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Tue, 20 Jun 2023 03:57:52 -0700 (PDT) MIME-Version: 1.0 References: <20230614095158.1133673-1-elver@google.com> In-Reply-To: <20230614095158.1133673-1-elver@google.com> From: Andrey Konovalov Date: Tue, 20 Jun 2023 12:57:39 +0200 Message-ID: Subject: Re: [PATCH] kasan: add support for kasan.fault=panic_on_write To: Marco Elver Cc: Andrew Morton , Alexander Potapenko , Dmitry Vyukov , Taras Madan , Aleksandr Nogikh , Andrey Ryabinin , Vincenzo Frascino , Jonathan Corbet , kasan-dev@googlegroups.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 518702000B X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: yk8kwfs4afpjb5ypz6ewa71psfdkefad X-HE-Tag: 1687258673-43766 X-HE-Meta: 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 1PWt8/d2 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 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 Wed, Jun 14, 2023 at 11:52=E2=80=AFAM Marco Elver wro= te: > > @@ -597,7 +614,11 @@ void kasan_report_async(void) > pr_err("Asynchronous fault: no details available\n"); > pr_err("\n"); > dump_stack_lvl(KERN_ERR); > - end_report(&flags, NULL); > + /* > + * Conservatively set is_write=3Dtrue, because no details are ava= ilable. > + * In this mode, kasan.fault=3Dpanic_on_write is like kasan.fault= =3Dpanic. > + */ > + end_report(&flags, NULL, true); Hi Marco, When asymm mode is enabled, kasan_report_async should only be called for read accesses. I think we could check the mode and panic accordingly. Please also update the documentation to describe the flag behavior wrt async/asymm modes. On a related note, it looks like we have a typo in KASAN documentation: it states that asymm mode detects reads synchronously, and writes - asynchronously. Should be the reverse. Thanks!