Re: LTP case read_all_proc fails on qemux86-64 since 5.0-rc1

Jens Axboe
2019-01-25T19:32:33Z

On 1/24/19 8:20 PM, Jens Axboe wrote:
> On 1/24/19 8:14 PM, He Zhe wrote:
>>
>>
>> On 1/25/19 10:26 AM, Jens Axboe wrote:
>>> On 1/24/19 7:22 PM, He Zhe wrote:
>>>>
>>>> On 1/25/19 10:05 AM, Jens Axboe wrote:
>>>>> On 1/24/19 6:40 PM, He Zhe wrote:
>>>>>> On 1/24/19 11:40 PM, Jens Axboe wrote:
>>>>>>> On 1/24/19 1:23 AM, He Zhe wrote:
>>>>>>>> On 1/24/19 12:05 AM, Jens Axboe wrote:
>>>>>>>>> On 1/22/19 8:39 PM, Jens Axboe wrote:
>>>>>>>>>> On Jan 22, 2019, at 8:13 PM, He Zhe <zhe.he@windriver.com> wrote:
>>>>>>>>>>> LTP case read_all_proc(read_all -d /proc -q -r 10) often, but not every time, fails with the following call traces, since 600335205b8d "ide: convert to blk-mq"(5.0-rc1) till now(5.0-rc3).
>>>>>>>>>>>
>>>>>>>>>>> qemu-system-x86_64 -drive file=rootfs.ext4,if=virtio,format=raw -object rng-random,filename=/dev/urandom,id=rng0 -device virtio-rng-pci,rng=rng0 -nographic -m 16192 -smp cpus=12 -cpu core2duo -enable-kvm -serial mon:stdio -serial null -kernel bzImage -append 'root=/dev/vda rw highres=off console=ttyS0 mem=16192M'
>>>>>>>>>>>
>>>>>>>>>>> tst_test.c:1085: INFO: Timeout per run is 0h 05m 00s
>>>>>>>>>>> [ 47.080156] Warning: /proc/ide/hd?/settings interface is obsolete, and will be removed soon!
>>>>>>>>>>> [ 47.085330] ------------[ cut here ]------------
>>>>>>>>>>> [ 47.085810] kernel BUG at block/blk-mq.c:767!
>>>>>>>>>>> [ 47.086498] invalid opcode: 0000 [#1] PREEMPT SMP PTI
>>>>>>>>>>> [ 47.087022] CPU: 5 PID: 146 Comm: kworker/5:1H Not tainted 5.0.0-rc3 #1
>>>>>>>>>>> [ 47.087858] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
>>>>>>>>>>> [ 47.088992] Workqueue: kblockd blk_mq_run_work_fn
>>>>>>>>>>> [ 47.089469] RIP: 0010:blk_mq_add_to_requeue_list+0xc1/0xd0
>>>>>>>>>>> [ 47.090035] Code: 48 8d 53 48 49 8b 8c 24 b8 04 00 00 48 89 51 08 48 89 4b 48 49 8d 8c 24 b8 04 00 00 48 89 4b 50 49 89 94 24 b8 04 00 008
>>>>>>>>>>> [ 47.091930] RSP: 0018:ffff9e1ea4b43e40 EFLAGS: 00010002
>>>>>>>>>>> [ 47.092458] RAX: ffff9e1ea13c0048 RBX: ffff9e1ea13c0000 RCX: 0000000000000006
>>>>>>>>>>> [ 47.093181] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff9e1ea13c0000
>>>>>>>>>>> [ 47.093906] RBP: ffff9e1ea4b43e68 R08: ffffeb5bcf630680 R09: 0000000000000000
>>>>>>>>>>> [ 47.094626] R10: 0000000000000001 R11: 0000000000000012 R12: ffff9e1ea1033a40
>>>>>>>>>>> [ 47.095347] R13: ffff9e1ea13a8d00 R14: ffff9e1ea13a9000 R15: 0000000000000046
>>>>>>>>>>> [ 47.096071] FS: 0000000000000000(0000) GS:ffff9e1ea4b40000(0000) knlGS:0000000000000000
>>>>>>>>>>> [ 47.096898] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>>>>>>>>> [ 47.097477] CR2: 0000003fda41fda0 CR3: 00000003d8e6a000 CR4: 00000000000006e0
>>>>>>>>>>> [ 47.098203] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>>>>>>>>>>> [ 47.098929] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>>>>>>>>>>> [ 47.099650] Call Trace:
>>>>>>>>>>> [ 47.099910] <IRQ>
>>>>>>>>>>> [ 47.100128] blk_mq_requeue_request+0x58/0x60
>>>>>>>>>>> [ 47.100576] ide_requeue_and_plug+0x20/0x50
>>>>>>>>>>> [ 47.101014] ide_intr+0x21a/0x230
>>>>>>>>>>> [ 47.101362] ? idecd_open+0xc0/0xc0
>>>>>>>>>>> [ 47.101735] __handle_irq_event_percpu+0x43/0x1e0
>>>>>>>>>>> [ 47.102214] handle_irq_event_percpu+0x32/0x80
>>>>>>>>>>> [ 47.102668] handle_irq_event+0x39/0x60
>>>>>>>>>>> [ 47.103074] handle_edge_irq+0xe8/0x1c0
>>>>>>>>>>> [ 47.103470] handle_irq+0x20/0x30
>>>>>>>>>>> [ 47.103819] do_IRQ+0x46/0xe0
>>>>>>>>>>> [ 47.104128] common_interrupt+0xf/0xf
>>>>>>>>>>> [ 47.104505] </IRQ>
>>>>>>>>>>> [ 47.104731] RIP: 0010:ide_output_data+0xbc/0x100
>>>>>>>>>>> [ 47.105201] Code: 74 22 8d 41 ff 85 c9 74 24 49 8d 54 40 02 41 0f b7 00 66 41 89 01 49 83 c0 02 49 39 d0 75 ef 5b 41 5c 5d c3 4c 89 c6 445
>>>>>>>>>>> [ 47.107092] RSP: 0018:ffffbd508059bb18 EFLAGS: 00010246 ORIG_RAX: ffffffffffffffdd
>>>>>>>>>>> [ 47.107862] RAX: ffff9e1ea13a8800 RBX: ffff9e1ea13a9000 RCX: 0000000000000000
>>>>>>>>>>> [ 47.108581] RDX: 0000000000000170 RSI: ffff9e1ea13c012c RDI: 0000000000000000
>>>>>>>>>>> [ 47.109293] RBP: ffffbd508059bb28 R08: ffff9e1ea13c0120 R09: 0000000000000170
>>>>>>>>>>> [ 47.110016] R10: 000000000000000d R11: 000000000000000c R12: ffff9e1ea13a8800
>>>>>>>>>>> [ 47.110731] R13: 000000000000000c R14: ffff9e1ea13c0000 R15: 0000000000007530
>>>>>>>>>>> [ 47.111446] ide_transfer_pc+0x216/0x310
>>>>>>>>>>> [ 47.111848] ? __const_udelay+0x3d/0x40
>>>>>>>>>>> [ 47.112236] ? ide_execute_command+0x85/0xb0
>>>>>>>>>>> [ 47.112668] ? ide_pc_intr+0x3f0/0x3f0
>>>>>>>>>>> [ 47.113051] ? ide_check_atapi_device+0x110/0x110
>>>>>>>>>>> [ 47.113524] ide_issue_pc+0x178/0x240
>>>>>>>>>>> [ 47.113901] ide_cd_do_request+0x15c/0x350
>>>>>>>>>>> [ 47.114314] ide_queue_rq+0x180/0x6b0
>>>>>>>>>>> [ 47.114686] ? blk_mq_get_driver_tag+0xa1/0x110
>>>>>>>>>>> [ 47.115153] blk_mq_dispatch_rq_list+0x90/0x550
>>>>>>>>>>> [ 47.115606] ? __queue_delayed_work+0x63/0x90
>>>>>>>>>>> [ 47.116054] ? deadline_fifo_request+0x41/0x90
>>>>>>>>>>> [ 47.116506] blk_mq_do_dispatch_sched+0x80/0x100
>>>>>>>>>>> [ 47.116976] blk_mq_sched_dispatch_requests+0xfc/0x170
>>>>>>>>>>> [ 47.117491] __blk_mq_run_hw_queue+0x6f/0xd0
>>>>>>>>>>> [ 47.117941] blk_mq_run_work_fn+0x1b/0x20
>>>>>>>>>>> [ 47.118342] process_one_work+0x14c/0x450
>>>>>>>>>>> [ 47.118747] worker_thread+0x4a/0x440
>>>>>>>>>>> [ 47.119125] kthread+0x105/0x140
>>>>>>>>>>> [ 47.119456] ? process_one_work+0x450/0x450
>>>>>>>>>>> [ 47.119880] ? kthread_park+0x90/0x90
>>>>>>>>>>> [ 47.120251] ret_from_fork+0x35/0x40
>>>>>>>>>>> [ 47.120619] Modules linked in:
>>>>>>>>>>> [ 47.120952] ---[ end trace 4562f716e88fdefe ]---
>>>>>>>>>>> [ 47.121423] RIP: 0010:blk_mq_add_to_requeue_list+0xc1/0xd0
>>>>>>>>>>> [ 47.121981] Code: 48 8d 53 48 49 8b 8c 24 b8 04 00 00 48 89 51 08 48 89 4b 48 49 8d 8c 24 b8 04 00 00 48 89 4b 50 49 89 94 24 b8 04 00 008
>>>>>>>>>>> [ 47.123851] RSP: 0018:ffff9e1ea4b43e40 EFLAGS: 00010002
>>>>>>>>>>> [ 47.124393] RAX: ffff9e1ea13c0048 RBX: ffff9e1ea13c0000 RCX: 0000000000000006
>>>>>>>>>>> [ 47.125108] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff9e1ea13c0000
>>>>>>>>>>> [ 47.125819] RBP: ffff9e1ea4b43e68 R08: ffffeb5bcf630680 R09: 0000000000000000
>>>>>>>>>>> [ 47.126539] R10: 0000000000000001 R11: 0000000000000012 R12: ffff9e1ea1033a40
>>>>>>>>>>> [ 47.127262] R13: ffff9e1ea13a8d00 R14: ffff9e1ea13a9000 R15: 0000000000000046
>>>>>>>>>>> [ 47.127988] FS: 0000000000000000(0000) GS:ffff9e1ea4b40000(0000) knlGS:0000000000000000
>>>>>>>>>>> [ 47.128793] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>>>>>>>>> [ 47.129385] CR2: 0000003fda41fda0 CR3: 00000003d8e6a000 CR4: 00000000000006e0
>>>>>>>>>>> [ 47.130104] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>>>>>>>>>>> [ 47.130823] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>>>>>>>>>>> [ 47.131547] Kernel panic - not syncing: Fatal exception in interrupt
>>>>>>>>>>> [ 47.132609] Kernel Offset: 0x7c00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
>>>>>>>>>>> [ 47.133679] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---
>>>>>>>>>>> [ 47.134432] ------------[ cut here ]-----------
>>>>>>>>>> I’ll take a look at this, thanks for the report.
>>>>>>>>> I can't reproduce this, unfortunately. But I'm guessing it might be related
>>>>>>>>> to a race with the requeue and request handling in IDE. Can you try with
>>>>>>>>> the below patch?
>>>>>>>> Thanks for attention, but this patch doesn't help.
>>>>>>> OK, thanks for trying.
>>>>>>>
>>>>>>>> From what I reached, to reproduce it, we need to use legacy CONFIG_IDE
>>>>>>>> and friends where "ide: convert to blk-mq" sits, not CONFIG_ATA and so
>>>>>>>> on. I can reproduce it with qemux86-64 with "-drive ... if=ide" or
>>>>>>>> "-drive ... if=virtio".
>>>>>>> Yes of course, I am trying to reproduce with the legacy stack. Just not
>>>>>>> having any luck doing it, even thousands of read_all iterations on /proc
>>>>>>> with IO to the IDE drives is still not doing it. From your trace, it
>>>>>>> looks like ide-cd causing it, which would mean a cdrom of some sort.
>>>>>>>
>>>>>>> I'll try again!
>>>>>> My .config is attached.
>>>>> Can you try with this patch?
>>>> With this patch, it cannot boot up.
>>> Ugh, forgot it's inclusive. You want it at '2', not '1'.
>>
>> With "set->queue_depth = 2;", reading aganst /sys or normal disk dir is OK, but the following hang. So the related test cases are all timed out.
>>
>> ps -elf
>> ---- snip ----
>> 5 D root 415 1 0 80 0 - 664 io_sch 02:49 ttyS0 00:00:00 /opt/ltp/testcases/bin/read_all -d /proc -r 10
>> 5 D root 416 1 0 80 0 - 669 io_sch 02:49 ttyS0 00:00:00 /opt/ltp/testcases/bin/read_all -d /proc -r 10
>> 5 D root 417 1 0 80 0 - 674 io_sch 02:49 ttyS0 00:00:00 /opt/ltp/testcases/bin/read_all -d /proc -r 10
>> 5 D root 421 1 0 80 0 - 629 io_sch 02:49 ttyS0 00:00:00 /opt/ltp/testcases/bin/read_all -d /proc -r 1
>> 5 D root 434 1 0 80 0 - 629 io_sch 02:49 ttyS0 00:00:00 /opt/ltp/testcases/bin/read_all -d /proc -r 1
>> 5 D root 448 1 0 80 0 - 629 io_sch 02:55 ttyS0 00:00:00 /opt/ltp/testcases/bin/read_all -d /proc -r 1
>> 5 D root 474 1 0 80 0 - 629 flush_ 02:55 ttyS0 00:00:00 /opt/ltp/testcases/bin/read_all -d /dev -r 1
>>
>> In addition, without this change, it can be reproduced more often with more processes.
>
> I've managed to reproduce it now, though I don't quite yet see what is going
> on. It's almost like we're NOT honoring the serialization, which results
> in a sense request being doubly queued. I'll see if I can figure it out
> and produce a patch that works.

Alright, here's something that has a chance of working. I don't think we
can solve the ordering issue with sense requests without doing something
like this. Can you give it a spin?

diff --git a/drivers/ide/ide-atapi.c b/drivers/ide/ide-atapi.c
index da58020a144e..33a28cde126c 100644
--- a/drivers/ide/ide-atapi.c
+++ b/drivers/ide/ide-atapi.c
@@ -235,21 +235,28 @@ EXPORT_SYMBOL_GPL(ide_prep_sense);

int ide_queue_sense_rq(ide_drive_t *drive, void *special)
{
- struct request *sense_rq = drive->sense_rq;
+ ide_hwif_t *hwif = drive->hwif;
+ struct request *sense_rq;
+ unsigned long flags;
+
+ spin_lock_irqsave(&hwif->lock, flags);

/* deferred failure from ide_prep_sense() */
if (!drive->sense_rq_armed) {
printk(KERN_WARNING PFX "%s: error queuing a sense request\n",
drive->name);
+ spin_unlock_irqrestore(&hwif->lock, flags);
return -ENOMEM;
}

+ sense_rq = drive->sense_rq;
ide_req(sense_rq)->special = special;
drive->sense_rq_armed = false;

drive->hwif->rq = NULL;

ide_insert_request_head(drive, sense_rq);
+ spin_unlock_irqrestore(&hwif->lock, flags);
return 0;
}
EXPORT_SYMBOL_GPL(ide_queue_sense_rq);
diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
index 8445b484ae69..b137f27a34d5 100644
--- a/drivers/ide/ide-io.c
+++ b/drivers/ide/ide-io.c
@@ -68,8 +68,10 @@ int ide_end_rq(ide_drive_t *drive, struct request *rq, blk_status_t error,
}

if (!blk_update_request(rq, error, nr_bytes)) {
- if (rq == drive->sense_rq)
+ if (rq == drive->sense_rq) {
drive->sense_rq = NULL;
+ drive->sense_rq_active = false;
+ }

__blk_mq_end_request(rq, error);
return 0;
@@ -451,16 +453,11 @@ void ide_requeue_and_plug(ide_drive_t *drive, struct request *rq)
blk_mq_delay_run_hw_queue(q->queue_hw_ctx[0], 3);
}

-/*
- * Issue a new request to a device.
- */
-blk_status_t ide_queue_rq(struct blk_mq_hw_ctx *hctx,
- const struct blk_mq_queue_data *bd)
+blk_status_t ide_issue_rq(ide_drive_t *drive, struct request *rq,
+ bool local_requeue)
{
- ide_drive_t *drive = hctx->queue->queuedata;
- ide_hwif_t *hwif = drive->hwif;
+ ide_hwif_t *hwif = drive->hwif;
struct ide_host *host = hwif->host;
- struct request *rq = bd->rq;
ide_startstop_t startstop;

if (!blk_rq_is_passthrough(rq) && !(rq->rq_flags & RQF_DONTPREP)) {
@@ -474,8 +471,6 @@ blk_status_t ide_queue_rq(struct blk_mq_hw_ctx *hctx,
if (ide_lock_host(host, hwif))
return BLK_STS_DEV_RESOURCE;

- blk_mq_start_request(rq);
-
spin_lock_irq(&hwif->lock);

if (!ide_lock_port(hwif)) {
@@ -510,18 +505,6 @@ blk_status_t ide_queue_rq(struct blk_mq_hw_ctx *hctx,
hwif->cur_dev = drive;
drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);

- /*
- * we know that the queue isn't empty, but this can happen
- * if ->prep_rq() decides to kill a request
- */
- if (!rq) {
- rq = bd->rq;
- if (!rq) {
- ide_unlock_port(hwif);
- goto out;
- }
- }
-
/*
* Sanity: don't accept a request that isn't a PM request
* if we are currently power managed. This is very important as
@@ -560,9 +543,12 @@ blk_status_t ide_queue_rq(struct blk_mq_hw_ctx *hctx,
}
} else {
plug_device:
+ if (local_requeue)
+ list_add(&rq->queuelist, &drive->rq_list);
spin_unlock_irq(&hwif->lock);
ide_unlock_host(host);
- ide_requeue_and_plug(drive, rq);
+ if (!local_requeue)
+ ide_requeue_and_plug(drive, rq);
return BLK_STS_OK;
}

@@ -573,6 +559,26 @@ blk_status_t ide_queue_rq(struct blk_mq_hw_ctx *hctx,
return BLK_STS_OK;
}

+/*
+ * Issue a new request to a device.
+ */
+blk_status_t ide_queue_rq(struct blk_mq_hw_ctx *hctx,
+ const struct blk_mq_queue_data *bd)
+{
+ ide_drive_t *drive = hctx->queue->queuedata;
+ ide_hwif_t *hwif = drive->hwif;
+
+ spin_lock_irq(&hwif->lock);
+ if (drive->sense_rq_active) {
+ spin_unlock_irq(&hwif->lock);
+ return BLK_STS_DEV_RESOURCE;
+ }
+ spin_unlock_irq(&hwif->lock);
+
+ blk_mq_start_request(bd->rq);
+ return ide_issue_rq(drive, bd->rq, false);
+}
+
static int drive_is_ready(ide_drive_t *drive)
{
ide_hwif_t *hwif = drive->hwif;
@@ -893,13 +899,8 @@ EXPORT_SYMBOL_GPL(ide_pad_transfer);

void ide_insert_request_head(ide_drive_t *drive, struct request *rq)
{
- ide_hwif_t *hwif = drive->hwif;
- unsigned long flags;
-
- spin_lock_irqsave(&hwif->lock, flags);
+ drive->sense_rq_active = true;
list_add_tail(&rq->queuelist, &drive->rq_list);
- spin_unlock_irqrestore(&hwif->lock, flags);
-
kblockd_schedule_work(&drive->rq_work);
}
EXPORT_SYMBOL_GPL(ide_insert_request_head);
diff --git a/drivers/ide/ide-park.c b/drivers/ide/ide-park.c
index 102aa3bc3e7f..8af7af6001eb 100644
--- a/drivers/ide/ide-park.c
+++ b/drivers/ide/ide-park.c
@@ -54,7 +54,9 @@ static void issue_park_cmd(ide_drive_t *drive, unsigned long timeout)
scsi_req(rq)->cmd[0] = REQ_UNPARK_HEADS;
scsi_req(rq)->cmd_len = 1;
ide_req(rq)->type = ATA_PRIV_MISC;
+ spin_lock_irq(&hwif->lock);
ide_insert_request_head(drive, rq);
+ spin_unlock_irq(&hwif->lock);

out:
return;
diff --git a/drivers/ide/ide-probe.c b/drivers/ide/ide-probe.c
index 63627be0811a..5aeaca24a28f 100644
--- a/drivers/ide/ide-probe.c
+++ b/drivers/ide/ide-probe.c
@@ -1159,18 +1159,27 @@ static void drive_rq_insert_work(struct work_struct *work)
ide_drive_t *drive = container_of(work, ide_drive_t, rq_work);
ide_hwif_t *hwif = drive->hwif;
struct request *rq;
+ blk_status_t ret;
LIST_HEAD(list);

- spin_lock_irq(&hwif->lock);
- if (!list_empty(&drive->rq_list))
- list_splice_init(&drive->rq_list, &list);
- spin_unlock_irq(&hwif->lock);
+ blk_mq_quiesce_queue(drive->queue);

- while (!list_empty(&list)) {
- rq = list_first_entry(&list, struct request, queuelist);
+ ret = BLK_STS_OK;
+ spin_lock_irq(&hwif->lock);
+ while (!list_empty(&drive->rq_list)) {
+ rq = list_first_entry(&drive->rq_list, struct request, queuelist);
list_del_init(&rq->queuelist);
- blk_execute_rq_nowait(drive->queue, rq->rq_disk, rq, true, NULL);
+
+ spin_unlock_irq(&hwif->lock);
+ ret = ide_issue_rq(drive, rq, true);
+ spin_lock_irq(&hwif->lock);
}
+ spin_unlock_irq(&hwif->lock);
+
+ blk_mq_unquiesce_queue(drive->queue);
+
+ if (ret != BLK_STS_OK)
+ kblockd_schedule_work(&drive->rq_work);
}

static const u8 ide_hwif_to_major[] =
diff --git a/include/linux/ide.h b/include/linux/ide.h
index e7d29ae633cd..971cf76a78a0 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -615,6 +615,7 @@ struct ide_drive_s {

/* current sense rq and buffer */
bool sense_rq_armed;
+ bool sense_rq_active;
struct request *sense_rq;
struct request_sense sense_data;

@@ -1219,6 +1220,7 @@ extern void ide_stall_queue(ide_drive_t *drive, unsigned long timeout);
extern void ide_timer_expiry(struct timer_list *t);
extern irqreturn_t ide_intr(int irq, void *dev_id);
extern blk_status_t ide_queue_rq(struct blk_mq_hw_ctx *, const struct blk_mq_queue_data *);
+extern blk_status_t ide_issue_rq(ide_drive_t *, struct request *, bool);
extern void ide_requeue_and_plug(ide_drive_t *drive, struct request *rq);

void ide_init_disk(struct gendisk *, ide_drive_t *);

--
Jens Axboe