From c38f96080955854e54df9cb392bc674e1ae330e1 Mon Sep 17 00:00:00 2001 From: Jan Glauber Date: Thu, 26 Mar 2009 15:24:26 +0100 Subject: [PATCH] [S390] qdio: proper kill of qdio tasklets 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 Signed-off-by: Martin Schwidefsky --- drivers/s390/cio/qdio_main.c | 35 ++++++++++++++++++++++----------- drivers/s390/cio/qdio_thinint.c | 8 ++++---- 2 files changed, 28 insertions(+), 15 deletions(-) diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c index fa902703996c..1974ec7bf0ed 100644 --- a/drivers/s390/cio/qdio_main.c +++ b/drivers/s390/cio/qdio_main.c @@ -778,21 +778,17 @@ static void __qdio_outbound_processing(struct qdio_q *q) 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(struct qdio_q *q) 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 long data) 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 qdio_irq *irq_ptr) 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 ccw_device *cdev) 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 *cdev, int how) 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_q *q, unsigned int callflags, qdio_perf_stat_inc(&perf_stats.fast_requeue); } out: - /* Fixme: could wait forever if called from process context */ tasklet_schedule(&q->tasklet); } diff --git a/drivers/s390/cio/qdio_thinint.c b/drivers/s390/cio/qdio_thinint.c index 981044c83864..c7c5512a892e 100644 --- a/drivers/s390/cio/qdio_thinint.c +++ b/drivers/s390/cio/qdio_thinint.c @@ -101,7 +101,6 @@ void tiqdio_add_input_queues(struct qdio_irq *irq_ptr) 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(struct qdio_q *q) */ 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); } }