From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mojiong Qiu Subject: [PATCH] xen/events: xen/events: fix RCU warning Date: Tue, 6 Nov 2012 16:08:15 +0800 Message-ID: <1352189295-7111-1-git-send-email-qiumojiong@gmail.com> Return-path: Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: Mojiong Qiu , Mojiong Qiu , Konrad Rzeszutek Wilk , Jeremy Fitzhardinge , xen-devel@lists.xensource.com, virtualization@lists.linux-foundation.org, "at least to 3.0.y" List-Id: xen-devel@lists.xenproject.org exit_idle() should be called after irq_enter(), otherwise it throws: [ 2.513020] [ INFO: suspicious RCU usage. ] [ 2.513076] 3.6.5 #1 Not tainted [ 2.513128] ------------------------------- [ 2.513183] include/linux/rcupdate.h:725 rcu_read_lock() used illegally while idle! [ 2.513271] [ 2.513271] other info that might help us debug this: [ 2.513271] [ 2.513388] [ 2.513388] RCU used illegally from idle CPU! [ 2.513388] rcu_scheduler_active = 1, debug_locks = 1 [ 2.513511] RCU used illegally from extended quiescent state! [ 2.513572] 1 lock held by swapper/0/0: [ 2.513626] #0: (rcu_read_lock){......}, at: [] __atomic_notifier_call_chain+0x0/0x140 [ 2.513815] [ 2.513815] stack backtrace: [ 2.513897] Pid: 0, comm: swapper/0 Not tainted 3.6.5 #1 [ 2.513954] Call Trace: [ 2.514005] [] lockdep_rcu_suspicious+0xe2/0x130 [ 2.514107] [] __atomic_notifier_call_chain+0x12c/0x140 [ 2.514169] [] ? atomic_notifier_chain_unregister+0x90/0x90 [ 2.514258] [] ? trace_hardirqs_off+0xd/0x10 [ 2.514318] [] atomic_notifier_call_chain+0x16/0x20 [ 2.514381] [] exit_idle+0x43/0x50 [ 2.514441] [] xen_evtchn_do_upcall+0x25/0x50 [ 2.514503] [] xen_do_hypervisor_callback+0x1e/0x30 [ 2.514562] [] ? hypercall_page+0x3aa/0x1000 [ 2.514662] [] ? hypercall_page+0x3aa/0x1000 [ 2.514722] [] ? xen_safe_halt+0x10/0x20 [ 2.514782] [] ? default_idle+0xba/0x570 [ 2.514841] [] ? cpu_idle+0xdf/0x140 [ 2.514900] [] ? rest_init+0x135/0x144 [ 2.514960] [] ? csum_partial_copy_generic+0x16c/0x16c [ 2.515022] [] ? start_kernel+0x3db/0x3e8 [ 2.515081] [] ? repair_env_string+0x5a/0x5a [ 2.515141] [] ? x86_64_start_reservations+0x131/0x135 [ 2.515202] [] ? xen_start_kernel+0x465/0x46 Signed-off-by: Mojiong Qiu Cc: Konrad Rzeszutek Wilk Cc: Jeremy Fitzhardinge Cc: xen-devel@lists.xensource.com Cc: virtualization@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org Cc: stable@kernel.org (at least to 3.0.y) --- drivers/xen/events.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/drivers/xen/events.c b/drivers/xen/events.c index 912ac81..0be4df3 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -1395,10 +1395,10 @@ void xen_evtchn_do_upcall(struct pt_regs *regs) { struct pt_regs *old_regs = set_irq_regs(regs); + irq_enter(); #ifdef CONFIG_X86 exit_idle(); #endif - irq_enter(); __xen_evtchn_do_upcall(); -- 1.6.3.2