From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f73.google.com (mail-wr1-f73.google.com [209.85.221.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7BE6631691E for ; Thu, 18 Sep 2025 14:06:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758204399; cv=none; b=ll2VT+yBfm+lI1xSjdUp6M1H3cPyGl5PpbPO7OEUweiEGFyC3M/ixTa/HZYk+zojVu4io5RaijMZ61BtGWNJEMBbzIIbO5Y6urIlREkMuD+scCQga+7wSXXRokqcfBOOi52sx3MVRCDgQVv9huLA68ae1eHjcN6VLhGdFRkdFgE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758204399; c=relaxed/simple; bh=zoLiY2UcfrfuFf9/eJmfFwA3ddXeQm8aQATv6UNlqMA=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=ab8y16GQTPtJYJ5cfOwJJf/d0xTEhXOCnCYzCF9N0rCdhA+LmpiB84nKAvVVlZIEKQQV2ivfaHIm1i/XFq73CcBXgSE0Or/NCkXSrM+5pcBpzaCO7OfZqYC25y61sbXlXfSV5AIMaOJXfMCeEubeYw/EWKci3P5/xMl98Iqe7IA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--elver.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=Cv6dyUvT; arc=none smtp.client-ip=209.85.221.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--elver.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Cv6dyUvT" Received: by mail-wr1-f73.google.com with SMTP id ffacd0b85a97d-3ee10a24246so556921f8f.3 for ; Thu, 18 Sep 2025 07:06:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1758204395; x=1758809195; darn=lists.linux.dev; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=rgYM57a4+YilIGK6iKKshTwAf6EJSKpu76VpXrklnPU=; b=Cv6dyUvT2Sh5uq9bdPyuCnKFHjF6N1riXhrn/RMzfLRkedeA5wOU1LnkfOlh7UX8ui ULIBZ7wToJZe5tPSbq1SHrDlXslaO4CAqy8zWtHTbGdIGJiloBRiTz/TPSQHf/MFJZIt 1JHwpd8BduQrWR8+qLzpLUKuob01ru6mF60BdwZTEhpTfJHD0MTcgf/94s7OIvxqSTvO iDMvzna+EVRwrhxx1YMV/ng0995OBopVdySZOJAop8mUXj7MuvEBgUq7am01qFK/nZMV EBvU/PtlVweZVVa8eQw1cGE4hIJ/StcFJpiqoa0jUqDGUG5CuQPxR43bon9R32DLGtea cWvg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1758204395; x=1758809195; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=rgYM57a4+YilIGK6iKKshTwAf6EJSKpu76VpXrklnPU=; b=FpJ6QV2kDWA/Al50zqlJ0J9ntgO1skEvBj1r0dK/fKNH7OmzWbBVNOaQV+I6vHV1jO Ax7BG4Eepir9pvaQU5KjE3h/jySR0fd8wplIMxwPR5krCqmxdo+61U6kMal7PIXFDlc1 0VJQxwY3zi2KcW+IRwR8Ir7gNKWqwlyfxwccgkWurmDOssBFTGN+ESxFGm5CK/pRAw0m qjzfw48fXQOPKUcIYhLQFaOjyAXMLjYGW8s/tTuAj78rTkEph3gcvDA4wTSVB4bGg6sg ovSdAP+grC+goIJwK6lNdzmazI06HatGKNS39es1NApUQP7SpapfIsqmx69uqLATazAi jXRA== X-Forwarded-Encrypted: i=1; AJvYcCXLjXupbsgTePsMijBof5JsPHgrh58LMUjhXdeauhXOUcruey5J7EZKezyU9XLM1XUMPJ9v@lists.linux.dev X-Gm-Message-State: AOJu0YwRd7X00ViPlIJqyTAP6Kula3AIaJANfiJxxEjixJ2iOfJOp+K2 SL8AL3waM9IPD8XstgrL/G3ydyoKuL3wkzpTfQlsQML1xFGoSdpTRpi22VAOqNQHKAwLQFSCE5E Cig== 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> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: 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" 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