Re: [RFC PATCH v2 3/4] arm64: Detect FTRACE cases that make the stack trace unreliable

From: Madhavan T. Venkataraman
Date: Thu Apr 08 2021 - 15:23:45 EST




On 4/8/21 11:58 AM, Mark Brown wrote:
> On Mon, Apr 05, 2021 at 03:43:12PM -0500, madvenka@xxxxxxxxxxxxxxxxxxx wrote:
>> From: "Madhavan T. Venkataraman" <madvenka@xxxxxxxxxxxxxxxxxxx>
>>
>> When CONFIG_DYNAMIC_FTRACE_WITH_REGS is enabled and tracing is activated
>> for a function, the ftrace infrastructure is called for the function at
>> the very beginning. Ftrace creates two frames:
>
> This looks good to me however I'd really like someone who has a firmer
> understanding of what ftrace is doing to double check as it is entirely
> likely that I am missing cases here, it seems likely that if I am
> missing stuff it's extra stuff that needs to be added and we're not
> actually making use of the reliability information yet.
>

OK. So, do you have some specific reviewer(s) in mind? Apart from yourself, Mark Rutland and
Josh Poimboeuf, these are some reviewers I can think of (in alphabetical order):

AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Catalin Marinas <catalin.marinas@xxxxxxx>
Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Torsten Duwe <duwe@xxxxxxx>
Will Deacon <will@xxxxxxxxxx>

Sorry if I missed out any of the other experts.

Thanks.

Madhavan