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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Ming Lei <ming.lei@redhat.com>, Yi Zhang <yi.zhang@redhat.com>,
	Bart Van Assche <bvanassche@acm.org>,
	Jens Axboe <axboe@kernel.dk>, Sasha Levin <sashal@kernel.org>,
	linux-block@vger.kernel.org
Subject: [PATCH AUTOSEL 5.13 29/59] block: fix race between adding/removing rq qos and normal IO
Date: Mon,  5 Jul 2021 11:27:45 -0400	[thread overview]
Message-ID: <20210705152815.1520546-29-sashal@kernel.org> (raw)
In-Reply-To: <20210705152815.1520546-1-sashal@kernel.org>

From: Ming Lei <ming.lei@redhat.com>

[ Upstream commit 2cafe29a8d03f02a3d16193bdaae2f3e82a423f9 ]

Yi reported several kernel panics on:

[16687.001777] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008
...
[16687.163549] pc : __rq_qos_track+0x38/0x60

or

[  997.690455] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020
...
[  997.850347] pc : __rq_qos_done+0x2c/0x50

Turns out it is caused by race between adding rq qos(wbt) and normal IO
because rq_qos_add can be run when IO is being submitted, fix this issue
by freezing queue before adding/deleting rq qos to queue.

rq_qos_exit() needn't to freeze queue because it is called after queue
has been frozen.

iolatency calls rq_qos_add() during allocating queue, so freezing won't
add delay because queue usage refcount works at atomic mode at that
time.

iocost calls rq_qos_add() when writing cgroup attribute file, that is
fine to freeze queue at that time since we usually freeze queue when
storing to queue sysfs attribute, meantime iocost only exists on the
root cgroup.

wbt_init calls it in blk_register_queue() and queue sysfs attribute
store(queue_wb_lat_store() when write it 1st time in case of !BLK_WBT_MQ),
the following patch will speedup the queue freezing in wbt_init.

Reported-by: Yi Zhang <yi.zhang@redhat.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Link: https://lore.kernel.org/r/20210609015822.103433-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 block/blk-rq-qos.h | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h
index 2bc43e94f4c4..2bcb3495e376 100644
--- a/block/blk-rq-qos.h
+++ b/block/blk-rq-qos.h
@@ -7,6 +7,7 @@
 #include <linux/blk_types.h>
 #include <linux/atomic.h>
 #include <linux/wait.h>
+#include <linux/blk-mq.h>
 
 #include "blk-mq-debugfs.h"
 
@@ -99,8 +100,21 @@ static inline void rq_wait_init(struct rq_wait *rq_wait)
 
 static inline void rq_qos_add(struct request_queue *q, struct rq_qos *rqos)
 {
+	/*
+	 * No IO can be in-flight when adding rqos, so freeze queue, which
+	 * is fine since we only support rq_qos for blk-mq queue.
+	 *
+	 * Reuse ->queue_lock for protecting against other concurrent
+	 * rq_qos adding/deleting
+	 */
+	blk_mq_freeze_queue(q);
+
+	spin_lock_irq(&q->queue_lock);
 	rqos->next = q->rq_qos;
 	q->rq_qos = rqos;
+	spin_unlock_irq(&q->queue_lock);
+
+	blk_mq_unfreeze_queue(q);
 
 	if (rqos->ops->debugfs_attrs)
 		blk_mq_debugfs_register_rqos(rqos);
@@ -110,12 +124,22 @@ static inline void rq_qos_del(struct request_queue *q, struct rq_qos *rqos)
 {
 	struct rq_qos **cur;
 
+	/*
+	 * See comment in rq_qos_add() about freezing queue & using
+	 * ->queue_lock.
+	 */
+	blk_mq_freeze_queue(q);
+
+	spin_lock_irq(&q->queue_lock);
 	for (cur = &q->rq_qos; *cur; cur = &(*cur)->next) {
 		if (*cur == rqos) {
 			*cur = rqos->next;
 			break;
 		}
 	}
+	spin_unlock_irq(&q->queue_lock);
+
+	blk_mq_unfreeze_queue(q);
 
 	blk_mq_debugfs_unregister_rqos(rqos);
 }
-- 
2.30.2


  parent reply	other threads:[~2021-07-05 15:29 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-05 15:27 [PATCH AUTOSEL 5.13 01/59] HID: do not use down_interruptible() when unbinding devices Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 02/59] EDAC/ti: Add missing MODULE_DEVICE_TABLE Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 03/59] ACPI: PM: s2idle: Add missing LPS0 functions for AMD Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 04/59] ACPI: scan: Rearrange dep_unmet initialization Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 05/59] ACPI: processor idle: Fix up C-state latency if not ordered Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 06/59] hv_utils: Fix passing zero to 'PTR_ERR' warning Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 07/59] lib: vsprintf: Fix handling of number field widths in vsscanf Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 08/59] Input: goodix - platform/x86: touchscreen_dmi - Move upside down quirks to touchscreen_dmi.c Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 09/59] platform/x86: touchscreen_dmi: Add an extra entry for the upside down Goodix touchscreen on Teclast X89 tablets Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 10/59] platform/x86: touchscreen_dmi: Add info for the Goodix GT912 panel of TM800A550L tablets Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 11/59] ACPI: EC: Make more Asus laptops use ECDT _GPE Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 12/59] block_dump: remove block_dump feature in mark_inode_dirty() Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 13/59] blk-mq: grab rq->refcount before calling ->fn in blk_mq_tagset_busy_iter Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 14/59] blk-mq: clear stale request in tags->rq[] before freeing one request pool Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 15/59] fs: dlm: fix srcu read lock usage Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 16/59] fs: dlm: reconnect if socket error report occurs Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 17/59] fs: dlm: cancel work sync othercon Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 18/59] fs: dlm: fix connection tcp EOF handling Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 19/59] random32: Fix implicit truncation warning in prandom_seed_state() Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 20/59] open: don't silently ignore unknown O-flags in openat2() Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 21/59] drivers: hv: Fix missing error code in vmbus_connect() Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 22/59] fs: dlm: fix lowcomms_start error case Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 23/59] fs: dlm: fix memory leak when fenced Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 24/59] ACPICA: Fix memory leak caused by _CID repair function Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 25/59] ACPI: bus: Call kobject_put() in acpi_init() error path Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 26/59] ACPI: resources: Add checks for ACPI IRQ override Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 27/59] HID: hid-input: add Surface Go battery quirk Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 28/59] HID: sony: fix freeze when inserting ghlive ps3/wii dongles Sasha Levin
2021-07-05 15:27 ` Sasha Levin [this message]
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 30/59] platform/x86: asus-nb-wmi: Revert "Drop duplicate DMI quirk structures" Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 31/59] platform/x86: asus-nb-wmi: Revert "add support for ASUS ROG Zephyrus G14 and G15" Sasha Levin
2021-07-05 17:08   ` Hans de Goede
2021-07-05 17:09     ` Hans de Goede
2021-07-09 22:50       ` Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 32/59] platform/x86: toshiba_acpi: Fix missing error code in toshiba_acpi_setup_keyboard() Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 33/59] nvme-pci: fix var. type for increasing cq_head Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 34/59] nvmet-fc: do not check for invalid target port in nvmet_fc_handle_fcp_rqst() Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 35/59] EDAC/Intel: Do not load EDAC driver when running as a guest Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 36/59] tools/power/x86/intel-speed-select: Fix uncore memory frequency display Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 37/59] PCI: hv: Add check for hyperv_initialized in init_hv_pci_drv() Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 38/59] cifs: improve fallocate emulation Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 39/59] cifs: fix check of dfs interlinks Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 40/59] cifs: retry lookup and readdir when EAGAIN is returned Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 41/59] smb3: fix uninitialized value for port in witness protocol move Sasha Levin
2021-07-05 15:27 ` [PATCH AUTOSEL 5.13 42/59] cifs: fix SMB1 error path in cifs_get_file_info_unix Sasha Levin

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