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authorMojiong Qiu2012-11-06 16:08:15 +0800
committerKonrad Rzeszutek Wilk2012-11-07 10:41:27 -0500
commit772aebcefeff310f80e32b874988af0076cb799d (patch)
tree5e3e899b8b67a7905813360dc82302907eb65783
parent6d877e6b85691e0b2b22e90aeb9b86c3dafcfc6b (diff)
xen/events: fix RCU warning, or Call idle notifier after irq_enter()
exit_idle() should be called after irq_enter(), otherwise it throws: [ INFO: suspicious RCU usage. ] 3.6.5 #1 Not tainted ------------------------------- include/linux/rcupdate.h:725 rcu_read_lock() used illegally while idle! other info that might help us debug this: RCU used illegally from idle CPU! rcu_scheduler_active = 1, debug_locks = 1 RCU used illegally from extended quiescent state! 1 lock held by swapper/0/0: #0: (rcu_read_lock){......}, at: [<ffffffff810e9fe0>] __atomic_notifier_call_chain+0x0/0x140 stack backtrace: Pid: 0, comm: swapper/0 Not tainted 3.6.5 #1 Call Trace: <IRQ> [<ffffffff811259a2>] lockdep_rcu_suspicious+0xe2/0x130 [<ffffffff810ea10c>] __atomic_notifier_call_chain+0x12c/0x140 [<ffffffff810e9fe0>] ? atomic_notifier_chain_unregister+0x90/0x90 [<ffffffff811216cd>] ? trace_hardirqs_off+0xd/0x10 [<ffffffff810ea136>] atomic_notifier_call_chain+0x16/0x20 [<ffffffff810777c3>] exit_idle+0x43/0x50 [<ffffffff81568865>] xen_evtchn_do_upcall+0x25/0x50 [<ffffffff81aa690e>] xen_do_hypervisor_callback+0x1e/0x30 <EOI> [<ffffffff810013aa>] ? hypercall_page+0x3aa/0x1000 [<ffffffff810013aa>] ? hypercall_page+0x3aa/0x1000 [<ffffffff81061540>] ? xen_safe_halt+0x10/0x20 [<ffffffff81075cfa>] ? default_idle+0xba/0x570 [<ffffffff810778af>] ? cpu_idle+0xdf/0x140 [<ffffffff81a4d881>] ? rest_init+0x135/0x144 [<ffffffff81a4d74c>] ? csum_partial_copy_generic+0x16c/0x16c [<ffffffff82520c45>] ? start_kernel+0x3db/0x3e8 [<ffffffff8252066a>] ? repair_env_string+0x5a/0x5a [<ffffffff82520356>] ? x86_64_start_reservations+0x131/0x135 [<ffffffff82524aca>] ? xen_start_kernel+0x465/0x46 Git commit 98ad1cc14a5c4fd658f9d72c6ba5c86dfd3ce0d5 Author: Frederic Weisbecker <fweisbec@gmail.com> Date: Fri Oct 7 18:22:09 2011 +0200 x86: Call idle notifier after irq_enter() did this, but it missed the Xen code. Signed-off-by: Mojiong Qiu <mjqiu@tencent.com> Cc: stable@vger.kernel.org # from 3.3 and newer. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
-rw-r--r--drivers/xen/events.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 912ac81b6dbf..0be4df39e953 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();