[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] xen/events: xen/events: fix RCU warning
On Tue, Nov 06, 2012 at 04:08:15PM +0800, Mojiong Qiu wrote: > exit_idle() should be called after irq_enter(), otherwise it throws: That seems odd - wouldn't "smp_x86_platform_ipi" also need the same treatment [edit: I was looking at 3.0 kernel code] ? Ah, this is caused by commit 98ad1cc14a5c4fd658f9d72c6ba5c86dfd3ce0d5 Author: Frederic Weisbecker <fweisbec@xxxxxxxxx> Date: Fri Oct 7 18:22:09 2011 +0200 x86: Call idle notifier after irq_enter() and it missed the xen-case which means that any kernel v3.3 and newer need this, but earlier do not. Thx. Will put in 3.7 tree. > > [ 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: [<ffffffff810e9fe0>] > __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] <IRQ> [<ffffffff811259a2>] lockdep_rcu_suspicious+0xe2/0x130 > [ 2.514107] [<ffffffff810ea10c>] __atomic_notifier_call_chain+0x12c/0x140 > [ 2.514169] [<ffffffff810e9fe0>] ? > atomic_notifier_chain_unregister+0x90/0x90 > [ 2.514258] [<ffffffff811216cd>] ? trace_hardirqs_off+0xd/0x10 > [ 2.514318] [<ffffffff810ea136>] atomic_notifier_call_chain+0x16/0x20 > [ 2.514381] [<ffffffff810777c3>] exit_idle+0x43/0x50 > [ 2.514441] [<ffffffff81568865>] xen_evtchn_do_upcall+0x25/0x50 > [ 2.514503] [<ffffffff81aa690e>] xen_do_hypervisor_callback+0x1e/0x30 > [ 2.514562] <EOI> [<ffffffff810013aa>] ? hypercall_page+0x3aa/0x1000 > [ 2.514662] [<ffffffff810013aa>] ? hypercall_page+0x3aa/0x1000 > [ 2.514722] [<ffffffff81061540>] ? xen_safe_halt+0x10/0x20 > [ 2.514782] [<ffffffff81075cfa>] ? default_idle+0xba/0x570 > [ 2.514841] [<ffffffff810778af>] ? cpu_idle+0xdf/0x140 > [ 2.514900] [<ffffffff81a4d881>] ? rest_init+0x135/0x144 > [ 2.514960] [<ffffffff81a4d74c>] ? csum_partial_copy_generic+0x16c/0x16c > [ 2.515022] [<ffffffff82520c45>] ? start_kernel+0x3db/0x3e8 > [ 2.515081] [<ffffffff8252066a>] ? repair_env_string+0x5a/0x5a > [ 2.515141] [<ffffffff82520356>] ? x86_64_start_reservations+0x131/0x135 > [ 2.515202] [<ffffffff82524aca>] ? xen_start_kernel+0x465/0x46 > > Signed-off-by: Mojiong Qiu <mjqiu@xxxxxxxxxxx> > Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> > Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx> > Cc: xen-devel@xxxxxxxxxxxxxxxxxxx > Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx > Cc: stable@xxxxxxxxxx (at least to 3.0.y) ^^^- vger.kernel.org You mean 3.3.x > --- > 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 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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