Hello, John,
Strange. I wonder where the other four call stacks are coming from.
Thanx, Paul
On Wed, May 12, 2010 at 08:26:01AM -0400, [email protected] wrote:
> Hi Paul:
>
> I'm running on a single Intel Core 2 Duo.
>
> JP
>
> -----Original Message-----
> From: Paul E. McKenney [mailto:[email protected]]
> Sent: Tuesday, May 11, 2010 6:11 PM
> To: Mathieu Desnoyers
> Cc: John P. Paul; [email protected];
> [email protected]
> Subject: Re: [ltt-dev] lttctl locks up with RT Linux
>
> On Tue, May 11, 2010 at 11:11:20AM -0400, Mathieu Desnoyers wrote:
> > * [email protected] ([email protected]) wrote:
> > > Thanks Mathieu. I'm going to have to look at this a bit more. This
> may
> > > have fixed one problem and cause another as "lttctl -C -w /tmp/trace
> > > trace1" does not return and I'm getting a stack dump in the messages
> > > file (see below). The last msg I see from that "lttctl -C" command
> is
> > > "lttctl: Creating trace". The "lttctl: Forking lttd" is not
> displayed.
> >
> > If you disable RCU stalls detection, does it work ?
> >
> > [Context for Paul: it's on a -RT kernel, with the LTTng patchset]
>
> Strange. It looks like everyone is idle.
>
> Or is it possible that some CPU is spinning in an NMI handler?
>
> You have six call traces -- are there six CPUs online?
>
> Thanx, Paul
>
> > Thanks,
> >
> > Mathieu
> >
> > >
> > > JP
> > >
> > > May 11 10:05:00 ans-ebb3 kernel: P5
> > > May 11 10:05:00 ans-ebb3 kernel: INFO: RCU detected CPU stalls: P5
> (detected by 0, t=10002 jiffies)
> > > May 11 10:05:00 ans-ebb3 kernel: sending NMI to all CPUs:
> > > May 11 10:05:00 ans-ebb3 kernel: NMI backtrace for cpu 1
> > > May 11 10:05:00 ans-ebb3 kernel: Modules linked in: battery sbshc
> ehci_hcd sbs scsi_dh ohci_hcd dm_multipath uhci_hcd scsi_mod dm_mirror
> sd_mod libata ahci dm_mod dm_log dm_region_hash tpm_bios tpm intel_agp
> iTCO_vendor_support i2c_core pcspkr tpm_tis iTCO_wdt i2c_i801 autofs4
> e1000e button serio_raw sg output video ac parport lp parport_pc ipv6
> nvidia(P) [last unloaded: nvidia]
> > > May 11 10:05:00 ans-ebb3 kernel:
> > > May 11 10:05:00 ans-ebb3 kernel: Pid: 0, comm: swapper Tainted: P
> 2.6.33.2-rt13.11.trace #10 PXT /To Be Filled By O.E.M.
> > > May 11 10:05:00 ans-ebb3 kernel: EIP: 0060:[<c062e4fa>] EFLAGS:
> 00000246 CPU: 1
> > > May 11 10:05:00 ans-ebb3 kernel: EIP is at poll_idle+0x1e/0x5c
> > > May 11 10:05:00 ans-ebb3 kernel: EAX: f74bc000 EBX: 6b655cfc ECX:
> 6b655cfc EDX: 000001a2
> > > May 11 10:05:00 ans-ebb3 kernel: ESI: 000001a2 EDI: 00000000 EBP:
> f74bcf84 ESP: f74bcf7c
> > > May 11 10:05:00 ans-ebb3 kernel: DS: 007b ES: 007b FS: 00d8 GS:
> 0000 SS: 0068 preempt:04010002
> > > May 11 10:05:00 ans-ebb3 kernel: Process swapper (pid: 0,
> ti=f74bc000 task=f74d90c0 task.ti=f74bc000)
> > > May 11 10:05:00 ans-ebb3 kernel: Stack:
> > > May 11 10:05:00 ans-ebb3 kernel: f765b02c f765b01c f74bcf94
> c062e7c9 00000001 c0877c90 f74bcfa4 c0401c0d
> > > May 11 10:05:00 ans-ebb3 kernel: <0> 00000001 00000000 f74bcfb0
> c06ca177 01020800 00000000 00000000 00000000
> > > May 11 10:05:00 ans-ebb3 kernel: <0> 00000000 00000000 00000000
> 00000000 00000000 00000000 00000000 000000d8
> > > May 11 10:05:00 ans-ebb3 kernel: Call Trace:
> > > May 11 10:05:00 ans-ebb3 kernel: [<c062e7c9>] ?
> cpuidle_idle_call+0x6c/0xdf
> > > May 11 10:05:00 ans-ebb3 kernel: [<c0401c0d>] ? cpu_idle+0x49/0x80
> > > May 11 10:05:00 ans-ebb3 kernel: [<c06ca177>] ?
> start_secondary+0x1b9/0x1be
> > > May 11 10:05:00 ans-ebb3 kernel: Code: ff ff ff 8d 65 f4 89 d8 5b 5e
> 5f 5d c3 55 89 e5 56 53 e8 7b 61 e2 ff 89 c3 89 d6 fb 89 e0 25 00 f0 ff
> ff eb 02 f3 90 f6 40 08 08 <74> f8 e8 60 61 e2 ff 29 d8 19 f2 e8 95 b6
> e0 ff b9 40 42 0f 00
> > > May 11 10:05:00 ans-ebb3 kernel: Call Trace:
> > > May 11 10:05:00 ans-ebb3 kernel: [<c062e7c9>]
> cpuidle_idle_call+0x6c/0xdf
> > > May 11 10:05:00 ans-ebb3 kernel: [<c0401c0d>] cpu_idle+0x49/0x80
> > > May 11 10:05:00 ans-ebb3 kernel: [<c06ca177>]
> start_secondary+0x1b9/0x1be
> > > May 11 10:05:00 ans-ebb3 kernel: Pid: 0, comm: swapper Tainted: P
> 2.6.33.2-rt13.11.trace #10
> > > May 11 10:05:00 ans-ebb3 kernel: Call Trace:
> > > May 11 10:05:00 ans-ebb3 kernel: [<c04019d4>] ? show_regs+0x1a/0x20
> > > May 11 10:05:00 ans-ebb3 kernel: [<c06d0d7a>]
> nmi_watchdog_tick+0x9b/0x162
> > > May 11 10:05:00 ans-ebb3 kernel: [<c06d02e1>] do_nmi+0xd1/0x2e1
> > > May 11 10:05:00 ans-ebb3 kernel: [<c056355d>] ?
> ltt_chan_for_each_channel+0x35/0x4f
> > > May 11 10:05:00 ans-ebb3 kernel: [<c05628df>] ?
> ltt_chanbuf_idle_switch+0x0/0x1c
> > > May 11 10:05:00 ans-ebb3 kernel: [<c06cfd41>]
> nmi_stack_correct+0x28/0x2d
> > > May 11 10:05:00 ans-ebb3 kernel: [<c062e4fa>] ? poll_idle+0x1e/0x5c
> > > May 11 10:05:00 ans-ebb3 kernel: [<c062e7c9>]
> cpuidle_idle_call+0x6c/0xdf
> > > May 11 10:05:00 ans-ebb3 kernel: [<c0401c0d>] cpu_idle+0x49/0x80
> > > May 11 10:05:00 ans-ebb3 kernel: [<c06ca177>]
> start_secondary+0x1b9/0x1be
> > > May 11 10:05:00 ans-ebb3 kernel: NMI backtrace for cpu 0
> > > May 11 10:05:00 ans-ebb3 kernel: Modules linked in: battery sbshc
> ehci_hcd sbs scsi_dh ohci_hcd dm_multipath uhci_hcd scsi_mod dm_mirror
> sd_mod libata ahci dm_mod dm_log dm_region_hash tpm_bios tpm intel_agp
> iTCO_vendor_support i2c_core pcspkr tpm_tis iTCO_wdt i2c_i801 autofs4
> e1000e button serio_raw sg output video ac parport lp parport_pc ipv6
> nvidia(P) [last unloaded: nvidia]
> > > May 11 10:05:00 ans-ebb3 kernel:
> > > May 11 10:05:00 ans-ebb3 kernel: Pid: 0, comm: swapper Tainted: P
> 2.6.33.2-rt13.11.trace #10 PXT /To Be Filled By O.E.M.
> > > May 11 10:05:00 ans-ebb3 kernel: EIP: 0060:[<c0570ab6>] EFLAGS:
> 00000807 CPU: 0
> > > May 11 10:05:00 ans-ebb3 kernel: EIP is at delay_tsc+0x0/0x8a
> > > May 11 10:05:00 ans-ebb3 kernel: EAX: 001c7b29 EBX: 00000001 ECX:
> 04f29000 EDX: 001c7b28
> > > May 11 10:05:00 ans-ebb3 kernel: ESI: 00000000 EDI: c084a6c0 EBP:
> c0828e6c ESP: c0828e68
> > > May 11 10:05:00 ans-ebb3 kernel: DS: 007b ES: 007b FS: 00d8 GS:
> 0000 SS: 0068 preempt:04020002
> > > May 11 10:05:00 ans-ebb3 kernel: Process swapper (pid: 0,
> ti=c0828000 task=c08407a0 task.ti=c0828000)
> > > May 11 10:05:00 ans-ebb3 kernel: Stack:
> > > May 11 10:05:00 ans-ebb3 kernel: c0570a4f c0828e78 c0418e84
> c084a740 c0828eb0 c047c35b c07c1944 00000000
> > > May 11 10:05:00 ans-ebb3 kernel: <0> 00002712 c5805268 c084a6c0
> c084a6ec 00000003 c084a740 00000083 00000000
> > > May 11 10:05:00 ans-ebb3 kernel: <0> 00000000 c08407a0 c0828ec0
> c047c45f 00000000 00000000 c0828ed4 c0441fbd
> > > May 11 10:05:00 ans-ebb3 kernel: Call Trace:
> > > May 11 10:05:00 ans-ebb3 kernel: [<c0570a4f>] ?
> __const_udelay+0x2f/0x31
> > > May 11 10:05:01 ans-ebb3 kernel: [<c0418e84>] ?
> arch_trigger_all_cpu_backtrace+0x42/0x4f
> > > May 11 10:05:01 ans-ebb3 kernel: [<c047c35b>] ?
> __rcu_pending+0x258/0x309
> > > May 11 10:05:01 ans-ebb3 kernel: [<c047c45f>] ?
> rcu_check_callbacks+0x53/0x114
> > > May 11 10:05:01 ans-ebb3 kernel: [<c0441fbd>] ?
> update_process_times+0x32/0x43
> > > May 11 10:05:01 ans-ebb3 kernel: [<c04587b7>] ?
> tick_sched_timer+0x6d/0x9b
> > > May 11 10:05:01 ans-ebb3 kernel: [<c045874a>] ?
> tick_sched_timer+0x0/0x9b
> > > May 11 10:05:01 ans-ebb3 kernel: [<c044f8fc>] ?
> __run_hrtimer+0xeb/0x154
> > > May 11 10:05:01 ans-ebb3 kernel: [<c044fc4d>] ?
> hrtimer_interrupt+0xed/0x21e
> > > May 11 10:05:01 ans-ebb3 kernel: [<c04518c5>] ?
> sched_clock_idle_wakeup_event+0x16/0x18
> > > May 11 10:05:01 ans-ebb3 kernel: [<c0418512>] ?
> smp_apic_timer_interrupt+0xb4/0x106
> > > May 11 10:05:01 ans-ebb3 kernel: [<c06cfa66>] ?
> apic_timer_interrupt+0x2a/0x30
> > > May 11 10:05:01 ans-ebb3 kernel: [<c062e4f6>] ? poll_idle+0x1a/0x5c
> > > May 11 10:05:01 ans-ebb3 kernel: [<c062e7c9>] ?
> cpuidle_idle_call+0x6c/0xdf
> > > May 11 10:05:01 ans-ebb3 kernel: [<c0401c0d>] ? cpu_idle+0x49/0x80
> > > May 11 10:05:01 ans-ebb3 kernel: [<c06bdde4>] ? rest_init+0x80/0x82
> > > May 11 10:05:01 ans-ebb3 kernel: [<c087a859>] ?
> start_kernel+0x2fb/0x300
> > > May 11 10:05:01 ans-ebb3 kernel: [<c087a08c>] ?
> i386_start_kernel+0x8c/0x91
> > > May 11 10:05:01 ans-ebb3 kernel: Code: c0 8b 0c 8d 18 7b 87 c0 6b c0
> 14 ba 40 ff 8d c0 55 89 e5 69 94 0a 98 00 00 00 fa 00 00 00 f7 e2 8d 42
> 01 ff 15 90 84 85 c0 5d c3 <55> 89 e5 57 56 89 c6 53 83 ec 04 89 e0 25
> 00 f0 ff ff ff 40 14
> > > May 11 10:05:01 ans-ebb3 kernel: Call Trace:
> > > May 11 10:05:01 ans-ebb3 kernel: [<c0570a4f>] ?
> __const_udelay+0x2f/0x31
> > > May 11 10:05:01 ans-ebb3 kernel: [<c0418e84>]
> arch_trigger_all_cpu_backtrace+0x42/0x4f
> > > May 11 10:05:01 ans-ebb3 kernel: [<c047c35b>]
> __rcu_pending+0x258/0x309
> > > May 11 10:05:01 ans-ebb3 kernel: [<c047c45f>]
> rcu_check_callbacks+0x53/0x114
> > > May 11 10:05:01 ans-ebb3 kernel: [<c0441fbd>]
> update_process_times+0x32/0x43
> > > May 11 10:05:01 ans-ebb3 kernel: [<c04587b7>]
> tick_sched_timer+0x6d/0x9b
> > > May 11 10:05:01 ans-ebb3 kernel: [<c045874a>] ?
> tick_sched_timer+0x0/0x9b
> > > May 11 10:05:01 ans-ebb3 kernel: [<c044f8fc>]
> __run_hrtimer+0xeb/0x154
> > > May 11 10:05:01 ans-ebb3 kernel: [<c044fc4d>]
> hrtimer_interrupt+0xed/0x21e
> > > May 11 10:05:01 ans-ebb3 kernel: [<c04518c5>] ?
> sched_clock_idle_wakeup_event+0x16/0x18
> > > May 11 10:05:01 ans-ebb3 kernel: [<c0418512>]
> smp_apic_timer_interrupt+0xb4/0x106
> > > May 11 10:05:01 ans-ebb3 kernel: [<c06cfa66>]
> apic_timer_interrupt+0x2a/0x30
> > > May 11 10:05:01 ans-ebb3 kernel: [<c062e4f6>] ? poll_idle+0x1a/0x5c
> > > May 11 10:05:01 ans-ebb3 kernel: [<c062e7c9>]
> cpuidle_idle_call+0x6c/0xdf
> > > May 11 10:05:01 ans-ebb3 kernel: [<c0401c0d>] cpu_idle+0x49/0x80
> > > May 11 10:05:01 ans-ebb3 kernel: [<c06bdde4>] rest_init+0x80/0x82
> > > May 11 10:05:01 ans-ebb3 kernel: [<c087a859>]
> start_kernel+0x2fb/0x300
> > > May 11 10:05:01 ans-ebb3 kernel: [<c087a08c>]
> i386_start_kernel+0x8c/0x91
> > > May 11 10:05:01 ans-ebb3 kernel: Pid: 0, comm: swapper Tainted: P
> 2.6.33.2-rt13.11.trace #10
> > > May 11 10:05:01 ans-ebb3 kernel: Call Trace:
> > > May 11 10:05:01 ans-ebb3 kernel: [<c04019d4>] ? show_regs+0x1a/0x20
> > > May 11 10:05:01 ans-ebb3 kernel: [<c06d0d7a>]
> nmi_watchdog_tick+0x9b/0x162
> > > May 11 10:05:01 ans-ebb3 kernel: [<c06d02e1>] do_nmi+0xd1/0x2e1
> > > May 11 10:05:01 ans-ebb3 kernel: [<c05645a8>] ?
> ltt_vtrace+0x0/0x79b
> > > May 11 10:05:02 ans-ebb3 kernel: [<c06cfd41>]
> nmi_stack_correct+0x28/0x2d
> > > May 11 10:05:02 ans-ebb3 kernel: [<c0570ab6>] ? delay_tsc+0x0/0x8a
> > > May 11 10:05:02 ans-ebb3 kernel: [<c0570a4f>] ?
> __const_udelay+0x2f/0x31
> > > May 11 10:05:02 ans-ebb3 kernel: [<c0418e84>]
> arch_trigger_all_cpu_backtrace+0x42/0x4f
> > > May 11 10:05:02 ans-ebb3 kernel: [<c047c35b>]
> __rcu_pending+0x258/0x309
> > > May 11 10:05:02 ans-ebb3 kernel: [<c047c45f>]
> rcu_check_callbacks+0x53/0x114
> > > May 11 10:05:02 ans-ebb3 kernel: [<c0441fbd>]
> update_process_times+0x32/0x43
> > > May 11 10:05:02 ans-ebb3 kernel: [<c04587b7>]
> tick_sched_timer+0x6d/0x9b
> > > May 11 10:05:02 ans-ebb3 kernel: [<c045874a>] ?
> tick_sched_timer+0x0/0x9b
> > > May 11 10:05:02 ans-ebb3 kernel: [<c044f8fc>]
> __run_hrtimer+0xeb/0x154
> > > May 11 10:05:02 ans-ebb3 kernel: [<c044fc4d>]
> hrtimer_interrupt+0xed/0x21e
> > > May 11 10:05:02 ans-ebb3 kernel: [<c04518c5>] ?
> sched_clock_idle_wakeup_event+0x16/0x18
> > > May 11 10:05:02 ans-ebb3 kernel: [<c0418512>]
> smp_apic_timer_interrupt+0xb4/0x106
> > > May 11 10:05:02 ans-ebb3 kernel: [<c06cfa66>]
> apic_timer_interrupt+0x2a/0x30
> > > May 11 10:05:02 ans-ebb3 kernel: [<c062e4f6>] ? poll_idle+0x1a/0x5c
> > > May 11 10:05:02 ans-ebb3 kernel: [<c062e7c9>]
> cpuidle_idle_call+0x6c/0xdf
> > > May 11 10:05:02 ans-ebb3 kernel: [<c0401c0d>] cpu_idle+0x49/0x80
> > > May 11 10:05:02 ans-ebb3 kernel: [<c06bdde4>] rest_init+0x80/0x82
> > > May 11 10:05:02 ans-ebb3 kernel: [<c087a859>]
> start_kernel+0x2fb/0x300
> > > May 11 10:05:02 ans-ebb3 kernel: [<c087a08c>]
> i386_start_kernel+0x8c/0x91
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: Mathieu Desnoyers [mailto:[email protected]]
> > > Sent: Tue 5/11/2010 7:59 AM
> > > To: John P. Paul
> > > Cc: [email protected]
> > > Subject: Re: [ltt-dev] lttctl locks up with RT Linux
> > >
> > > * [email protected] ([email protected]) wrote:
> > > > Hey Mathieu:
> > > >
> > > > Thanks for looking at this. I'm a bit new to debugging at this
> level, so
> > > > you may need to provide me a bit more info on what you need. I
> attempted
> > > > to use "pstack" on the lttctl and lttd tasks ... no luck as pstack
> also
> > > > locked up.
> > > >
> > > > I put a bit of tracing into liblttctl and discovered the lockup
> occurs
> > > > when a write of "traceName" (whatever traceName happens to be)
> occurs to
> > > > the "/mnt/debugfs/ltt/destroy_trace" file.
> > > >
> > > > I'm guessing that you would like some tracing of the ltt kernel
> module.
> > > > Is there something that I can turn on, or another way I could get
> a
> > > > stack dump of that module after lockup? I'll do a little research
> this
> > > > weekend on kernel debugging techniques.
> > > >
> > > > I can certainly sprinkle in some printk statements in the ltt
> kernel
> > > > module source. Doing provided the following info:
> > > >
> > > > - Control entered _ltt_trace_destroy (single underscore)
> > > > - Control entered del_timer_sync(<t_async_wakeup_timer) and
> never
> > > > returned
> > > >
> > > > Does that help, or should I continue farther down this path?
> > >
> > > Can you try the following patch to see if it fixes your problem ?
> > >
> > >
> > > lttng fix rt kernel teardown deadlock
> > >
> > > LTTng has a teardown bug on RT (deadlock):
> > >
> > > Deleting a timer (sync) while holding the traces mutex, and the
> handler takes
> > > the same mutex, which leads to a deadlock.
> > >
> > > Fix this by taking a RCU read lock in the timer (instead of the
> RT-specific fix
> > > using the mutex), and by doing synchronize_rcu() in addition to
> > > synchronize_sched() upon updates.
> > >
> > > Signed-off-by: Mathieu Desnoyers <[email protected]>
> > > ---
> > > ltt/ltt-tracer.c | 28 ++++++++++++++++++----------
> > > 1 file changed, 18 insertions(+), 10 deletions(-)
> > >
> > > Index: linux-2.6-lttng/ltt/ltt-tracer.c
> > > ===================================================================
> > > --- linux-2.6-lttng.orig/ltt/ltt-tracer.c 2010-05-11
> 07:50:46.000000000 -0400
> > > +++ linux-2.6-lttng/ltt/ltt-tracer.c 2010-05-11
> 07:55:46.000000000 -0400
> > > @@ -41,6 +41,14 @@
> > > #include <linux/vmalloc.h>
> > > #include <asm/atomic.h>
> > >
> > > +static void synchronize_trace(void)
> > > +{
> > > + synchronize_sched();
> > > +#ifdef CONFIG_PREEMPT_RT
> > > + synchronize_rcu();
> > > +#endif
> > > +}
> > > +
> > > static void async_wakeup(unsigned long data);
> > >
> > > static DEFINE_TIMER(ltt_async_wakeup_timer, async_wakeup, 0, 0);
> > > @@ -321,7 +329,7 @@ void ltt_module_unregister(enum ltt_modu
> > > ltt_filter_unregister();
> > > ltt_run_filter_owner = NULL;
> > > /* Wait for preempt sections to finish */
> > > - synchronize_sched();
> > > + synchronize_trace();
> > > break;
> > > case LTT_FUNCTION_FILTER_CONTROL:
> > > ltt_filter_control_functor = ltt_filter_control_default;
> > > @@ -429,13 +437,13 @@ static void async_wakeup(unsigned long d
> > > * PREEMPT_RT does not allow spinlocks to be taken within
> preempt
> > > * disable sections (spinlock taken in wake_up). However,
> mainline won't
> > > * allow mutex to be taken in interrupt context. Ugly.
> > > - * A proper way to do this would be to turn the timer into a
> > > - * periodically woken up thread, but it adds to the footprint.
> > > + * Take a standard RCU read lock for RT kernels, which imply
> that we
> > > + * also have to synchronize_rcu() upon updates.
> > > */
> > > #ifndef CONFIG_PREEMPT_RT
> > > rcu_read_lock_sched();
> > > #else
> > > - ltt_lock_traces();
> > > + rcu_read_lock();
> > > #endif
> > > list_for_each_entry_rcu(trace, <t_traces.head, list) {
> > > trace_async_wakeup(trace);
> > > @@ -443,7 +451,7 @@ static void async_wakeup(unsigned long d
> > > #ifndef CONFIG_PREEMPT_RT
> > > rcu_read_unlock_sched();
> > > #else
> > > - ltt_unlock_traces();
> > > + rcu_read_unlock();
> > > #endif
> > >
> > > mod_timer(<t_async_wakeup_timer, jiffies +
> LTT_PERCPU_TIMER_INTERVAL);
> > > @@ -901,7 +909,7 @@ int ltt_trace_alloc(const char *trace_na
> > > set_kernel_trace_flag_all_tasks();
> > > }
> > > list_add_rcu(&trace->list, <t_traces.head);
> > > - synchronize_sched();
> > > + synchronize_trace();
> > >
> > > ltt_unlock_traces();
> > >
> > > @@ -974,7 +982,7 @@ static int _ltt_trace_destroy(struct ltt
> > > }
> > > /* Everything went fine */
> > > list_del_rcu(&trace->list);
> > > - synchronize_sched();
> > > + synchronize_trace();
> > > if (list_empty(<t_traces.head)) {
> > > clear_kernel_trace_flag_all_tasks();
> > > /*
> > > @@ -1195,7 +1203,7 @@ static int _ltt_trace_stop(struct ltt_tr
> > > trace->nr_channels);
> > > trace->active = 0;
> > > ltt_traces.num_active_traces--;
> > > - synchronize_sched(); /* Wait for each tracing to be
> finished */
> > > + synchronize_trace(); /* Wait for each tracing to be
> finished */
> > > }
> > > module_put(ltt_run_filter_owner);
> > > /* Everything went fine */
> > > @@ -1327,12 +1335,12 @@ static void __exit ltt_exit(void)
> > > list_for_each_entry_rcu(trace, <t_traces.head, list)
> > > _ltt_trace_stop(trace);
> > > /* Wait for quiescent state. Readers have preemption disabled.
> */
> > > - synchronize_sched();
> > > + synchronize_trace();
> > > /* Safe iteration is now permitted. It does not have to be
> RCU-safe
> > > * because no readers are left. */
> > > list_for_each_safe(pos, n, <t_traces.head) {
> > > trace = container_of(pos, struct ltt_trace, list);
> > > - /* _ltt_trace_destroy does a synchronize_sched() */
> > > + /* _ltt_trace_destroy does a synchronize_trace() */
> > > _ltt_trace_destroy(trace);
> > > __ltt_trace_destroy(trace);
> > > }
> > >
> > >
> > >
> > > --
> > > This is an e-mail from General Dynamics Robotic Systems. It is for
> the intended recipient only and may contain confidential and privileged
> information. No one else may read, print, store, copy, forward or act in
> reliance on it or its attachments. If you are not the intended
> recipient, please return this message to the sender and delete the
> message and any attachments from your computer. Your cooperation is
> appreciated.
> > >
> >
> > --
> > Mathieu Desnoyers
> > Operating System Efficiency R&D Consultant
> > EfficiOS Inc.
> > http://www.efficios.com
>
> --
> This is an e-mail from General Dynamics Robotic Systems. It is for the
> intended recipient only and may contain confidential and privileged
> information. No one else may read, print, store, copy, forward or act in
> reliance on it or its attachments. If you are not the intended recipient,
> please return this message to the sender and delete the message and any
> attachments from your computer. Your cooperation is appreciated.
>
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