From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej2-f12.google.com (mail-ej2-f12.google.com [74.125.228.140]) (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 08E9827FB25 for ; Mon, 14 Sep 2026 18:28:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.228.140 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789410538; cv=none; b=KzAUM4FLdbVZszg5RZE/9CouMdGX2u51bIsdqagzNfO2VH8Hu+kXWYnTcPXfc3qK3MpbZkxx+/NmrX5tRB7cK5KRZq3xOBBt5kH2RBKFpzwPeaJMMagxMJ/S9ZZweubMokwGdusd3V4gjdSrXACyvybjssGpgNueBXbLmqjyboc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789410538; c=relaxed/simple; bh=Pwu/0Cot70c9cl/FQ0qDdWdGr0VR3q3j9hvKe2dSMUU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=nIaqX9qcp8/Jd1UCi8tggMvCrOK+98Z3LNpqg3JOYaRh0BSjclhqtPbqa8A9/xNKenPK6biWlyg09idqH/m5+j0d2rTdpDWfFt7bAeX6t6jlw6012rtVuMcScTmSKUJZncN1QOui2bKSXZis6l6Ee2C3gQQJUj2dn+dFVrPAN24= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=tIfOgnJy; arc=none smtp.client-ip=74.125.228.140 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="tIfOgnJy" Received: by mail-ej2-f12.google.com with SMTP id a640c23a62f3a-c294496989aso416438366b.3 for ; Mon, 14 Sep 2026 11:28:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1789410535; x=1790015335; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=TzAQVlxc3SiItgqPCAg4pRFm0RhGbGZG5JH2sIt5XL4=; b=tIfOgnJyAl/VbEUJeidi5elXy9sxivmH9fqWsr9PJtIClxDujdC6IYllYnY8dPG+3u NJ2U5ONAAcD+UFOMvbBlQMFCpTIwYxZ9/WKXlcCwoJGNssKfGmLCb7TJFv8gbFYx0uJ3 8lH0jVe87JkzHmxvUTWPAfBr6ryLvBi+6QsSgfWY9K6a3O1wAJXNE/NgJf+ZHoeD7/Pn E8ef59hAGUTDGF+v3XgbeudtLM+dVPsnDnz8pjR1OQvyiPWek7l9bDtoRsVaQ1NUuEFH Vwdyw14+1i3gfyVuOZRU6nPPDcpoFHh0FKgdTjegktLhCZrXlWkY3N5uibhR61CeI/tU gVNQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1789410535; x=1790015335; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=TzAQVlxc3SiItgqPCAg4pRFm0RhGbGZG5JH2sIt5XL4=; b=znSLvoL6Shke/oRYrFISeO/HyYjyRNPlEBDfb7oxwnlLlirEgE2vP5z/D0eRcBDLlc ZONsto/CVKm+V+Vpf+1vrvjVzm9otSJAH+5ynz3LVI0ttToZ1uvIinIY6qPblRUvxGJs uynWXAdqIXbzjJNLgAEokGhIPHzUjKqtV2R5rDx0F6pplhP8k2lD2hAVaXGV09AjUbmp WlsgfqQuN8F8IY0LASxvtfXGodsGnPJTKNnjyAiqyveT8KgeFQfXj4k585d7r1F/+d54 zTe92tL7qIh67cQ23nYl3RSVtv91r2zgc+QHHcwsASuKXJleBt2YuQjE+t971xUQ0Avv GWYg== X-Forwarded-Encrypted: i=1; AKwUvBwyLwJHZXT6y6i0z4KV9WAtTA4M/4fylsfHAHwrVHe9lSbbzR9hfis5McG0+cSfrd9JuMpcR7o=@vger.kernel.org X-Gm-Message-State: AFuF++lqnhLwqGmgVbMSDQg2wNam8ej2pK5Tu5zzauKOBg+/3xlwIosu oCCD72hQIiMr2Q8V38FiggzOJ/foSqS0Rbyzojx3Yo2tZTttMqWbenMs X-Gm-Gg: AYBFou3O6WRX30BsKOduj+otd8V6GF7KnK7nEK08hjkNtOt7mHYy0bYCVMsVGvy9J+V 67WMKnSbqWos3fEu//NzSuwnfy3lIhvgon3xHIDDwySofmE6mXaeFNuuFI7tDhMhie2jHUhvzYW Eeau9AsMGKLZA2I8+/VFe1ydYeDvBsZScpOOucGvUi1nBq6lWLq2pDv9YMZk24mDLvbcuOkp8Rk KQmyOzkyMublQwG0ywFwE50Eeb8J0fwMLt6gLtQsoSTpuj5awEoLdfDmgV4cZX2IP3Wzb2GdXHa E+2ABxMgGVRWl2yTKCCpbAYkN4KBqztoasrLAiJRi1+rhoeUJahM9qcXqhdyA6pBksBeAMShN5U s/PIdiGeUkQnyWHm5yc9uDA9WTxnw+S09TVbmVmzl4gxr/BNljVIKl/7ui8JPNR0P6HLIzsUWMR l6JjYGjcFNkuJkH84LxBtxtGK/W8buef1LE4A9gglYibHYbmHW9rAqUtQy7w0gcir5vd8Cs31Fm 07HJ5ERG/sgD3WqrWhYmQnvfjDIrX24Pi0wwbzduitElTp+vMKXJtRoFLY= X-Received: by 2002:a17:907:c13:b0:c26:1648:a06c with SMTP id a640c23a62f3a-c29b8770a38mr275145766b.39.1789410534761; Mon, 14 Sep 2026 11:28:54 -0700 (PDT) Received: from dohko.chello.ie (188-141-5-72.dynamic.upc.ie. [188.141.5.72]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c296614b29bsm467316666b.62.2026.09.14.11.28.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Sep 2026 11:28:54 -0700 (PDT) From: David Carlier To: rostedt@goodmis.org, mhiramat@kernel.org Cc: mathieu.desnoyers@efficios.com, vdonnefort@google.com, linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, David Carlier , stable@vger.kernel.org Subject: [PATCH] ring-buffer: Take cpus_read_lock() when changing the subbuf order Date: Mon, 14 Sep 2026 19:28:43 +0100 Message-ID: <20260914182850.21449-1-devnexen@gmail.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit A CPU coming online during ring_buffer_subbuf_order_set() can be added to buffer->cpumask after the allocation loop, and the install loop then uses its empty new_pages list, corrupting the buffer. Take cpus_read_lock() as ring_buffer_resize() does. Fixes: f9b94daa542a ("ring-buffer: Set new size of the ring buffer sub page") Cc: stable@vger.kernel.org Signed-off-by: David Carlier --- kernel/trace/ring_buffer.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 04bb94c29f58..445931bc9ae0 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -7464,6 +7464,12 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) if (psize > RB_WRITE_MASK + 1) return -EINVAL; + /* + * Keep CPUs from coming online while changing the order to + * synchronize with new per CPU buffers being created. + */ + guard(cpus_read_lock)(); + /* prevent another thread from changing buffer sizes */ guard(mutex)(&buffer->mutex); -- 2.55.0