peter Zijlstra
2019-10-16  9:36                                 ` Jessica Yu
2019-10-16  9:51                                   ` Peter Zijlstra
2019-10-16 12:39                               ` Peter Zijlstra
2019-10-22  8:45                                 ` Miroslav Benes
2019-10-15 14:42                         ` Peter Zijlstra
2019-10-15 18:31                           ` Peter Zijlstra
2019-10-15 15:51                         ` Jessica Yu
2019-10-15 13:28                     ` Steven Rostedt
2019-10-15 13:42                       ` Peter Zijlstra
2019-10-15 16:09                       ` Jessica Yu
2019-10-07  8:17   ` [PATCH v3 6/6] x86/mm: Remove set_kernel_text_r[ow]() Peter Zijlstra
2019-10-08 15:07   ` [PATCH v3 0/6] Rewrite x86/ftrace to use text_poke() Steven Rostedt
2019-10-07  8:25 ` [PATCH v2 0/4] Propagate module notifier errors Peter Zijlstra
2019-10-07  8:25   ` [PATCH v2 1/4] notifier: Fix broken error handling pattern Peter Zijlstra
2019-10-10 22:01     ` Rafael J. Wysocki
2019-10-07  8:25   ` [PATCH v2 2/4] module: Fix up module_notifier return values Peter Zijlstra
2019-10-23 19:25     ` Steven Rostedt
2019-10-07  8:25   ` [PATCH v2 3/4] module: Properly propagate MODULE_STATE_COMING failure Peter Zijlstra
2019-10-08 13:08     ` Miroslav Benes
2019-10-07  8:25   ` [PATCH v2 4/4] jump_label,module: Fix module lifetime for __jump_label_mod_text_reserved Peter Zijlstra
2019-10-23 19:29     ` Steven Rostedt
2019-10-07  8:27 ` [PATCH v2 00/13] Add static_call() Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 01/13] compiler.h: Make __ADDRESSABLE() symbol truly unique Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 02/13] static_call: Add basic static call infrastructure Peter Zijlstra
2019-10-07 11:33     ` Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 03/13] static_call: Add inline " Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 04/13] static_call: Avoid kprobes on inline static_call()s Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 05/13] x86/static_call: Add out-of-line static call implementation Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 06/13] x86/static_call: Add inline static call implementation for x86-64 Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 07/13] static_call: Simple self-test Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 08/13] tracepoints: Use static_call Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 09/13] x86/alternatives: Teach text_poke_bp() to emulate RET Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 10/13] static_call: Add static_cond_call() Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 11/13] static_call: Handle tail-calls Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 12/13] static_call: Allow early init Peter Zijlstra
2019-10-07  8:27   ` [RFC][PATCH v2 13/13] x86/perf, static_call: Optimize x86_pmu methods Peter Zijlstra
2019-10-07 11:33   ` [PATCH v2 00/13] Add static_call() Peter Zijlstra
2019-10-07  8:44 ` [RFC][PATCH 0/9] Variable size jump_label support Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 1/9] jump_label, x86: Strip ASM " Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 2/9] jump_label, x86: Factor out the __jump_table generation Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 3/9] jump_label, x86: Remove init NOP optimization Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 4/9] jump_label, x86: Improve error when we fail expected text Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 5/9] jump_label, x86: Introduce jump_entry_size() Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 6/9] jump_label, x86: Add variable length patching support Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 7/9] jump_label,objtool: Validate variable size jump labels Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 8/9] jump_label,objtool: Generate possible statistics Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 9/9] jump_label, x86: Enable JMP8/NOP2 support Peter Zijlstra
2019-10-07 12:07   ` [RFC][PATCH 0/9] Variable size jump_label support Peter Zijlstra
2019-10-07 12:55     ` Ingo Molnar
2019-10-07 15:08       ` Steven Rostedt

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