From: Atish Patra <atishp@atishpatra.org>
To: Guo Ren <guoren@kernel.org>, Zong Li <zong.li@sifive.com>
Cc: me@packi.ch, Guo Ren <guoren@linux.alibaba.com>,
Alan Kao <alankao@andestech.com>,
Anup Patel <anup@brainfault.org>,
Palmer Dabbelt <palmerdabbelt@google.com>,
"linux-kernel@vger.kernel.org List"
<linux-kernel@vger.kernel.org>,
rostedt@goodmis.org, linux-csky@vger.kernel.org,
mhiramat@kernel.org, Paul Walmsley <paul.walmsley@sifive.com>,
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: Mon, 19 Oct 2020 11:54:24 -0700 [thread overview]
Message-ID: <CAOnJCU+oTRcJ2p8WQDX5P-EsOHmkn3kP9s54VQa+iw2wXDvzkg@mail.gmail.com> (raw)
In-Reply-To: <1602918377-23573-10-git-send-email-guoren@kernel.org>
On Sat, Oct 17, 2020 at 12:07 AM <guoren@kernel.org> wrote:
>
> From: Guo Ren <guoren@linux.alibaba.com>
>
> It will cause warning messages:
> echo function_graph > /sys/kernel/debug/tracing/current_tracer
> [ 47.691397] ------------[ cut here ]------------
> [ 47.692899] WARNING: CPU: 0 PID: 11 at arch/riscv/kernel/patch.c:63 patch_insn_write+0x182/0x19a
> [ 47.694483] Modules linked in:
> [ 47.695754] CPU: 0 PID: 11 Comm: migration/0 Not tainted 5.9.0-11367-g1054335 #132
> [ 47.698228] epc: ffffffe000204530 ra : ffffffe00020452c sp : ffffffe0023ffc20 gp : ffffffe0013e1fe0 tp : ffffffe0023e4e00 t0 : 0000000000000000
> [ 47.701872] t1 : 000000000000000e t2 : 000000000000001b s0 : ffffffe0023ffc70 s1 : ffffffe000206850 a0 : 0000000000000000 a1 : ffffffffffffffff
> [ 47.705550] a2 : 0000000000000000 a3 : ffffffe03af7c5e8 a4 : 0000000000000000 a5 : 0000000000000000 a6 : 0000000000000000 a7 : 00000000150b02d8
> [ 47.709159] s2 : 0000000000000008 s3 : 0000000000000858 s4 : ffffffe0023ffc98 s5 : 0000000000000850 s6 : 0000000000000003 s7 : 0000000000000002
> [ 47.714135] s8 : 0000000000000004 s9 : 0000000000000001 s10: 0000000000000001 s11: 0000000000000003 t3 : ffffffffffffe000 t4 : 0000000000d86254
> [ 47.716574] t5 : 0000000000000005 t6 : 0000000000040000status: 0000000000000100 badaddr: 0000000000000000 cause: 0000000000000003
> [ 47.720019] CPU: 0 PID: 11 Comm: migration/0 Not tainted 5.9.0-11367-g1054335 #132
> [ 47.722074] Call Trace:
> [ 47.722561] [<ffffffe000203c88>] walk_stackframe+0x0/0xc2
> [ 47.724608] [<ffffffe000b2020a>] show_stack+0x46/0x52
> [ 47.726246] [<ffffffe000b23c24>] dump_stack+0x90/0xb6
> [ 47.727672] [<ffffffe00020c9c4>] __warn+0x98/0xfa
> [ 47.729131] [<ffffffe0005f4be0>] report_bug+0xaa/0x11e
> [ 47.730624] [<ffffffe000203b74>] do_trap_break+0x96/0xfe
> [ 47.732448] [<ffffffe000201daa>] ret_from_exception+0x0/0x14
> [ 47.734341] [<ffffffe00020452c>] patch_insn_write+0x17e/0x19a
> [ 47.737235] irq event stamp: 39
> [ 47.738521] hardirqs last enabled at (39): [<ffffffe000201d0a>] _save_context+0xa2/0xe6
> [ 47.741055] hardirqs last disabled at (38): [<ffffffe0002c2404>] multi_cpu_stop+0x130/0x166
> [ 47.743551] softirqs last enabled at (0): [<ffffffe00020a4d2>] copy_process+0x430/0x1316
> [ 47.746031] softirqs last disabled at (0): [<0000000000000000>] 0x0
> [ 47.748617] ---[ end trace 88a1054faa6524ef ]---
>
> Because the path of stop_machine(__ftrace_modify_code)->
> ftrace_modify_all_code->...->patch_insn_write has no pair of
> lock&unlock text_mutex, so we shouldn't put assert here.
>
What platform are you testing ? We are seeing a crash while enabling
any of the tracers multiple times
on Qemu/HiFive Unleashed.
http://lists.infradead.org/pipermail/linux-riscv/2020-October/002354.html
As per the thread, Zong agreed to take a look into that.
@Zong Li : Do you have any update regarding the ftrace issue.
> Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> ---
> arch/riscv/kernel/patch.c | 7 -------
> 1 file changed, 7 deletions(-)
>
> diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c
> index 0b55287..2ee5063 100644
> --- a/arch/riscv/kernel/patch.c
> +++ b/arch/riscv/kernel/patch.c
> @@ -55,13 +55,6 @@ static int patch_insn_write(void *addr, const void *insn, size_t len)
> bool across_pages = (((uintptr_t) addr & ~PAGE_MASK) + len) > PAGE_SIZE;
> int ret;
>
> - /*
> - * Before reaching here, it was expected to lock the text_mutex
> - * already, so we don't need to give another lock here and could
> - * ensure that it was safe between each cores.
> - */
> - lockdep_assert_held(&text_mutex);
> -
> if (across_pages)
> patch_map(addr + len, FIX_TEXT_POKE1);
>
> --
> 2.7.4
>
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
--
Regards,
Atish
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next prev parent reply other threads:[~2020-10-19 18:54 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 [this message]
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
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