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Date: Thu, 13 Feb 2014 11:31:15 +0800
From: Lai Jiangshan <laijs@...fujitsu.com>
To: jjherne@...ux.vnet.ibm.com
CC: Tejun Heo <tj@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: Subject: Warning in workqueue.c
On 02/12/2014 11:18 PM, Jason J. Herne wrote:
> On 02/10/2014 06:17 PM, Tejun Heo wrote:
>> Hello,
>>
>> On Mon, Feb 10, 2014 at 10:32:11AM -0500, Jason J. Herne wrote:
>>> [ 950.778485] XXX: worker->flags=0x1 pool->flags=0x0 cpu=6
>>> pool->cpu=2 rescue_wq= (null)
>>> [ 950.778488] XXX: last_unbind=-7 last_rebind=0
>>> last_rebound_clear=0 nr_exected_after_rebound_clear=0
>>> [ 950.778492] XXX: cpus_allowed=2
>>> [ 950.778495] XXX: cpus_allowed_after_rebinding=2
>>
>> So, everything looks kosher from workqueue side. Weird. cpus_allowed
>> is properly set and everything. The worker just isn't running on the
>> cpu it's supposed to be on. Can you please try the following?
>
>
> Thanks for the fast responses. Here is the output from the last patch:
>
>
> [34437.173991] WARNING: at kernel/workqueue.c:2156
> [34437.173993] Modules linked in: ipt_MASQUERADE iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack xt_CHECKSUM iptable_mangle bridge stp llc ip6table_filter ip6_tables ebtable_nat ebtables iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi qeth_l2 tape_3590 tape tape_class vhost_net tun vhost macvtap macvlan lcs dasd_eckd_mod dasd_mod qeth ccwgroup zfcp scsi_transport_fc scsi_tgt qdio dm_multipath [last unloaded: kvm]
> [34437.174030] CPU: 2 PID: 12 Comm: kworker/1:0 Not tainted 3.14.0-rc1 #1
> [34437.174034] task: 00000000f7c9e4c0 ti: 00000000f7cbc000 task.ti: 00000000f7cbc000
> [34437.174046] Krnl PSW : 0404c00180000000 000000000015b406 (process_one_work+0x61a/0x640)
> [34437.174051] R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 EA:3
> Krnl GPRS: 000000007c325b00 0000000000bc2a52 00000000f7f52780 0000000000000001
> [34437.174057] 0000000000000000 0000000000000002 0000000000000001 0000000000bc2a4e
> [34437.174061] 0000000000000000 0000000084a13500 0000000084a0f000 0000000084a0f018
> [34437.174065] 00000000f7f52780 0000000000735d18 00000000f7cbfdd0 00000000f7cbfd58
> [34437.174085] Krnl Code: 000000000015b3fa: 92013000 mvi 0(%r3),1
> 000000000015b3fe: a7f4ff31 brc 15,15b260
> #000000000015b402: a7f40001 brc 15,15b404
> >000000000015b406: 92011000 mvi 0(%r1),1
> 000000000015b40a: a7f4fe84 brc 15,15b112
> 000000000015b40e: 41102018 la %r1,24(%r2)
> 000000000015b412: e31020180020 cg %r1,24(%r2)
> 000000000015b418: a784ff59 brc 8,15b2ca
> [34437.174115] Call Trace:
> [34437.174118] ([<000000000015b0e0>] process_one_work+0x2f4/0x640)
> [34437.174122] [<000000000015ba0e>] worker_thread+0x19a/0x3c0
> [34437.174126] [<0000000000164842>] kthread+0x10e/0x128
> [34437.174132] [<0000000000728e56>] kernel_thread_starter+0x6/0xc
> [34437.174136] [<0000000000728e50>] kernel_thread_starter+0x0/0xc
> [34437.174138] Last Breaking-Event-Address:
> [34437.174141] [<000000000015b402>] process_one_work+0x616/0x640
> [34437.174144] ---[ end trace 52d8ee96597a2415 ]---
> [34437.174148] XXX: worker->flags=0x1 pool->flags=0x0 cpu=2 pool->cpu=1(1) rescue_wq= (null)
> [34437.174152] XXX: last_unbind=-34 last_rebind=0 last_rebound_clear=0 nr_exected_after_rebound_clear=0
> [34437.174156] XXX: cpus_allowed=1
> [34437.174158] XXX: cpus_allowed_after_rebinding=1
> [34437.174161] BUG: scheduling while atomic: kworker/1:0/12/0x00000002
> [34437.174164] Modules linked in: ipt_MASQUERADE iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack xt_CHECKSUM iptable_mangle bridge stp llc ip6table_filter ip6_tables ebtable_nat ebtables iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi qeth_l2 tape_3590 tape tape_class vhost_net tun vhost macvtap macvlan lcs dasd_eckd_mod dasd_mod qeth ccwgroup zfcp scsi_transport_fc scsi_tgt qdio dm_multipath [last unloaded: kvm]
> [34437.174194] CPU: 2 PID: 12 Comm: kworker/1:0 Tainted: G W 3.14.0-rc1 #1
> [34437.174197] 00000000f7cbfb80 00000000f7cbfb90 0000000000000002 0000000000000000
> 00000000f7cbfc20 00000000f7cbfb98 00000000f7cbfb98 0000000000115f6a
> 0000000000000003 0000000000c4da00 000000000000000a 000000000000000a
> 00000000f7cbfbe0 00000000f7cbfb80 0000000000000000 0000000000000000
> 0000000000000000 0000000000115f6a 00000000f7cbfb80 00000000f7cbfbd0
> [34437.174273] Call Trace:
> [34437.174279] ([<0000000000115e5c>] show_trace+0x100/0x148)
> [34437.174282] [<0000000000115f18>] show_stack+0x74/0xf4
> [34437.174288] [<0000000000720a9c>] dump_stack+0x88/0xb8
> [34437.174291] [<000000000071aa40>] __schedule_bug+0x78/0x90
> [34437.174295] [<00000000007237e4>] __schedule+0xb8c/0xbac
> [34437.174299] [<000000000015b21e>] process_one_work+0x432/0x640
> [34437.174302] [<000000000015ba0e>] worker_thread+0x19a/0x3c0
> [34437.174306] [<0000000000164842>] kthread+0x10e/0x128
> [34437.174309] [<0000000000728e56>] kernel_thread_starter+0x6/0xc
> [34437.174313] [<0000000000728e50>] kernel_thread_starter+0x0/0xc
> [34437.174317] XXX: after schedule(), cpu=2
Could you use the following patch for test if Tejun doesn't give you a new one.
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index b010eac..cdd7a10 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -825,6 +825,7 @@ void wq_worker_waking_up(struct task_struct *task, int cpu)
{
struct worker *worker = kthread_data(task);
+ worker->wake_up = jiffies;
if (!(worker->flags & WORKER_NOT_RUNNING)) {
WARN_ON_ONCE(worker->pool->cpu != cpu);
atomic_inc(&worker->pool->nr_running);
@@ -851,6 +852,7 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task, int cpu)
struct worker *worker = kthread_data(task), *to_wakeup = NULL;
struct worker_pool *pool;
+ worker->sleep = jiffies;
/*
* Rescuers, which may not have all the fields set up like normal
* workers, also reach here, let's not access anything before
@@ -2134,6 +2136,7 @@ __acquires(&pool->lock)
bool cpu_intensive = pwq->wq->flags & WQ_CPU_INTENSIVE;
int work_color;
struct worker *collision;
+ int worker_bug = 0;
#ifdef CONFIG_LOCKDEP
/*
* It is permissible to free the struct work_struct from
@@ -2151,9 +2154,31 @@ __acquires(&pool->lock)
* necessary to avoid spurious warnings from rescuers servicing the
* unbound or a disassociated pool.
*/
- WARN_ON_ONCE(!(worker->flags & WORKER_UNBOUND) &&
- !(pool->flags & POOL_DISASSOCIATED) &&
- raw_smp_processor_id() != pool->cpu);
+ if (WARN_ON_ONCE(!(worker->flags & WORKER_UNBOUND) &&
+ !(pool->flags & POOL_DISASSOCIATED) &&
+ raw_smp_processor_id() != pool->cpu)) {
+ static char buf[PAGE_SIZE];
+ unsigned long now = jiffies;
+
+ worker_bug = 1;
+ pr_warning("XXX: worker->flags=0x%x pool->flags=0x%x cpu=%d pool->cpu=%d(%d) rescue_wq=%p\n",
+ worker->flags, pool->flags, raw_smp_processor_id(),
+ pool->cpu, cpu_online(pool->cpu), worker->rescue_wq);
+ pr_warning("XXX: last_unbind=%ld last_rebind=%ld last_rebound_clear=%ld nr_exected_after_rebound_clear=%d\n",
+ worker->last_unbind ? worker->last_unbind - now : 999,
+ worker->last_rebind ? worker->last_rebind - now : 999,
+ worker->last_rebound_clear ? worker->last_rebound_clear - now : 999,
+ worker->nr_executed_after_rebound_clear);
+ pr_warning("XXX: sleep=%ld wakeup=%ld\n",
+ worker->sleep ? worker->sleep - now : 999,
+ worker->wake_up ? worker->wake_up - now : 999);
+
+ cpulist_scnprintf(buf, sizeof(buf), ¤t->cpus_allowed);
+ pr_warning("XXX: cpus_allowed=%s\n", buf);
+
+ cpulist_scnprintf(buf, sizeof(buf), &worker->cpus_allowed_after_rebinding);
+ pr_warning("XXX: cpus_allowed_after_rebinding=%s\n", buf);
+ }
/*
* A single work shouldn't be executed concurrently by
@@ -2199,8 +2224,15 @@ __acquires(&pool->lock)
*/
set_work_pool_and_clear_pending(work, pool->id);
+ worker->nr_executed_after_rebound_clear++;
+
spin_unlock_irq(&pool->lock);
+ if (worker_bug) {
+ schedule();
+
+ pr_warning("XXX: after schedule(), cpu=%d\n", raw_smp_processor_id());
+ }
lock_map_acquire_read(&pwq->wq->lockdep_map);
lock_map_acquire(&lockdep_map);
trace_workqueue_execute_start(work);
@@ -2298,6 +2330,7 @@ woke_up:
}
worker_leave_idle(worker);
+ worker->wake_up = jiffies;
recheck:
/* no more worker necessary? */
if (!need_more_worker(pool))
@@ -2321,6 +2354,10 @@ recheck:
* management if applicable and concurrency management is restored
* after being rebound. See rebind_workers() for details.
*/
+ if (worker->flags & WORKER_REBOUND) {
+ worker->last_rebound_clear = jiffies;
+ worker->nr_executed_after_rebound_clear = 0;
+ }
worker_clr_flags(worker, WORKER_PREP | WORKER_REBOUND);
do {
@@ -2341,6 +2378,7 @@ recheck:
worker_set_flags(worker, WORKER_PREP, false);
sleep:
+ worker->sleep = jiffies;
if (unlikely(need_to_manage_workers(pool)) && manage_workers(worker))
goto recheck;
@@ -4576,8 +4614,10 @@ static void wq_unbind_fn(struct work_struct *work)
* before the last CPU down must be on the cpu. After
* this, they may become diasporas.
*/
- for_each_pool_worker(worker, wi, pool)
+ for_each_pool_worker(worker, wi, pool) {
worker->flags |= WORKER_UNBOUND;
+ worker->last_unbind = jiffies;
+ }
pool->flags |= POOL_DISASSOCIATED;
@@ -4633,9 +4673,13 @@ static void rebind_workers(struct worker_pool *pool)
* of all workers first and then clear UNBOUND. As we're called
* from CPU_ONLINE, the following shouldn't fail.
*/
- for_each_pool_worker(worker, wi, pool)
+ for_each_pool_worker(worker, wi, pool) {
WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task,
pool->attrs->cpumask) < 0);
+ worker->last_rebind = jiffies;
+ cpumask_copy(&worker->cpus_allowed_after_rebinding,
+ &worker->task->cpus_allowed);
+ }
spin_lock_irq(&pool->lock);
diff --git a/kernel/workqueue_internal.h b/kernel/workqueue_internal.h
index 7e2204d..db17e2c 100644
--- a/kernel/workqueue_internal.h
+++ b/kernel/workqueue_internal.h
@@ -50,6 +50,13 @@ struct worker {
/* used only by rescuers to point to the target workqueue */
struct workqueue_struct *rescue_wq; /* I: the workqueue to rescue */
+ unsigned long last_unbind;
+ unsigned long last_rebind;
+ unsigned long sleep;
+ unsigned long wake_up;
+ unsigned long last_rebound_clear;
+ int nr_executed_after_rebound_clear;
+ cpumask_t cpus_allowed_after_rebinding;
};
/**
--
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