From: Mark Brown <broonie@kernel.org>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Miroslav Benes <mbenes@suse.cz>, Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org, jpoimboe@redhat.com
Subject: Re: [RFC PATCH 0/3] arm64: Implement reliable stack trace
Date: Thu, 15 Oct 2020 16:49:51 +0100 [thread overview]
Message-ID: <20201015154951.GD4390@sirena.org.uk> (raw)
In-Reply-To: <20201015141612.GC50416@C02TD0UTHF1T.local>
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On Thu, Oct 15, 2020 at 03:16:12PM +0100, Mark Rutland wrote:
> On Thu, Oct 15, 2020 at 03:39:37PM +0200, Miroslav Benes wrote:
> > I'll just copy an excerpt from my notes about the required guarantees.
> > Written by Josh (CCed, he has better idea about the problem than me
> > anyway).
> > It also needs to:
> > - detect preemption / page fault frames and return an error
> > - only return success if it reaches the end of the task stack; for user
> > tasks, that means the syscall barrier; for kthreads/idle tasks, that
> > means finding a defined thread entry point
> > - make sure it can't get into a recursive loop
> > - make sure each return address is a valid text address
> > - properly detect generated code hacks like function graph tracing and
> > kretprobes
> > "
> It would be great if we could put something like the above into the
> kernel tree, either under Documentation/ or in a comment somewhere for
> the reliable stacktrace functions.
Yes, please - the expecations are quite hard to follow at the minute,
implementing it involves quite a bit of guesswork and cargo culting to
figure out what the APIs are supposed to do.
> AFAICT, existing architectures don't always handle all of the above in
> arch_stack_walk_reliable(). For example, it looks like x86 assumes
> unwiding through exceptions is reliable for !CONFIG_FRAME_POINTER, but I
> think this might not always be true.
I certainly wouldn't have inferred the list from what's there :/ The
searching for a defined thread entry point for example isn't entirely
visible in the implementations.
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next prev parent reply other threads:[~2020-10-15 15:51 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-12 17:26 [RFC PATCH 0/3] arm64: Implement reliable stack trace Mark Brown
2020-10-12 17:26 ` [RFC PATCH 1/3] arm64: remove EL0 exception frame record Mark Brown
2020-10-12 17:26 ` [RFC PATCH 2/3] arm64: stacktrace: Report when we reach the end of the stack Mark Brown
2020-10-13 11:07 ` Mark Rutland
2020-10-12 17:26 ` [RFC PATCH 3/3] arm64: stacktrace: Implement reliable stacktrace Mark Brown
2020-10-13 10:42 ` Mark Brown
2020-10-13 11:42 ` Mark Rutland
2020-10-13 16:12 ` Mark Brown
2020-10-15 13:33 ` Miroslav Benes
2020-10-15 15:57 ` Mark Brown
2020-10-16 10:13 ` Miroslav Benes
2020-10-16 12:30 ` Mark Brown
2020-10-15 13:39 ` [RFC PATCH 0/3] arm64: Implement reliable stack trace Miroslav Benes
2020-10-15 14:16 ` Mark Rutland
2020-10-15 15:49 ` Mark Brown [this message]
2020-10-15 21:29 ` Josh Poimboeuf
2020-10-15 21:29 ` Josh Poimboeuf
2020-10-16 11:14 ` Mark Rutland
2020-10-16 11:14 ` Mark Rutland
2020-10-20 10:03 ` Mark Rutland
2020-10-20 10:03 ` Mark Rutland
2020-10-20 15:58 ` Josh Poimboeuf
2020-10-20 15:58 ` Josh Poimboeuf
2020-10-16 12:15 ` Mark Brown
2020-10-16 12:15 ` Mark Brown
2020-10-19 23:41 ` Josh Poimboeuf
2020-10-19 23:41 ` Josh Poimboeuf
2020-10-20 15:39 ` Mark Brown
2020-10-20 15:39 ` Mark Brown
2020-10-20 16:28 ` Josh Poimboeuf
2020-10-20 16:28 ` Josh Poimboeuf
2021-01-27 14:02 ` Madhavan T. Venkataraman
2021-01-27 16:40 ` Mark Rutland
2021-01-27 17:11 ` Mark Brown
2021-01-27 17:24 ` Madhavan T. Venkataraman
2021-01-27 19:54 ` Madhavan T. Venkataraman
2021-01-28 14:22 ` Mark Brown
2021-01-28 15:26 ` Josh Poimboeuf
2021-01-29 21:39 ` Madhavan T. Venkataraman
2021-02-01 3:20 ` Madhavan T. Venkataraman
2021-02-01 14:39 ` Mark Brown
2021-01-30 4:38 ` Madhavan T. Venkataraman
2021-02-01 15:21 ` Madhavan T. Venkataraman
2021-02-01 15:46 ` Madhavan T. Venkataraman
2021-02-01 16:02 ` Mark Rutland
2021-02-01 16:22 ` Mark Brown
2021-02-01 21:40 ` Madhavan T. Venkataraman
2021-02-01 21:38 ` Madhavan T. Venkataraman
2021-02-01 23:00 ` Josh Poimboeuf
2021-02-02 2:29 ` Madhavan T. Venkataraman
2021-02-02 3:36 ` Josh Poimboeuf
2021-02-02 10:05 ` Mark Rutland
2021-02-02 13:33 ` Madhavan T. Venkataraman
2021-02-02 13:35 ` Madhavan T. Venkataraman
2021-02-02 23:32 ` Madhavan T. Venkataraman
2021-02-03 16:53 ` Mark Rutland
2021-02-03 19:03 ` Madhavan T. Venkataraman
2021-02-05 2:36 ` Madhavan T. Venkataraman
2021-02-01 21:59 ` Madhavan T. Venkataraman
2021-02-02 13:36 ` Mark Brown
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