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From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Chen Zhongjin <chenzhongjin@huawei.com>
Cc: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>,
	mark.rutland@arm.com, broonie@kernel.org, ardb@kernel.org,
	nobuta.keiya@fujitsu.com, sjitindarsingh@gmail.com,
	catalin.marinas@arm.com, will@kernel.org, jmorris@namei.org,
	linux-arm-kernel@lists.infradead.org,
	live-patching@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v1 0/9] arm64: livepatch: Use DWARF Call Frame Information for frame pointer validation
Date: Fri, 15 Apr 2022 17:56:09 -0700	[thread overview]
Message-ID: <20220416005609.3znhltjlhpg475ff@treble> (raw)
In-Reply-To: <35c99466-9024-a7fd-9632-5d21b3e558f7@huawei.com>

On Tue, Apr 12, 2022 at 04:32:22PM +0800, Chen Zhongjin wrote:
> By the way, I was thinking about a corner case, because arm64 CALL
> instruction won't push LR onto stack atomically as x86. Before push LR, FP
> to save frame there still can be some instructions such as bti, paciasp. If
> an irq happens here, the stack frame is not constructed so the FP unwinder
> will omit this function and provides a wrong stack trace to livepatch.
> 
> It's just a guess and I have not built the test case. But I think it's a
> defect on arm64 that FP unwinder can't work properly on prologue and
> epilogue. Do you have any idea about this?

x86 has similar issues with frame pointers, if for example preemption or
page fault exception occurs in a leaf function, or in a function
prologue or epilogue, before or after the frame pointer setup.

This issue is solved by the "reliable" unwinder which detects
irqs/exceptions on the stack and reports the stack as unreliable.

-- 
Josh


  reply	other threads:[~2022-04-16  2:14 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <95691cae4f4504f33d0fc9075541b1e7deefe96f>
2022-01-17 14:55 ` [PATCH v13 00/11] arm64: Reorganize the unwinder and implement stack trace reliability checks madvenka
2022-01-17 14:55   ` [PATCH v13 01/11] arm64: Remove NULL task check from unwind_frame() madvenka
2022-01-17 14:55   ` [PATCH v13 02/11] arm64: Rename unwinder functions madvenka
2022-01-17 14:56   ` [PATCH v13 03/11] arm64: Rename stackframe to unwind_state madvenka
2022-01-17 14:56   ` [PATCH v13 04/11] arm64: Split unwind_init() madvenka
2022-02-02 18:44     ` Mark Brown
2022-02-03  0:26       ` Madhavan T. Venkataraman
2022-02-03  0:39         ` Madhavan T. Venkataraman
2022-02-03 11:29           ` Mark Brown
2022-02-15 13:07     ` Mark Rutland
2022-02-15 18:04       ` Madhavan T. Venkataraman
2022-01-17 14:56   ` [PATCH v13 05/11] arm64: Copy the task argument to unwind_state madvenka
2022-02-02 18:45     ` Mark Brown
2022-02-15 13:22     ` Mark Rutland
2022-02-22 16:53       ` Madhavan T. Venkataraman
2022-01-17 14:56   ` [PATCH v13 06/11] arm64: Use stack_trace_consume_fn and rename args to unwind() madvenka
2022-02-02 18:46     ` Mark Brown
2022-02-03  0:34       ` Madhavan T. Venkataraman
2022-02-03 11:30         ` Mark Brown
2022-02-03 14:45           ` Madhavan T. Venkataraman
2022-02-15 13:39     ` Mark Rutland
2022-02-15 18:12       ` Madhavan T. Venkataraman
2022-03-07 16:51       ` Madhavan T. Venkataraman
2022-03-07 17:01         ` Mark Brown
2022-03-08 22:00           ` Madhavan T. Venkataraman
2022-03-09 11:47             ` Mark Brown
2022-03-09 15:34               ` Madhavan T. Venkataraman
2022-03-10  8:33               ` Miroslav Benes
2022-03-10 12:36                 ` Madhavan T. Venkataraman
2022-03-16  3:43               ` Josh Poimboeuf
2022-04-08 14:44         ` Mark Rutland
2022-04-08 17:58           ` Mark Rutland
2022-04-10 17:42             ` Madhavan T. Venkataraman
2022-04-10 17:33           ` Madhavan T. Venkataraman
2022-04-10 17:45           ` Madhavan T. Venkataraman
2022-01-17 14:56   ` [PATCH v13 07/11] arm64: Make the unwind loop in unwind() similar to other architectures madvenka
2022-01-17 14:56   ` [PATCH v13 08/11] arm64: Introduce stack trace reliability checks in the unwinder madvenka
2022-01-17 14:56   ` [PATCH v13 09/11] arm64: Create a list of SYM_CODE functions, check return PC against list madvenka
2022-01-17 14:56   ` [PATCH v13 10/11] arm64: Introduce arch_stack_walk_reliable() madvenka
2022-01-17 14:56   ` [PATCH v13 11/11] arm64: Select HAVE_RELIABLE_STACKTRACE madvenka
2022-01-25  5:21     ` nobuta.keiya
2022-01-25 13:43       ` Madhavan T. Venkataraman
2022-01-26 10:20         ` nobuta.keiya
2022-01-26 17:14           ` Madhavan T. Venkataraman
2022-01-27  1:13             ` nobuta.keiya
2022-01-26 17:16       ` Mark Brown
2022-04-07 20:25 ` [RFC PATCH v1 0/9] arm64: livepatch: Use DWARF Call Frame Information for frame pointer validation madvenka
2022-04-07 20:25   ` [RFC PATCH v1 1/9] objtool: Parse DWARF Call Frame Information in object files madvenka
2022-04-07 20:25   ` [RFC PATCH v1 2/9] objtool: Generate DWARF rules and place them in a special section madvenka
2022-04-07 20:25   ` [RFC PATCH v1 3/9] dwarf: Build the kernel with DWARF information madvenka
2022-04-07 20:25   ` [RFC PATCH v1 4/9] dwarf: Implement DWARF rule processing in the kernel madvenka
2022-04-07 20:25   ` [RFC PATCH v1 5/9] dwarf: Implement DWARF support for modules madvenka
2022-04-07 20:25   ` [RFC PATCH v1 6/9] arm64: unwinder: Add a reliability check in the unwinder based on DWARF CFI madvenka
2022-04-07 20:25   ` [RFC PATCH v1 7/9] arm64: dwarf: Implement unwind hints madvenka
2022-04-07 20:25   ` [RFC PATCH v1 8/9] dwarf: Miscellaneous changes required for enabling livepatch madvenka
2022-04-07 20:25   ` [RFC PATCH v1 9/9] dwarf: Enable livepatch for ARM64 madvenka
2022-04-08  0:21   ` [RFC PATCH v1 0/9] arm64: livepatch: Use DWARF Call Frame Information for frame pointer validation Josh Poimboeuf
2022-04-08 11:41     ` Peter Zijlstra
2022-04-11 17:26       ` Madhavan T. Venkataraman
2022-04-11 17:18     ` Madhavan T. Venkataraman
2022-04-12  8:32       ` Chen Zhongjin
2022-04-16  0:56         ` Josh Poimboeuf [this message]
2022-04-18 12:28           ` Chen Zhongjin
2022-04-18 16:11             ` Josh Poimboeuf
2022-04-18 18:38               ` Madhavan T. Venkataraman
     [not found]       ` <844b3ede-eddb-cbe6-80e0-3529e2da2eb6@huawei.com>
2022-04-12 17:27         ` Madhavan T. Venkataraman
2022-04-16  1:07       ` Josh Poimboeuf
2022-04-14 14:11     ` Madhavan T. Venkataraman
2022-04-08 10:55   ` Peter Zijlstra
2022-04-08 11:54     ` Peter Zijlstra
2022-04-08 14:34       ` Josh Poimboeuf
2022-04-10 17:47     ` Madhavan T. Venkataraman
2022-04-11 16:34       ` Josh Poimboeuf
2022-04-08 12:06   ` Peter Zijlstra
2022-04-11 17:35     ` Madhavan T. Venkataraman

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