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From: 王贇 <yun.wang@linux.alibaba.com>
To: Dave Hansen <dave.hansen@intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
	<x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>,
	"open list:X86 MM" <linux-kernel@vger.kernel.org>,
	"open list:BPF (Safe dynamic programs and tools)" 
	<netdev@vger.kernel.org>,
	"open list:BPF (Safe dynamic programs and tools)" 
	<bpf@vger.kernel.org>
Subject: Re: [PATCH] perf: fix panic by disable ftrace on fault.c
Date: Wed, 15 Sep 2021 15:34:20 +0800	[thread overview]
Message-ID: <09d0190b-f2cc-9e64-4d3a-4eb0def22b7b@linux.alibaba.com> (raw)
In-Reply-To: <ac31b8c7-122e-3467-566b-54f053ca0ae2@linux.alibaba.com>



On 2021/9/15 下午3:22, 王贇 wrote:
> 
> 
> On 2021/9/15 上午11:27, Dave Hansen wrote:
>> On 9/14/21 6:56 PM, 王贇 wrote:
>>>>> [   44.134987][    C0]  ? __sanitizer_cov_trace_pc+0x7/0x60
>>>>> [   44.135005][    C0]  ? kcov_common_handle+0x30/0x30
>>>> Just turning off tracing for the page fault handler is papering over the
>>>> problem.  It'll just come back later with a slightly different form.
>>>>
>>> Cool~ please let me know when you have the proper approach.
>>
>> It's an entertaining issue, but I wasn't planning on fixing it myself.
>>
> 
> Do you have any suggestion on how should we fix the problem?
> 
> I'd like to help fix it, but sounds like all the known working approach
> are not acceptable...

Hi, Dave, Peter

What if we just increase the stack size when ftrace enabled?

Maybe like:

diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h
index a8d4ad85..bc2e0c1 100644
--- a/arch/x86/include/asm/page_64_types.h
+++ b/arch/x86/include/asm/page_64_types.h
@@ -12,10 +12,16 @@
 #define KASAN_STACK_ORDER 0
 #endif

+#ifdef CONFIG_FUNCTION_TRACER
+#define FTRACE_STACK_ORDER 1
+#else
+#define FTRACE_STACK_ORDER 0
+#endif
+
 #define THREAD_SIZE_ORDER      (2 + KASAN_STACK_ORDER)
 #define THREAD_SIZE  (PAGE_SIZE << THREAD_SIZE_ORDER)

-#define EXCEPTION_STACK_ORDER (0 + KASAN_STACK_ORDER)
+#define EXCEPTION_STACK_ORDER (0 + KASAN_STACK_ORDER + FTRACE_STACK_ORDER)
 #define EXCEPTION_STKSZ (PAGE_SIZE << EXCEPTION_STACK_ORDER)

 #define IRQ_STACK_ORDER (2 + KASAN_STACK_ORDER)

Just like kasan we give more stack space for ftrace, is this looks
acceptable to you?

Regards,
Michael Wang

> 
> Regards,
> Michael Wang
> 

  reply	other threads:[~2021-09-15  7:34 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-09  3:13 [RFC PATCH] perf: fix panic by mark recursion inside perf_log_throttle 王贇
2021-09-09  6:10 ` 王贇
2021-09-10 15:38 ` Peter Zijlstra
2021-09-13  3:00   ` 王贇
2021-09-13  3:21     ` 王贇
2021-09-13 10:24     ` Peter Zijlstra
2021-09-13 10:36       ` Peter Zijlstra
2021-09-14  2:02         ` 王贇
2021-09-14  1:58       ` 王贇
2021-09-14 10:28         ` Peter Zijlstra
2021-09-15  1:51           ` 王贇
2021-09-15 15:17             ` [PATCH] x86/dumpstack/64: Add guard pages to stack_info Peter Zijlstra
2021-09-16  3:34               ` 王贇
2021-09-16  3:47               ` 王贇
2021-09-16  8:00                 ` Peter Zijlstra
2021-09-16  8:03                   ` Peter Zijlstra
2021-09-16 10:02                     ` Peter Zijlstra
2021-09-17  2:15                       ` 王贇
2021-09-17  3:02                       ` 王贇
2021-09-17 10:21                         ` Peter Zijlstra
2021-09-17 16:40                           ` Peter Zijlstra
2021-09-18  2:30                             ` 王贇
2021-09-18  6:56                               ` Peter Zijlstra
2021-09-18  2:38                             ` 王贇
2021-09-13  3:30 ` [PATCH] perf: fix panic by disable ftrace on fault.c 王贇
2021-09-13 14:49   ` Dave Hansen
2021-09-14  1:52     ` 王贇
2021-09-14  3:02       ` 王贇
2021-09-14  7:23         ` 王贇
2021-09-14 16:16           ` Dave Hansen
2021-09-15  1:56             ` 王贇
2021-09-15  3:27               ` Dave Hansen
2021-09-15  7:22                 ` 王贇
2021-09-15  7:34                   ` 王贇 [this message]
2021-09-15 15:19                     ` [PATCH] x86: Increase exception stack sizes Peter Zijlstra
2021-09-16  3:42                       ` 王贇
2021-09-21  7:28                       ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2021-09-21 12:41                       ` tip-bot2 for Peter Zijlstra
2021-09-14  2:08     ` [PATCH] perf: fix panic by disable ftrace on fault.c 王贇

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