[patch/s390 37/46] qdio: proper kill of qdio tasklets
From: Martin Schwidefsky
Date: Wed Feb 25 2009 - 10:16:45 EST
From: Jan Glauber <jang@xxxxxxxxxxxxxxxxxx>
The queue tasklets were stopped with tasklet_disable. Although tasklet_disable
prevents the tasklet from beeing executed it is still possible that a tasklet
is scheduled on a CPU at that point. A following qdio_establish calls
tasklet_init which clears the tasklet count and the tasklet state leading to
the following Oops:
<2>kernel BUG at kernel/softirq.c:392!
<4>illegal operation: 0001 [#1] SMP
<4>Modules linked in: iptable_filter ip_tables x_tables dm_round_robin dm_multipath scsi_dh sg sd_mod crc_t10dif nfs lockd nfs
_acl sunrpc fuse loop dm_mod qeth_l3 ipv6 zfcp qeth scsi_transport_fc qdio scsi_tgt scsi_mod chsc_sch ccwgroup dasd_eckd_mod dasdm
od ext3 mbcache jbd
<4>Supported: Yes
<4>CPU: 0 Not tainted 2.6.27.13-1.1.mz13-default #1
<4>Process blast.LzS_64 (pid: 16445, task: 000000006cc02538, ksp: 000000006cb67998)
<4>Krnl PSW : 0704c00180000000 00000000001399f4 (tasklet_action+0xc8/0x1d4)
<4> R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 EA:3
<4>Krnl GPRS: ffffffff00000030 0000000000000002 0000000000000002 fffffffffffffffe
<4> 000000000013aabe 00000000003b6a18 fffffffffffffffd 0000000000000000
<4> 00000000006705a8 000000007d0914a8 000000007d0914b0 000000007fecfd30
<4> 0000000000000000 00000000003b63e8 000000007fecfd90 000000007fecfd30
<4>Krnl Code: 00000000001399e8: b9200021 cgr %r2,%r1
<4> 00000000001399ec: a7740004 brc 7,1399f4
<4> 00000000001399f0: a7f40001 brc 15,1399f2
<4> >00000000001399f4: c0100027e8ee larl %r1,636bd0
<4> 00000000001399fa: bf1f1008 icm %r1,15,8(%r1)
<4> 00000000001399fe: a7840019 brc 8,139a30
<4> 0000000000139a02: c0300027e8ef larl %r3,636be0
<4> 0000000000139a08: e3c030000004 lg %r12,0(%r3)
<4>Call Trace:
<4>([<0000000000139c12>] tasklet_hi_action+0x112/0x1d4)
<4> [<000000000013aabe>] __do_softirq+0xde/0x1c4
<4> [<000000000010fa2e>] do_softirq+0x96/0xb0
<4> [<000000000013a8d8>] irq_exit+0x70/0xcc
<4> [<000000000010d1d8>] do_extint+0xf0/0x110
<4> [<0000000000113b10>] ext_no_vtime+0x16/0x1a
<4> [<000003e0000a3662>] ext3_dirty_inode+0xe6/0xe8 [ext3]
<4>([<00000000001f6cf2>] __mark_inode_dirty+0x52/0x1d4)
<4> [<000003e0000a44f0>] ext3_ordered_write_end+0x138/0x190 [ext3]
<4> [<000000000018d5ec>] generic_perform_write+0x174/0x230
<4> [<0000000000190144>] generic_file_buffered_write+0xb4/0x194
<4> [<0000000000190864>] __generic_file_aio_write_nolock+0x418/0x454
<4> [<0000000000190ee2>] generic_file_aio_write+0x76/0xe4
<4> [<000003e0000a05c2>] ext3_file_write+0x3e/0xc8 [ext3]
<4> [<00000000001cc2fe>] do_sync_write+0xd6/0x120
<4> [<00000000001ccfc8>] vfs_write+0xac/0x184
<4> [<00000000001cd218>] SyS_write+0x68/0xe0
<4> [<0000000000113402>] sysc_noemu+0x10/0x16
<4> [<0000020000043188>] 0x20000043188
<4>Last Breaking-Event-Address:
<4> [<00000000001399f0>] tasklet_action+0xc4/0x1d4
<6>qdio: 0.0.c61b ZFCP on SC f67 using AI:1 QEBSM:0 PCI:1 TDD:1 SIGA: W AOP
<4> <0>Kernel panic - not syncing: Fatal exception in interrupt
Use tasklet_kill instead of tasklet_disbale. Since tasklet_schedule must not be
called after tasklet_kill use the QDIO_IRQ_STATE_STOPPED to inidicate that a
queue is going down and prevent further tasklet schedules in that case.
Remove superflous tasklet_schedule from input queue setup, at that time
the queues are not ready so the schedule results in a NOP.
Signed-off-by: Jan Glauber <jang@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
---
drivers/s390/cio/qdio_main.c | 35 ++++++++++++++++++++++++-----------
drivers/s390/cio/qdio_thinint.c | 8 ++++----
2 files changed, 28 insertions(+), 15 deletions(-)
Index: quilt-2.6/drivers/s390/cio/qdio_main.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/qdio_main.c
+++ quilt-2.6/drivers/s390/cio/qdio_main.c
@@ -778,21 +778,17 @@ static void __qdio_outbound_processing(s
spin_unlock_irqrestore(&q->lock, flags);
- if (queue_type(q) == QDIO_ZFCP_QFMT) {
+ if (queue_type(q) == QDIO_ZFCP_QFMT)
if (!pci_out_supported(q) && !qdio_outbound_q_done(q))
- tasklet_schedule(&q->tasklet);
- return;
- }
+ goto sched;
/* bail out for HiperSockets unicast queues */
if (queue_type(q) == QDIO_IQDIO_QFMT && !multicast_outbound(q))
return;
if ((queue_type(q) == QDIO_IQDIO_QFMT) &&
- (atomic_read(&q->nr_buf_used)) > QDIO_IQDIO_POLL_LVL) {
- tasklet_schedule(&q->tasklet);
- return;
- }
+ (atomic_read(&q->nr_buf_used)) > QDIO_IQDIO_POLL_LVL)
+ goto sched;
if (q->u.out.pci_out_enabled)
return;
@@ -810,6 +806,12 @@ static void __qdio_outbound_processing(s
qdio_perf_stat_inc(&perf_stats.debug_tl_out_timer);
}
}
+ return;
+
+sched:
+ if (unlikely(q->irq_ptr->state == QDIO_IRQ_STATE_STOPPED))
+ return;
+ tasklet_schedule(&q->tasklet);
}
/* outbound tasklet */
@@ -822,6 +824,9 @@ void qdio_outbound_processing(unsigned l
void qdio_outbound_timer(unsigned long data)
{
struct qdio_q *q = (struct qdio_q *)data;
+
+ if (unlikely(q->irq_ptr->state == QDIO_IRQ_STATE_STOPPED))
+ return;
tasklet_schedule(&q->tasklet);
}
@@ -863,6 +868,9 @@ static void qdio_int_handler_pci(struct
int i;
struct qdio_q *q;
+ if (unlikely(irq_ptr->state == QDIO_IRQ_STATE_STOPPED))
+ return;
+
qdio_perf_stat_inc(&perf_stats.pci_int);
for_each_input_queue(irq_ptr, q, i)
@@ -1090,11 +1098,11 @@ static void qdio_shutdown_queues(struct
int i;
for_each_input_queue(irq_ptr, q, i)
- tasklet_disable(&q->tasklet);
+ tasklet_kill(&q->tasklet);
for_each_output_queue(irq_ptr, q, i) {
- tasklet_disable(&q->tasklet);
del_timer(&q->u.out.timer);
+ tasklet_kill(&q->tasklet);
}
}
@@ -1125,6 +1133,12 @@ int qdio_shutdown(struct ccw_device *cde
return 0;
}
+ /*
+ * Indicate that the device is going down. Scheduling the queue
+ * tasklets is forbidden from here on.
+ */
+ qdio_set_state(irq_ptr, QDIO_IRQ_STATE_STOPPED);
+
tiqdio_remove_input_queues(irq_ptr);
qdio_shutdown_queues(cdev);
qdio_shutdown_debug_entries(irq_ptr, cdev);
@@ -1556,7 +1570,6 @@ static void handle_outbound(struct qdio_
qdio_perf_stat_inc(&perf_stats.fast_requeue);
}
out:
- /* Fixme: could wait forever if called from process context */
tasklet_schedule(&q->tasklet);
}
Index: quilt-2.6/drivers/s390/cio/qdio_thinint.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/qdio_thinint.c
+++ quilt-2.6/drivers/s390/cio/qdio_thinint.c
@@ -101,7 +101,6 @@ void tiqdio_add_input_queues(struct qdio
list_add_rcu(&q->entry, &tiq_list);
mutex_unlock(&tiq_list_lock);
xchg(irq_ptr->dsci, 1);
- tasklet_schedule(&tiqdio_tasklet);
}
/*
@@ -159,7 +158,6 @@ static void __tiqdio_inbound_processing(
*/
qdio_check_outbound_after_thinint(q);
-again:
if (!qdio_inbound_q_moved(q))
return;
@@ -167,7 +165,8 @@ again:
if (!tiqdio_inbound_q_done(q)) {
qdio_perf_stat_inc(&perf_stats.thinint_inbound_loop);
- goto again;
+ if (likely(q->irq_ptr->state != QDIO_IRQ_STATE_STOPPED))
+ tasklet_schedule(&q->tasklet);
}
qdio_stop_polling(q);
@@ -177,7 +176,8 @@ again:
*/
if (!tiqdio_inbound_q_done(q)) {
qdio_perf_stat_inc(&perf_stats.thinint_inbound_loop2);
- goto again;
+ if (likely(q->irq_ptr->state != QDIO_IRQ_STATE_STOPPED))
+ tasklet_schedule(&q->tasklet);
}
}
--
blue skies,
Martin.
"Reality continues to ruin my life." - Calvin.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/