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Mon, 12 Jul 2021 09:44:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=qv3Vo5xsbAOEJgLGiYQjQnACJg9fyGkdPANxzyRJ0u0=; b=YxBBHmI3ihh3rUAZ/HpfxdYI/ND6OwEcRE87eHmz6vpJk0+eabbOKTLzjPAHhaPmZk w32aSCR6KLnikoJXR6BtzDh90JoGuS28RKqIIjENeZZmUYEJbwP8Mrqu2BnPsUkY6leN mlEGsZM2OSF1zTCti5cuAFklbPzZbbkIXnuCMAn4Inb/Yki03iwTSTwuisyOIqeAKTE7 QKASs/Hu4FEREVrYg4reYBvWwaJFvJVrj4KE8PiPEYUzXxveOwK7dY2fS5PtuTd6sNzp aA44ScWsNdRd6mTHuz1xxlWdPTrQHl8oxnscIvCCbhC8KmermcAzaNyALgsZ3A/HUTSi cg/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=qv3Vo5xsbAOEJgLGiYQjQnACJg9fyGkdPANxzyRJ0u0=; b=NU/V6k9TFCmcvaFNIpy94h/VtDIeYPfnkvZBHCmS40frmoNo5F+nWePnxG4xe2HN7S 7GKDlHmduCoj9PcB/KkGk/kC99c7o/nb3YgGmZnhOzRhJwnpUkO+xEmBNYosrth60J3M OhuNnNniumf7mDGL9q5RnqFU3Y5ZdFBnhbFb5hHap/o8dMgag3PFPTlKDAHKNwK7kL+e 1o636jjyBv6mo0/R3g5Ln93UcEBuE7t2gf9Ekm2is5Acq5q3DUk6RVrHL/NuQjuha28O YQ3Cn/tG8sYXOU/x08u01qv3H0OEUnkEWh2RzPaU7Xvev+2dit6h7VKc7ixVyM8EBS/3 OrEA== X-Gm-Message-State: AOAM531TK6rTUHJVjbdZc+WhzGijKRMDyg0IQCDwAdulEt3ry6RzXWFD D8O59pmVDcpXJWtglHqmNrUB+Q== X-Google-Smtp-Source: ABdhPJwK3VzhGWa3A0Cjl11xE5bb+9d9dgWz6yHyUkbAZ6XWnHp3BGzBwKSF+UhXsDpR3C0/w/Rt9g== X-Received: by 2002:a5d:530c:: with SMTP id e12mr28211287wrv.130.1626108251006; Mon, 12 Jul 2021 09:44:11 -0700 (PDT) Received: from elver.google.com ([2a00:79e0:15:13:30c:6a5f:a6ae:eba0]) by smtp.gmail.com with ESMTPSA id f2sm14920362wrq.69.2021.07.12.09.44.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Jul 2021 09:44:09 -0700 (PDT) Date: Mon, 12 Jul 2021 18:44:04 +0200 From: Marco Elver To: Woody Lin Cc: Andrey Ryabinin , Dmitry Vyukov , Alexander Potapenko , Andrey Konovalov , Jonathan Corbet , Andrew Morton , kasan-dev@googlegroups.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm/kasan: move kasan.fault to mm/kasan/report.c Message-ID: References: <20210712151618.1549371-1-woodylin@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210712151618.1549371-1-woodylin@google.com> User-Agent: Mutt/2.0.5 (2021-01-21) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=google.com header.s=20161025 header.b=YxBBHmI3; spf=pass (imf07.hostedemail.com: domain of elver@google.com designates 209.85.221.43 as permitted sender) smtp.mailfrom=elver@google.com; dmarc=pass (policy=reject) header.from=google.com X-Stat-Signature: 1tddo1ynraxm6nzut8c9mppr74977o55 X-Rspamd-Queue-Id: 5E5C110036BD X-Rspamd-Server: rspam01 X-HE-Tag: 1626108252-608077 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Jul 12, 2021 at 11:16PM +0800, 'Woody Lin' via kasan-dev wrote: > Move the boot parameter 'kasan.fault' from hw_tags.c to report.c, so it > can support all KASAN modes - generic, and both tag-based. > > Signed-off-by: Woody Lin > --- > Documentation/dev-tools/kasan.rst | 2 ++ > mm/kasan/hw_tags.c | 43 ------------------------------- > mm/kasan/report.c | 29 ++++++++++++++++++--- > 3 files changed, 28 insertions(+), 46 deletions(-) > > diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst > index 83ec4a556c19..ab8e27d45632 100644 > --- a/Documentation/dev-tools/kasan.rst > +++ b/Documentation/dev-tools/kasan.rst > @@ -203,6 +203,8 @@ boot parameters that allow disabling KASAN or controlling its features. > report or also panic the kernel (default: ``report``). The panic happens even > if ``kasan_multi_shot`` is enabled. > > + Note: The boot parameter 'kasan.fault' is supported by all KASAN modes. This documentation change seems hacked on. Could we change it like this: diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst index 83ec4a556c19..21dc03bc10a4 100644 --- a/Documentation/dev-tools/kasan.rst +++ b/Documentation/dev-tools/kasan.rst @@ -181,9 +181,16 @@ By default, KASAN prints a bug report only for the first invalid memory access. With ``kasan_multi_shot``, KASAN prints a report on every invalid access. This effectively disables ``panic_on_warn`` for KASAN reports. +Alternatively, independent of ``panic_on_warn`` the ``kasan.fault=`` boot +parameter can be used to control panic and reporting behaviour: + +- ``kasan.fault=report`` or ``=panic`` controls whether to only print a KASAN + report or also panic the kernel (default: ``report``). The panic happens even + if ``kasan_multi_shot`` is enabled. + Hardware tag-based KASAN mode (see the section about various modes below) is intended for use in production as a security mitigation. Therefore, it supports -boot parameters that allow disabling KASAN or controlling its features. +additional boot parameters that allow disabling KASAN or controlling features: - ``kasan=off`` or ``=on`` controls whether KASAN is enabled (default: ``on``). @@ -199,10 +206,6 @@ boot parameters that allow disabling KASAN or controlling its features. - ``kasan.stacktrace=off`` or ``=on`` disables or enables alloc and free stack traces collection (default: ``on``). -- ``kasan.fault=report`` or ``=panic`` controls whether to only print a KASAN - report or also panic the kernel (default: ``report``). The panic happens even - if ``kasan_multi_shot`` is enabled. - Implementation details ---------------------- [...] > -/* Whether to panic or print a report and disable tag checking on fault. */ > -bool kasan_flag_panic __ro_after_init; There's also an extern declaration in kasan.h, which should be removed. Thanks, -- Marco