From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) (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 96CEB47D466 for ; Thu, 13 Aug 2026 13:11:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.71 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786626721; cv=none; b=H+GUEVirWViRvddyJhu7SePi9L8Q+DExKNJKXlLj6RbHaPl/ryaxA64jXQlXM1fA7GBshDKzlwHRK21ONPZ4rU2bha+dj3SnF1gXmznf8XWK4mUOrUJiGsjXP5aih+Sq5OuCEzoWdKrEZ5Mdzr93UOmoEF1lLeYmdu+8uRszNxA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786626721; c=relaxed/simple; bh=tujv8RbwhrzNmaNzcMSZ3HxX1V8/EjqjdRXAbYVULcE=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=K4IbF5nXr5DRHePDMPCdCuYF03NsL/SZ88I3PZ2tyvh/n/5B1BGDtihwhgUFLAOlQroD4Iv5nSWYO+QeS7cy4LKvGu5ihGAjgayAuC1ThlsJeX1AO4A/70KBZ+A4+sp1FYqyMwXCJOKQJlAIhqImEOBiEGi7kLDwj0BVKkewLnE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=fi0uHD1j; arc=none smtp.client-ip=209.85.128.71 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--vdonnefort.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="fi0uHD1j" Received: by mail-wm1-f71.google.com with SMTP id 5b1f17b1804b1-4955d314945so3646295e9.0 for ; Thu, 13 Aug 2026 06:11:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1786626718; x=1787231518; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=SwGJJ+A9z3NJgDEvUS+8UxqlJZhSVXFUJkzDSX5uv20=; b=fi0uHD1jzMz8ceNNeT0Ll8lUKzomGviB1cqowK0+s8iDYNPndAcyfdFrGUbV9gm24W CRwaeQU6nGh4TjPAruwcw+62VsZrbKZjhGBnvsBQpKjZCFKwDVezQ1cj1XCL+g7xuZ7i Axy5sYPB5NPepLOY5zHTfgZ8g3MLmqK5ZMoiLauVQFBoATs5bDa26RvAdNfoPnctaHXS YRh214zeo7mjqqbdkaBlGkwQNjrh7Gwh3zBGfmgzpsevIuASBolk0uPMpdByAc8F7YWB dZQwuvw7lheMsEd7TxBRsQhFwwx7ilHFq1s5KAX3UNfOq74A15i5S6BUco8yAvi5O684 bxIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786626718; x=1787231518; h=content-type: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:content-type; bh=SwGJJ+A9z3NJgDEvUS+8UxqlJZhSVXFUJkzDSX5uv20=; b=ixuYF5jNq1MYPAueq9WDivAj3qSTUMZ46oZMqIanwTmuzGKS4ipep+ovt91nSYH791 H13If2BxoiAg1uUgGZPq+YC6G8u7yAuAymj7hpFTXD71IJj+0ScQo8y5ONcCIdcx1U4I lFAAO/57QNABlIUp8yF5Kn37y3OcEpYY/LvoPiCqz+AZp/8FAUb74eMwxmGh3xUW3dS4 HcnwfhZg/r5ihgv/tQnq70/fqSYJfTHfYhA+HZFLSiKTxktfXUNh5r7bzjI670zsv3sG nEOz8U9Pvxxa4p78DJp5BlQTroMhxOLMg/2rre5MepStixbf/QcoH2+zEYzCiGTShIiY jxlg== X-Forwarded-Encrypted: i=1; AHgh+RqcHgROSALZe8G3X2E2WTOcRw1yJaACMat8v/EaXXVBFjdZMd0/bmORInFEA+HAG1XbcFglzEGuvsIhDeY=@vger.kernel.org X-Gm-Message-State: AOJu0YyxgH8KHnQi38mmSJ2VhBpkNSyMVOfUH/YpjGBuzBIiM6xSoLwV 4V3zLbXjAcEwyYsNd+Ch9elhwILwqQ+MFNMhXb6mPTK9XfbnMZJP6Xp/M1yjyXqX/I368725T6f nXAfyMVi/EM2uGTfdJr71mQ== X-Received: from wmrk17.prod.google.com ([2002:a05:600c:b51:b0:493:f79d:63cc]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:3506:b0:499:4892:d022 with SMTP id 5b1f17b1804b1-499821c5b19mr62829445e9.8.1786626717503; Thu, 13 Aug 2026 06:11:57 -0700 (PDT) Date: Thu, 13 Aug 2026 14:11:44 +0100 In-Reply-To: <20260813131152.3589632-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260813131152.3589632-1-vdonnefort@google.com> X-Mailer: git-send-email 2.55.0.691.gc56d675ccc-goog Message-ID: <20260813131152.3589632-3-vdonnefort@google.com> Subject: [PATCH v5 02/10] ring-buffer: Hold cpu_buffer::lock when resizing a subbuf From: Vincent Donnefort To: rostedt@goodmis.org, mhiramat@kernel.org, linux-trace-kernel@vger.kernel.org Cc: mathieu.desnoyers@efficios.com, kernel-team@android.com, linux-kernel@vger.kernel.org, Vincent Donnefort , Sashiko Content-Type: text/plain; charset="UTF-8" Because, ring_buffer_subbuf_order_set() can clear cpu_buffer->free_page, hold cpu_buffer->lock to prevent races with ring_buffer_alloc_read_page() and ring_buffer_free_read_page(). Fixes: 8e7b58c27b3c ("ring-buffer: Just update the subbuffers when changing their allocation order") Reported-by: Sashiko Signed-off-by: Vincent Donnefort diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index a3d28b2e2c94..ec4f5a0c93e8 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -7431,8 +7431,10 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) cpu_buffer->nr_pages = cpu_buffer->nr_pages_to_update; cpu_buffer->nr_pages_to_update = 0; + arch_spin_lock(&cpu_buffer->lock); old_free_data_page = cpu_buffer->free_page; cpu_buffer->free_page = NULL; + arch_spin_unlock(&cpu_buffer->lock); rb_head_page_activate(cpu_buffer); -- 2.55.0.691.gc56d675ccc-goog