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[2620:137:e000::3:7]) by mx.google.com with ESMTPS id y186-20020a6364c3000000b005c6818b5a24si3959702pgb.245.2023.12.09.20.04.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 09 Dec 2023 20:04:46 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:7 as permitted sender) client-ip=2620:137:e000::3:7; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:7 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by snail.vger.email (Postfix) with ESMTP id D356F809848A; Sat, 9 Dec 2023 20:04:44 -0800 (PST) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.11 at snail.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231608AbjLJEEc (ORCPT + 99 others); Sat, 9 Dec 2023 23:04:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33224 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231492AbjLJEEH (ORCPT ); Sat, 9 Dec 2023 23:04:07 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 229DA12E for ; Sat, 9 Dec 2023 20:04:14 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BBF91C433CB; Sun, 10 Dec 2023 04:04:13 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.97) (envelope-from ) id 1rCB3i-000000021PH-3FLz; Sat, 09 Dec 2023 23:04:50 -0500 Message-ID: <20231210040450.561181051@goodmis.org> User-Agent: quilt/0.67 Date: Sat, 09 Dec 2023 22:54:12 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Tzvetomir Stoyanov , Vincent Donnefort , Kent Overstreet Subject: [PATCH 08/14] ring-buffer: Make sure the spare sub buffer used for reads has same size References: <20231210035404.053677508@goodmis.org> MIME-Version: 1.0 X-Spam-Status: No, score=-1.7 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE, SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (snail.vger.email [0.0.0.0]); Sat, 09 Dec 2023 20:04:45 -0800 (PST) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1784866234147142747 X-GMAIL-MSGID: 1784866234147142747 From: "Steven Rostedt (Google)" Now that the ring buffer specifies the size of its sub buffers, they all need to be the same size. When doing a read, a swap is done with a spare page. Make sure they are the same size before doing the swap, otherwise the read will fail. Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 8e9853d38c8d..b3b36d7f1201 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -7567,6 +7567,7 @@ struct ftrace_buffer_info { struct trace_iterator iter; void *spare; unsigned int spare_cpu; + unsigned int spare_size; unsigned int read; }; @@ -8286,6 +8287,15 @@ tracing_buffers_read(struct file *filp, char __user *ubuf, page_size = ring_buffer_subbuf_size_get(iter->array_buffer->buffer); + /* Make sure the spare matches the current sub buffer size */ + if (info->spare) { + if (page_size != info->spare_size) { + ring_buffer_free_read_page(iter->array_buffer->buffer, + info->spare_cpu, info->spare); + info->spare = NULL; + } + } + if (!info->spare) { info->spare = ring_buffer_alloc_read_page(iter->array_buffer->buffer, iter->cpu_file); @@ -8294,6 +8304,7 @@ tracing_buffers_read(struct file *filp, char __user *ubuf, info->spare = NULL; } else { info->spare_cpu = iter->cpu_file; + info->spare_size = page_size; } } if (!info->spare)