From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-560692-1519835306-2-10998927333106496498 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.249, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='uk', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1519835306; b=FqW4aufIuQ9NvqVHKXBukZ7sfqdFm/KmTBXlpq8iOjUKb0m tMjR+3H5XAyMjGiZXF0JgBr52oIEOQGG6G8qpkIgSh51gFPG0bU5Vht/86AQmQ9r My+X/uENB/WidrRv5lwAcrtNdOU5qk4AZ+Epv+Va7tcTn6xz54lCnPvBYHU8SlF7 v906104XDnl/SwbUF/otxjMzpqAO3qZRnmHMYG0Ef1qPt8vZrBkGCujXlyoHgg7h ibtNQVt6Gb1759wSVjkllqwK9prjEVwHPPVsh7Css/dyuFKbrKlRYN2PxJ7a68zg b7dV7C2A6W8ehuget6ZvDAKMGMOPUi95KOjiNag== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-type:content-transfer-encoding :mime-version:from:to:cc:date:message-id:subject:in-reply-to :sender:list-id; s=arctest; t=1519835306; bh=zoL0afuUrC8dAF6hvoz Fo1ekGZyMEYIXdwP5cLM5zhc=; b=rXcZ7dp0NhqMz9cxCjUhelfVLG1zUgJ/CFl +ZZUloKYnI0x5AZxz29vHws+JQu2iiIegrMgbwnfV8eRgBEmxbidhQDAuXXNdT/o QkP4iOfwxdIq58KozqnF0nfMAepTho85x5jctCH9yMYM2xyP509BLo2Y4wXyxVXz +j1sLO2g6DqlAwUbNob0VdrX2CG/+ZK1YMaW1UlSlEtceVJNv4sloM14gtFHm+Eb 4SkCreI0hMau7QGffV8N4eN1cEH7cAwD2wNLQsHbSiCDTBW369oUXnO6bBFSvGnA ZgDruyAUS/RWiVmtDEX9+0iP3QhB+NAUNCccjwJUCu7x1PS+60Q== ARC-Authentication-Results: i=1; mx1.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=decadent.org.uk header.result=pass header_is_org_domain=yes Authentication-Results: mx1.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=decadent.org.uk header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934495AbeB1QPq (ORCPT ); Wed, 28 Feb 2018 11:15:46 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:35196 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934483AbeB1QPn (ORCPT ); Wed, 28 Feb 2018 11:15:43 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Chunyan Zhang" , "Jing Xia" , "Steven Rostedt (VMware)" Date: Wed, 28 Feb 2018 15:20:18 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 145/254] tracing: Fix crash when it fails to alloc ring buffer In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.16.55-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jing Xia commit 24f2aaf952ee0b59f31c3a18b8b36c9e3d3c2cf5 upstream. Double free of the ring buffer happens when it fails to alloc new ring buffer instance for max_buffer if TRACER_MAX_TRACE is configured. The root cause is that the pointer is not set to NULL after the buffer is freed in allocate_trace_buffers(), and the freeing of the ring buffer is invoked again later if the pointer is not equal to Null, as: instance_mkdir() |-allocate_trace_buffers() |-allocate_trace_buffer(tr, &tr->trace_buffer...) |-allocate_trace_buffer(tr, &tr->max_buffer...) // allocate fail(-ENOMEM),first free // and the buffer pointer is not set to null |-ring_buffer_free(tr->trace_buffer.buffer) // out_free_tr |-free_trace_buffers() |-free_trace_buffer(&tr->trace_buffer); //if trace_buffer is not null, free again |-ring_buffer_free(buf->buffer) |-rb_free_cpu_buffer(buffer->buffers[cpu]) // ring_buffer_per_cpu is null, and // crash in ring_buffer_per_cpu->pages Link: http://lkml.kernel.org/r/20171226071253.8968-1-chunyan.zhang@spreadtrum.com Fixes: 737223fbca3b1 ("tracing: Consolidate buffer allocation code") Signed-off-by: Jing Xia Signed-off-by: Chunyan Zhang Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Ben Hutchings --- kernel/trace/trace.c | 2 ++ 1 file changed, 2 insertions(+) --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6243,7 +6243,9 @@ static int allocate_trace_buffers(struct allocate_snapshot ? size : 1); if (WARN_ON(ret)) { ring_buffer_free(tr->trace_buffer.buffer); + tr->trace_buffer.buffer = NULL; free_percpu(tr->trace_buffer.data); + tr->trace_buffer.data = NULL; return -ENOMEM; } tr->allocated_snapshot = allocate_snapshot;