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References: <cover.1648049113.git.andreyknvl@google.com> <CANpmjNP_bWMzSkW=Q8Lc7yRWw8as_FoBpD-zwcweAiSBVn-Fsw@mail.gmail.com>
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From:   Andrey Konovalov <andreyknvl@gmail.com>
Date:   Tue, 29 Mar 2022 20:36:29 +0200
Message-ID: <CA+fCnZeiR4v72P1fbF1AP=RqViCnkdtES0NtcmN6-R-_9NS4kQ@mail.gmail.com>
Subject: Re: [PATCH v2 0/4] kasan, arm64, scs, stacktrace: collect stack
 traces from Shadow Call Stack
To:     Marco Elver <elver@google.com>
Cc:     andrey.konovalov@linux.dev,
        Alexander Potapenko <glider@google.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Sami Tolvanen <samitolvanen@google.com>,
        Peter Collingbourne <pcc@google.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Florian Mayer <fmayer@google.com>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Andrey Konovalov <andreyknvl@google.com>
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On Mon, Mar 28, 2022 at 2:36 PM Marco Elver <elver@google.com> wrote:
>
> > Changes v1->v2:
> > - Provide a kernel-wide stack_trace_save_shadow() interface for collecting
> >   stack traces from shadow stack.
> > - Use ptrauth_strip_insn_pac() and READ_ONCE_NOCHECK, see the comments.
> > - Get SCS pointer from x18, as per-task value is meant to save the SCS
> >   value on CPU switches.
> > - Collect stack frames from SDEI and IRQ contexts.
>
> Do any of these new changes introduce new (noticeable) overhead (in
> particular patch 2)?

I'll measure the overheads and include the results into v3. Thanks!