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AJvYcCXJ3ONqXlZZ2JPMuPACJDvQxt8j6ETzYEmXaNGzChvj84DmALk4oz9ZqXiBFchJM9SpT6qiDlfWUA==@kvack.org X-Gm-Message-State: AOJu0YzuIJ/GIZcb7PRvp1V0GjU6zY3sY0F78TeJrcifdfje9QxjhFSy gHPUJsDRAqKKEurRSK7Z4IVgCSqm67gW1i4t7iDhqwkDfBiSVsxaPXRc+hFZyaEpwkaWYgW0mav 7Ng== X-Google-Smtp-Source: AGHT+IGyq2ix4kSVUhNc102rzu/+pi5sWigmai5zeC1C+WvM8GfTqI/Oxr6AI/FM5MqgBjTC/NiJq7z9XA== X-Received: from wrbbs6.prod.google.com ([2002:a05:6000:706:b0:3ed:665b:ec9d]) (user=elver job=prod-delivery.src-stubby-dispatcher) by 2002:adf:ce0c:0:b0:3ee:10b1:17bb with SMTP id ffacd0b85a97d-3ee10b11893mr1782304f8f.61.1758204394951; Thu, 18 Sep 2025 07:06:34 -0700 (PDT) Date: Thu, 18 Sep 2025 15:59:36 +0200 In-Reply-To: <20250918140451.1289454-1-elver@google.com> Mime-Version: 1.0 References: <20250918140451.1289454-1-elver@google.com> X-Mailer: git-send-email 2.51.0.384.g4c02a37b29-goog Message-ID: <20250918140451.1289454-26-elver@google.com> Subject: [PATCH v3 25/35] compiler: Let data_race() imply disabled capability analysis From: Marco Elver To: elver@google.com, Peter Zijlstra , Boqun Feng , Ingo Molnar , Will Deacon Cc: "David S. Miller" , Luc Van Oostenryck , "Paul E. McKenney" , Alexander Potapenko , Arnd Bergmann , Bart Van Assche , Bill Wendling , Christoph Hellwig , Dmitry Vyukov , Eric Dumazet , Frederic Weisbecker , Greg Kroah-Hartman , Herbert Xu , Ian Rogers , Jann Horn , Joel Fernandes , Jonathan Corbet , Josh Triplett , Justin Stitt , Kees Cook , Kentaro Takeda , Lukas Bulwahn , Mark Rutland , Mathieu Desnoyers , Miguel Ojeda , Nathan Chancellor , Neeraj Upadhyay , Nick Desaulniers , Steven Rostedt , Tetsuo Handa , Thomas Gleixner , Thomas Graf , Uladzislau Rezki , Waiman Long , kasan-dev@googlegroups.com, linux-crypto@vger.kernel.org, linux-doc@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-security-module@vger.kernel.org, linux-sparse@vger.kernel.org, llvm@lists.linux.dev, rcu@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: 7prfrtai15a4ctturoc4y49538ndbhbe X-Rspam-User: X-Rspamd-Queue-Id: 687911C0004 X-Rspamd-Server: rspam04 X-HE-Tag: 1758204396-189756 X-HE-Meta: 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 tayFUuK2 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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: List-Subscribe: List-Unsubscribe: Many patterns that involve data-racy accesses often deliberately ignore normal synchronization rules to avoid taking a lock. If we have a lock-guarded variable on which we do a lock-less data-racy access, rather than having to write capability_unsafe(data_race(..)), simply make the data_race(..) macro imply capability-unsafety. The data_race() macro already denotes the intent that something subtly unsafe is about to happen, so it should be clear enough as-is. Signed-off-by: Marco Elver --- v2: * New patch. --- include/linux/compiler.h | 2 ++ lib/test_capability-analysis.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 64ff73c533e5..eee60adb3645 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -186,7 +186,9 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, #define data_race(expr) \ ({ \ __kcsan_disable_current(); \ + disable_capability_analysis(); \ __auto_type __v = (expr); \ + enable_capability_analysis(); \ __kcsan_enable_current(); \ __v; \ }) diff --git a/lib/test_capability-analysis.c b/lib/test_capability-analysis.c index 12fd9716f0a4..513ad28ed06c 100644 --- a/lib/test_capability-analysis.c +++ b/lib/test_capability-analysis.c @@ -92,6 +92,8 @@ static void __used test_raw_spinlock_trylock_extra(struct test_raw_spinlock_data { unsigned long flags; + data_race(d->counter++); /* no warning */ + if (raw_spin_trylock_irq(&d->lock)) { d->counter++; raw_spin_unlock_irq(&d->lock); -- 2.51.0.384.g4c02a37b29-goog