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From: Guo Ren <guoren@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: "Atish Patra" <atishp@atishpatra.org>,
	"Zong Li" <zong.li@sifive.com>,
	"Palmer Dabbelt" <palmerdabbelt@google.com>,
	"Paul Walmsley" <paul.walmsley@sifive.com>,
	"Masami Hiramatsu" <mhiramat@kernel.org>,
	"Alan Kao" <alankao@andestech.com>,
	"Patrick Stählin" <me@packi.ch>,
	"Guo Ren" <guoren@linux.alibaba.com>,
	"Anup Patel" <anup@brainfault.org>,
	"linux-kernel@vger.kernel.org List"
	<linux-kernel@vger.kernel.org>,
	linux-csky@vger.kernel.org,
	"Greentime Hu" <greentime.hu@sifive.com>,
	linux-riscv <linux-riscv@lists.infradead.org>
Subject: Re: [PATCH v4 9/9] riscv: Fixup lockdep_assert_held(&text_mutex) in patch_insn_write
Date: Wed, 21 Oct 2020 16:27:02 +0800	[thread overview]
Message-ID: <CAJF2gTSpcNAzhic9KTSygtjSbyTerA3VLFb2ziFu6uSGxgAhfg@mail.gmail.com> (raw)
In-Reply-To: <20201020164121.32626e45@gandalf.local.home>

Why?

funca:
nop                   addi  sp,sp, -8
nop                   sd ra, 0(sp)
nop, nop           auipc ra, 0x?
nop, nop  ->      jalr -?(ra)
nop                   ld ra,0(sp)
nop                   addi sp,sp, 8

When CPU0 has only changed half of them, CPU1 call funca then CPU1 broken.

On Wed, Oct 21, 2020 at 4:41 AM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Tue, 20 Oct 2020 19:18:01 +0800
> Guo Ren <guoren@kernel.org> wrote:
>
> > > What platform are you testing ? We are seeing a crash while enabling
> > > any of the tracers multiple times
> > > on Qemu/HiFive Unleashed.
> > I use qemu for testing. I've changed dynamic ftrace mechanism from
> > mcount to -fpatchable-entry.
> >
> > The problem is made by the lockdep checking of text_mutex.
>
> If you are switching to "patchable-entry" you shouldn't need to use
> stop_machine for the updates. No?
>
> -- Steve



--
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/

      parent reply	other threads:[~2020-10-21  8:27 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-17  7:06 [PATCH v4 0/9] Add k/uprobe & fentry & error_injection supported guoren
2020-10-17  7:06 ` [PATCH v4 1/9] RISC-V: Implement ptrace regs and stack API guoren
2020-11-06  1:03   ` Palmer Dabbelt
2020-11-06  2:54     ` Guo Ren
2020-10-17  7:06 ` [PATCH v4 2/9] riscv: Fixup compile error BUILD_BUG_ON failed guoren
2020-10-17  7:06 ` [PATCH v4 3/9] riscv: Fixup wrong ftrace remove cflag guoren
2020-10-17  7:06 ` [PATCH v4 4/9] riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT guoren
2020-10-17  7:06 ` [PATCH v4 5/9] riscv: Add kprobes supported guoren
2020-11-06  1:02   ` Palmer Dabbelt
2020-11-06  2:56     ` Guo Ren
2020-10-17  7:06 ` [PATCH v4 6/9] riscv: Add KPROBES_ON_FTRACE supported guoren
2020-10-17  7:06 ` [PATCH v4 7/9] riscv: Add uprobes supported guoren
2020-10-17  7:06 ` [PATCH v4 8/9] riscv: Add support for function error injection guoren
2020-10-17  7:06 ` [PATCH v4 9/9] riscv: Fixup lockdep_assert_held(&text_mutex) in patch_insn_write guoren
2020-10-19  8:36   ` Masami Hiramatsu
2020-10-19 11:03     ` Guo Ren
2020-10-20 11:14     ` Guo Ren
2020-10-19 18:54   ` Atish Patra
2020-10-20 11:18     ` Guo Ren
2020-10-20 20:41       ` Steven Rostedt
2020-10-21  7:10         ` Zong Li
2020-10-21  8:27         ` Guo Ren [this message]

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