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From: 王贇 <yun.wang@linux.alibaba.com>
To: Guo Ren <guoren@kernel.org>, Steven Rostedt <rostedt@goodmis.org>,
	Ingo Molnar <mingo@redhat.com>,
	"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
	Helge Deller <deller@gmx.de>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Jiri Kosina <jikos@kernel.org>, Miroslav Benes <mbenes@suse.cz>,
	Petr Mladek <pmladek@suse.com>,
	Joe Lawrence <joe.lawrence@redhat.com>,
	Colin Ian King <colin.king@canonical.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Nicholas Piggin <npiggin@gmail.com>,
	Jisheng Zhang <jszhang@kernel.org>,
	linux-csky@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-riscv@lists.infradead.org, live-patching@vger.kernel.org
Subject: [RESEND PATCH v2 0/2] fix & prevent the missing preemption disabling
Date: Wed, 13 Oct 2021 11:37:06 +0800	[thread overview]
Message-ID: <b1d7fe43-ce84-0ed7-32f7-ea1d12d0b716@linux.alibaba.com> (raw)

The testing show that perf_ftrace_function_call() are using smp_processor_id()
with preemption enabled, all the checking on CPU could be wrong after preemption.

As Peter point out, the section between ftrace_test_recursion_trylock/unlock()
pair require the preemption to be disabled as 'Documentation/trace/ftrace-uses.rst'
explained, but currently the work is done outside of the helpers.

Patch 1/2 will make sure preemption disabled after trylock() succeed,
patch 2/2 will do smp_processor_id() checking after trylock to address the
issue.

v1: https://lore.kernel.org/all/8c7de46d-9869-aa5e-2bb9-5dbc2eda395e@linux.alibaba.com/

Michael Wang (2):
  ftrace: disable preemption between ftrace_test_recursion_trylock/unlock()
  ftrace: do CPU checking after preemption disabled

 arch/csky/kernel/probes/ftrace.c     |  2 --
 arch/parisc/kernel/ftrace.c          |  2 --
 arch/powerpc/kernel/kprobes-ftrace.c |  2 --
 arch/riscv/kernel/probes/ftrace.c    |  2 --
 arch/x86/kernel/kprobes/ftrace.c     |  2 --
 include/linux/trace_recursion.h      | 22 +++++++++++++++++++++-
 kernel/livepatch/patch.c             |  6 ------
 kernel/trace/trace_event_perf.c      |  6 +++---
 kernel/trace/trace_functions.c       |  5 -----
 9 files changed, 24 insertions(+), 25 deletions(-)

-- 
1.8.3.1


             reply	other threads:[~2021-10-13  3:37 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-13  3:37 王贇 [this message]
2021-10-13  3:37 ` [RESEND PATCH v2 1/2] ftrace: disable preemption between ftrace_test_recursion_trylock/unlock() 王贇
2021-10-13  7:55   ` Miroslav Benes
2021-10-13  8:11     ` 王贇
2021-10-13  8:25       ` Miroslav Benes
2021-10-13  8:34         ` 王贇
2021-10-13 14:24           ` Steven Rostedt
2021-10-13  3:38 ` [RESEND PATCH v2 2/2] ftrace: do CPU checking after preemption disabled 王贇

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