From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=193.142.43.55 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794571671; b=NcwQE6HclcK16wpWC1U93MhfOUyol2CGrqrET1P780HdNSNvRrH2XElaHPICg1PfEutr x4sEe8jITL9Rjc5J07xQm88TACFBmHjV7btkZXarx3FqQYI8VR56kkdvYoNa42+IZ7u11 HfGLfa1J45MV3q/Qb0z/v3nHvM+O/eg0EqIUXem2DIjccL2Cqk14mVpG6LXg7mHAFCHoj xXyyVIpQm6dWQZWxrERDu6s2qbKR40TVwlmfi70x6Pc+iEx233bJ5uO6/qN8lGB7EtJN1 fbpMeavhU40MLX3evVvxCAsZyHmnlS1i5HyMJPUf89l2+BQDG5SyQw6tMEA6fTo4NCQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794571671; h=DMARC-Filter:From:DKIM-Signature:DKIM-Signature:To:Cc:Subject: In-Reply-To:References:Date:Message-ID:MIME-Version:Content-Type; bh=zhfoN8norVHiHI9bD4jaoMKp9FFXhFPanvK9fbLLCgQ=; b=n7HEFRun/qzCoWJGV4i0nW+Yau4QssTjLVvPFRxvjGzJWkjD3CxgNpYGLexo37VbwiSD nM/wPOkYPZJI1q90HuYKwXn8JoZ15viTngmunpflmxNzR5Ai3LlSf59KXkIHSNYAubb0L s1ieD5HypwVjc+UJW9evWLz0OZTfCR2nb+CRjH+YYC0MvtYPSG2mH7RhWUMUw+Oer/dnw aT6HmKhjQKNomYpEaOA4cXC8/B6NG5lzBhYTDjx1jBdIzLwQ3Sl+318Lkl0yiL0A7pg+t AL3zWsc084Q06TgbxTT7wJO9c1fKIuRFMX5fJV22zLO9SotvWSvUfZt8e4hbTZYs8Pw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b="c/g3guVI"; dkim=pass header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=V0lO6HQJ; arc=none smtp.remote-ip=193.142.43.55 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B59D3606A8A6 for ; Fri, 13 Nov 2026 12:07:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org B59D3606A8A6 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b=c/g3guVI; dkim=pass header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=V0lO6HQJ From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1794571668; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=zhfoN8norVHiHI9bD4jaoMKp9FFXhFPanvK9fbLLCgQ=; b=c/g3guVInrZ62aChjGsNMm6JqaNL5J1eyxwZDMGrTRB/uJYOJePAg5LbcLhe4lVYp+IsX3 Kb7O82eVNIadsA4tHVXFryRE441Ug1MHi9ysQcUoSO84+5qmKfVw7rPDE39SUJ0A15Ce4y jw16R5sdtgH5NSb8k+gk6z3OQjthz5990prLRgpiMj7hlRHAV4QrIXN87yofITXQCSqO7u IgtJg482+4aeARircyUSxJu3Z6pQ6JFu4+6e5KhH2TC0AcLdHhHl7S3vZTN0/CNQLCW7Gf mfizeyMX4ago6ymjIXP3sTQGkBOubd8rZnILIT0VOCvS9nC2MYstabLE2LvB4g== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1794571668; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=zhfoN8norVHiHI9bD4jaoMKp9FFXhFPanvK9fbLLCgQ=; b=V0lO6HQJZ9EbUBg4kZ4FRlJOFSx4C7+0ZUjvbqNU81iZYzRm3DQjOqGeuUReizoVofefUE Cxyid5vnVS8VBlBQ== To: Zhu Jun , pmladek@suse.com Cc: rostedt@goodmis.org, senozhatsky@chromium.org, paulmck@kernel.org, printk@lists.linux.dev, linux-kernel@vger.kernel.org, zhujun2@cmss.chinamobile.com Subject: Re: [PATCH v3] printk: ringbuffer: Annotate speculative record reads In-Reply-To: <20261113075039.172176-1-zhujun2@cmss.chinamobile.com> References: <20261113075039.172176-1-zhujun2@cmss.chinamobile.com> Date: Fri, 13 Nov 2026 13:13:48 +0106 Message-ID: <87tsllvsrv.fsf@jogness.linutronix.de> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain On 2026-11-13, Zhu Jun wrote: > Readers may copy a finalized record while a writer recycles its storage. > prb_read() checks the descriptor again after copying and rejects records > that have changed, but the plain metadata and text accesses still trigger > KCSAN reports. > > Annotate the speculative copies, line counting and length read with > data_race(). The descriptor validation continues to determine whether > the copied record can be used. > > Fixes: b6cf8b3f3312 ("printk: add lockless ringbuffer") > Signed-off-by: Zhu Jun Reviewed-by: John Ogness Thanks!