Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 20 Jun 2023 19:17:35 +0200
From:   Marco Elver <elver@google.com>
To:     Andrey Konovalov <andreyknvl@gmail.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Taras Madan <tarasmadan@google.com>,
        Aleksandr Nogikh <nogikh@google.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Jonathan Corbet <corbet@lwn.net>, kasan-dev@googlegroups.com,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, Catalin Marinas <catalin.marinas@arm.com>
Subject: [PATCH] kasan, doc: note kasan.fault=panic_on_write behaviour for
 async modes
Message-ID: <ZJHfL6vavKUZ3Yd8@elver.google.com>
References: <20230614095158.1133673-1-elver@google.com>
 <CA+fCnZdy4TmMacvsPkoenCynUYsyKZ+kU1fx7cDpbh_6=cEPAQ@mail.gmail.com>
 <CANpmjNOSnVNy14xAVe6UHD0eHuMpxweg86+mYLQHpLM1k0H_cg@mail.gmail.com>
 <CA+fCnZccdLNqtxubVVtGPTOXcSoYfpM9CHk-nrYsZK7csC77Eg@mail.gmail.com>
 <ZJGSqdDQPs0sRQTb@elver.google.com>
 <CA+fCnZdZ0=kKN6hE_OF7jV_r_FjTh3FZtkGHBD57ZfqCXStKHg@mail.gmail.com>
 <ZJG8WiamZvEJJKUc@elver.google.com>
 <CA+fCnZdStZDyTGJfiW1uZVhhb-DraZmHnam0cdrB83-nnoottA@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CA+fCnZdStZDyTGJfiW1uZVhhb-DraZmHnam0cdrB83-nnoottA@mail.gmail.com>
User-Agent: Mutt/2.2.9 (2022-11-12)
Precedence: bulk

Note the behaviour of kasan.fault=panic_on_write for async modes, since
all asynchronous faults will result in panic (even if they are reads).

Fixes: 452c03fdbed0 ("kasan: add support for kasan.fault=panic_on_write")
Signed-off-by: Marco Elver <elver@google.com>
---
 Documentation/dev-tools/kasan.rst | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst
index 7f37a46af574..f4acf9c2e90f 100644
--- a/Documentation/dev-tools/kasan.rst
+++ b/Documentation/dev-tools/kasan.rst
@@ -110,7 +110,9 @@ parameter can be used to control panic and reporting behaviour:
 - ``kasan.fault=report``, ``=panic``, or ``=panic_on_write`` controls whether
   to only print a KASAN report, panic the kernel, or panic the kernel on
   invalid writes only (default: ``report``). The panic happens even if
-  ``kasan_multi_shot`` is enabled.
+  ``kasan_multi_shot`` is enabled. Note that when using asynchronous mode of
+  Hardware Tag-Based KASAN, ``kasan.fault=panic_on_write`` always panics on
+  asynchronously checked accesses (including reads).
 
 Software and Hardware Tag-Based KASAN modes (see the section about various
 modes below) support altering stack trace collection behavior:
-- 
2.41.0.185.g7c58973941-goog