From: Steven Rostedt <rostedt@goodmis.org>
To: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: Petr Mladek <pmladek@suse.com>,
Joe Lawrence <joe.lawrence@redhat.com>,
Jiri Kosina <jikos@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
"live-patching@vger.kernel.org" <live-patching@vger.kernel.org>,
Miroslav Benes <mbenes@suse.cz>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH v2 11/13] powerpc/ftrace: directly call of function graph tracer by ftrace caller
Date: Mon, 14 Feb 2022 14:03:04 -0500 [thread overview]
Message-ID: <20220214140304.04d1e8a8@gandalf.local.home> (raw)
In-Reply-To: <1644859156.qdgqumennn.naveen@linux.ibm.com>
On Mon, 14 Feb 2022 22:54:23 +0530
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote:
> For x86, commit 0c0593b45c9b4e ("x86/ftrace: Make function graph use
> ftrace directly") also adds recursion check before the call to
> function_graph_enter() in prepare_ftrace_return(). Do we need that on
> powerpc as well?
Yes. The function_graph_enter() does not provide any recursion protection,
so if it were to call something that gets function graph traced, it will
crash the machine.
-- Steve
WARNING: multiple messages have this Message-ID (diff)
From: Steven Rostedt <rostedt@goodmis.org>
To: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>,
Jiri Kosina <jikos@kernel.org>,
Joe Lawrence <joe.lawrence@redhat.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Miroslav Benes <mbenes@suse.cz>, Ingo Molnar <mingo@redhat.com>,
Petr Mladek <pmladek@suse.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"live-patching@vger.kernel.org" <live-patching@vger.kernel.org>
Subject: Re: [PATCH v2 11/13] powerpc/ftrace: directly call of function graph tracer by ftrace caller
Date: Mon, 14 Feb 2022 14:03:04 -0500 [thread overview]
Message-ID: <20220214140304.04d1e8a8@gandalf.local.home> (raw)
In-Reply-To: <1644859156.qdgqumennn.naveen@linux.ibm.com>
On Mon, 14 Feb 2022 22:54:23 +0530
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote:
> For x86, commit 0c0593b45c9b4e ("x86/ftrace: Make function graph use
> ftrace directly") also adds recursion check before the call to
> function_graph_enter() in prepare_ftrace_return(). Do we need that on
> powerpc as well?
Yes. The function_graph_enter() does not provide any recursion protection,
so if it were to call something that gets function graph traced, it will
crash the machine.
-- Steve
next prev parent reply other threads:[~2022-02-14 19:03 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-20 16:37 [PATCH v2 00/13] Implement livepatch on PPC32 and more Christophe Leroy
2021-12-20 16:37 ` Christophe Leroy
2021-12-20 16:38 ` [PATCH v2 01/13] livepatch: Fix build failure on 32 bits processors Christophe Leroy
2021-12-20 16:38 ` Christophe Leroy
2021-12-22 13:47 ` Miroslav Benes
2021-12-22 13:47 ` Miroslav Benes
2022-01-04 19:35 ` Joe Lawrence
2022-01-04 19:35 ` Joe Lawrence
2021-12-20 16:38 ` [PATCH v2 02/13] tracing: Fix selftest config check for function graph start up test Christophe Leroy
2021-12-20 16:38 ` Christophe Leroy
2022-02-24 13:43 ` Christophe Leroy
2022-02-24 13:43 ` Christophe Leroy
2022-02-24 14:53 ` Steven Rostedt
2022-02-24 14:53 ` Steven Rostedt
2022-02-24 15:13 ` Christophe Leroy
2022-02-24 15:13 ` Christophe Leroy
2022-02-24 15:17 ` Steven Rostedt
2022-02-24 15:17 ` Steven Rostedt
2022-02-25 2:42 ` Michael Ellerman
2022-02-25 2:42 ` Michael Ellerman
2021-12-20 16:38 ` [PATCH v2 03/13] powerpc/module_32: Fix livepatching for RO modules Christophe Leroy
2021-12-20 16:38 ` Christophe Leroy
2022-01-04 19:44 ` Joe Lawrence
2022-01-04 19:44 ` Joe Lawrence
2021-12-20 16:38 ` [PATCH v2 04/13] powerpc/ftrace: Add support for livepatch to PPC32 Christophe Leroy
2021-12-20 16:38 ` Christophe Leroy
2021-12-22 14:00 ` Miroslav Benes
2021-12-22 14:00 ` Miroslav Benes
2021-12-20 16:38 ` [PATCH v2 05/13] powerpc/ftrace: Don't save again LR in ftrace_regs_caller() on PPC32 Christophe Leroy
2021-12-20 16:38 ` Christophe Leroy
2021-12-20 16:38 ` [PATCH v2 06/13] powerpc/ftrace: Simplify PPC32's return_to_handler() Christophe Leroy
2021-12-20 16:38 ` Christophe Leroy
2021-12-20 16:38 ` [PATCH v2 07/13] powerpc/ftrace: Prepare PPC32's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS Christophe Leroy
2021-12-20 16:38 ` Christophe Leroy
2021-12-20 16:38 ` [PATCH v2 08/13] powerpc/ftrace: Prepare PPC64's " Christophe Leroy
2021-12-20 16:38 ` Christophe Leroy
2022-02-14 15:19 ` Naveen N. Rao
2022-02-14 15:19 ` Naveen N. Rao
2021-12-20 16:38 ` [PATCH v2 09/13] powerpc/ftrace: Implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS Christophe Leroy
2021-12-20 16:38 ` Christophe Leroy
2021-12-22 14:19 ` Miroslav Benes
2021-12-22 14:19 ` Miroslav Benes
2021-12-22 14:19 ` Miroslav Benes
2022-02-14 15:25 ` Naveen N. Rao
2022-02-14 15:25 ` Naveen N. Rao
2022-02-15 8:00 ` Christophe Leroy
2022-02-15 8:00 ` Christophe Leroy
2022-02-15 11:05 ` Michael Ellerman
2022-02-15 11:05 ` Michael Ellerman
2022-02-15 13:36 ` Naveen N. Rao
2022-02-15 13:36 ` Naveen N. Rao
2022-02-15 14:28 ` Christophe Leroy
2022-02-15 14:28 ` Christophe Leroy
2022-02-15 14:51 ` Christophe Leroy
2022-02-15 14:51 ` Christophe Leroy
2022-02-15 16:25 ` Naveen N. Rao
2022-02-15 16:25 ` Naveen N. Rao
2022-02-16 13:04 ` Heiko Carstens
2022-02-16 13:04 ` Heiko Carstens
2022-02-16 13:27 ` Sven Schnelle
2022-02-16 13:27 ` Sven Schnelle
2022-02-15 14:38 ` Steven Rostedt
2022-02-15 14:38 ` Steven Rostedt
2022-02-15 16:26 ` Naveen N. Rao
2022-02-15 16:26 ` Naveen N. Rao
2021-12-20 16:38 ` [PATCH v2 10/13] powerpc/ftrace: Refactor ftrace_{en/dis}able_ftrace_graph_caller Christophe Leroy
2021-12-20 16:38 ` Christophe Leroy
2021-12-20 16:38 ` [PATCH v2 11/13] powerpc/ftrace: directly call of function graph tracer by ftrace caller Christophe Leroy
2021-12-20 16:38 ` Christophe Leroy
2022-02-14 17:24 ` Naveen N. Rao
2022-02-14 17:24 ` Naveen N. Rao
2022-02-14 19:03 ` Steven Rostedt [this message]
2022-02-14 19:03 ` Steven Rostedt
2021-12-20 16:38 ` [PATCH v2 12/13] powerpc/ftrace: Prepare ftrace_64_mprofile.S for reuse by PPC32 Christophe Leroy
2021-12-20 16:38 ` Christophe Leroy
2022-02-14 17:51 ` Naveen N. Rao
2022-02-14 17:51 ` Naveen N. Rao
2022-02-15 8:33 ` Christophe Leroy
2022-02-15 8:33 ` Christophe Leroy
2021-12-20 16:38 ` [PATCH v2 13/13] powerpc/ftrace: Remove ftrace_32.S Christophe Leroy
2021-12-20 16:38 ` Christophe Leroy
2022-02-11 7:41 ` [PATCH] Fixup for next-test 3a1a8f078670 ("powerpc/ftrace: Remove ftrace_32.S") Christophe Leroy
2022-02-11 7:41 ` Christophe Leroy
2022-02-16 12:26 ` [PATCH v2 00/13] Implement livepatch on PPC32 and more Michael Ellerman
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