Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933399AbdIXUnE (ORCPT ); Sun, 24 Sep 2017 16:43:04 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:60906 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933348AbdIXUnC (ORCPT ); Sun, 24 Sep 2017 16:43:02 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Steven Rostedt (VMware)" Subject: [PATCH 4.13 076/109] ftrace: Fix memleak when unregistering dynamic ops when tracing disabled Date: Sun, 24 Sep 2017 22:33:37 +0200 Message-Id: <20170924203356.151806155@linuxfoundation.org> X-Mailer: git-send-email 2.14.1 In-Reply-To: <20170924203353.104695385@linuxfoundation.org> References: <20170924203353.104695385@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2906 Lines: 75 4.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Steven Rostedt (VMware) commit edb096e00724f02db5f6ec7900f3bbd465c6c76f upstream. If function tracing is disabled by the user via the function-trace option or the proc sysctl file, and a ftrace_ops that was allocated on the heap is unregistered, then the shutdown code exits out without doing the proper clean up. This was found via kmemleak and running the ftrace selftests, as one of the tests unregisters with function tracing disabled. # cat kmemleak unreferenced object 0xffffffffa0020000 (size 4096): comm "swapper/0", pid 1, jiffies 4294668889 (age 569.209s) hex dump (first 32 bytes): 55 ff 74 24 10 55 48 89 e5 ff 74 24 18 55 48 89 U.t$.UH...t$.UH. e5 48 81 ec a8 00 00 00 48 89 44 24 50 48 89 4c .H......H.D$PH.L backtrace: [] kmemleak_vmalloc+0x85/0xf0 [] __vmalloc_node_range+0x281/0x3e0 [] module_alloc+0x4f/0x90 [] arch_ftrace_update_trampoline+0x160/0x420 [] ftrace_startup+0xe7/0x300 [] register_ftrace_function+0x72/0x90 [] trace_selftest_ops+0x204/0x397 [] trace_selftest_startup_function+0x394/0x624 [] run_tracer_selftest+0x15c/0x1d7 [] init_trace_selftests+0x75/0x192 [] do_one_initcall+0x90/0x1e2 [] kernel_init_freeable+0x350/0x3fe [] kernel_init+0x13/0x122 [] ret_from_fork+0x2a/0x40 [] 0xffffffffffffffff Fixes: 12cce594fa ("ftrace/x86: Allow !CONFIG_PREEMPT dynamic ops to use allocated trampolines") Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/ftrace.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2828,13 +2828,14 @@ static int ftrace_shutdown(struct ftrace if (!command || !ftrace_enabled) { /* - * If these are per_cpu ops, they still need their - * per_cpu field freed. Since, function tracing is + * If these are dynamic or per_cpu ops, they still + * need their data freed. Since, function tracing is * not currently active, we can just free them * without synchronizing all CPUs. */ - if (ops->flags & FTRACE_OPS_FL_PER_CPU) - per_cpu_ops_free(ops); + if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) + goto free_ops; + return 0; } @@ -2900,6 +2901,7 @@ static int ftrace_shutdown(struct ftrace if (IS_ENABLED(CONFIG_PREEMPT)) synchronize_rcu_tasks(); + free_ops: arch_ftrace_trampoline_free(ops); if (ops->flags & FTRACE_OPS_FL_PER_CPU)