Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755630AbcJPDMH (ORCPT ); Sat, 15 Oct 2016 23:12:07 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:35667 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755215AbcJPDL7 (ORCPT ); Sat, 15 Oct 2016 23:11:59 -0400 Message-ID: <1476587514.1538.5.camel@gmail.com> Subject: [patch] drivers,connector: Protect send_msg() with a local lock for RT From: Mike Galbraith To: Sebastian Andrzej Siewior , Thomas Gleixner Cc: LKML , linux-rt-users , Steven Rostedt Date: Sun, 16 Oct 2016 05:11:54 +0200 In-Reply-To: <20161006085228.jl6rpszdp5c2p2nr@linutronix.de> References: <20161006085228.jl6rpszdp5c2p2nr@linutronix.de> Content-Type: text/plain; charset="us-ascii" X-Mailer: Evolution 3.16.5 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2847 Lines: 64 [ 6496.323071] BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:931 [ 6496.323072] in_atomic(): 1, irqs_disabled(): 0, pid: 31807, name: sleep [ 6496.323077] Preemption disabled at:[] proc_exit_connector+0xbb/0x140 [ 6496.323077] [ 6496.323080] CPU: 4 PID: 31807 Comm: sleep Tainted: G W E 4.8.0-rt11-rt #106 [ 6496.323081] Hardware name: IBM System x3550 M3 -[7944K3G]-/69Y5698 , BIOS -[D6E150AUS-1.10]- 12/15/2010 [ 6496.323084] 0000000000000000 ffff8801051d3d08 ffffffff813436cd 0000000000000000 [ 6496.323086] ffff880167ccab80 ffff8801051d3d28 ffffffff8109c425 ffffffff81ce91c0 [ 6496.323088] 0000000000000000 ffff8801051d3d40 ffffffff816406b0 ffffffff81ce91c0 [ 6496.323089] Call Trace: [ 6496.323092] [] dump_stack+0x65/0x88 [ 6496.323094] [] ___might_sleep+0xf5/0x180 [ 6496.323097] [] __rt_spin_lock+0x20/0x50 [ 6496.323100] [] rt_read_lock+0x28/0x30 [ 6496.323103] [] netlink_broadcast_filtered+0x49/0x3f0 [ 6496.323106] [] ? __kmalloc_reserve.isra.33+0x31/0x90 [ 6496.323109] [] netlink_broadcast+0x1d/0x20 [ 6496.323111] [] cn_netlink_send_mult+0x19a/0x1f0 [ 6496.323114] [] cn_netlink_send+0x1b/0x20 [ 6496.323116] [] proc_exit_connector+0xf8/0x140 [ 6496.323119] [] do_exit+0x5d1/0xba0 [ 6496.323122] [] do_group_exit+0x4c/0xc0 [ 6496.323125] [] SyS_exit_group+0x14/0x20 [ 6496.323127] [] entry_SYSCALL_64_fastpath+0x1a/0xa4 Signed-off-by: Mike Galbraith --- drivers/connector/cn_proc.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/drivers/connector/cn_proc.c +++ b/drivers/connector/cn_proc.c @@ -32,6 +32,7 @@ #include #include +#include /* * Size of a cn_msg followed by a proc_event structure. Since the @@ -54,10 +55,12 @@ static struct cb_id cn_proc_event_id = { /* proc_event_counts is used as the sequence number of the netlink message */ static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 }; +static DEFINE_LOCAL_IRQ_LOCK(send_msg_lock); static inline void send_msg(struct cn_msg *msg) { - preempt_disable(); + /* RT ordering protection, maps to preempt_disable() for !RT */ + local_lock(send_msg_lock); msg->seq = __this_cpu_inc_return(proc_event_counts) - 1; ((struct proc_event *)msg->data)->cpu = smp_processor_id(); @@ -70,7 +73,7 @@ static inline void send_msg(struct cn_ms */ cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_NOWAIT); - preempt_enable(); + local_unlock(send_msg_lock); } void proc_fork_connector(struct task_struct *task)