linux-stable.git/block, branch v5.6.8

block: fix busy device checking in blk_drop_partitions again

2020-04-29T14:34:35+00:00

[ Upstream commit cb6b771b05c3026a85ed4817c1b87c5e6f41d136 ]

The previous fix had an off by one in the bd_openers checking, counting
the callers blkdev_get.

Fixes: d3ef5536274f ("block: fix busy device checking in blk_drop_partitions")
Reported-by: Qian Cai 
Signed-off-by: Christoph Hellwig 
Tested-by: Qian Cai 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: fix busy device checking in blk_drop_partitions

2020-04-29T14:34:32+00:00

[ Upstream commit d3ef5536274faf89e626276b833be122a16bdb81 ]

bd_super is only set by get_tree_bdev and mount_bdev, and thus not by
other openers like btrfs or the XFS realtime and log devices, as well as
block devices directly opened from user space.  Check bd_openers
instead.

Fixes: 77032ca66f86 ("Return EBUSY from BLKRRPART for mounted whole-dev fs")
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block, bfq: invoke flush_idle_tree after reparent_active_queues in pd_offline

2020-04-23T08:37:58+00:00

commit 4d38a87fbb77fb9ff2ff4e914162a8ae6453eff5 upstream.

In bfq_pd_offline(), the function bfq_flush_idle_tree() is invoked to
flush the rb tree that contains all idle entities belonging to the pd
(cgroup) being destroyed. In particular, bfq_flush_idle_tree() is
invoked before bfq_reparent_active_queues(). Yet the latter may happen
to add some entities to the idle tree. It happens if, in some of the
calls to bfq_bfqq_move() performed by bfq_reparent_active_queues(),
the queue to move is empty and gets expired.

This commit simply reverses the invocation order between
bfq_flush_idle_tree() and bfq_reparent_active_queues().

Tested-by: cki-project@redhat.com
Signed-off-by: Paolo Valente 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block, bfq: make reparent_leaf_entity actually work only on leaf entities

2020-04-23T08:37:57+00:00

commit 576682fa52cbd95deb3773449566274f206acc58 upstream.

bfq_reparent_leaf_entity() reparents the input leaf entity (a leaf
entity represents just a bfq_queue in an entity tree). Yet, the input
entity is guaranteed to always be a leaf entity only in two-level
entity trees. In this respect, because of the error fixed by
commit 14afc5936197 ("block, bfq: fix overwrite of bfq_group pointer
in bfq_find_set_group()"), all (wrongly collapsed) entity trees happened
to actually have only two levels. After the latter commit, this does not
hold any longer.

This commit fixes this problem by modifying
bfq_reparent_leaf_entity(), so that it searches an active leaf entity
down the path that stems from the input entity. Such a leaf entity is
guaranteed to exist when bfq_reparent_leaf_entity() is invoked.

Tested-by: cki-project@redhat.com
Signed-off-by: Paolo Valente 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block, bfq: turn put_queue into release_process_ref in __bfq_bic_change_cgroup

2020-04-23T08:37:57+00:00

commit c8997736650060594845e42c5d01d3118aec8d25 upstream.

A bfq_put_queue() may be invoked in __bfq_bic_change_cgroup(). The
goal of this put is to release a process reference to a bfq_queue. But
process-reference releases may trigger also some extra operation, and,
to this goal, are handled through bfq_release_process_ref(). So, turn
the invocation of bfq_put_queue() into an invocation of
bfq_release_process_ref().

Tested-by: cki-project@redhat.com
Signed-off-by: Paolo Valente 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block, bfq: fix use-after-free in bfq_idle_slice_timer_body

2020-04-17T14:13:23+00:00

[ Upstream commit 2f95fa5c955d0a9987ffdc3a095e2f4e62c5f2a9 ]

In bfq_idle_slice_timer func, bfqq = bfqd->in_service_queue is
not in bfqd-lock critical section. The bfqq, which is not
equal to NULL in bfq_idle_slice_timer, may be freed after passing
to bfq_idle_slice_timer_body. So we will access the freed memory.

In addition, considering the bfqq may be in race, we should
firstly check whether bfqq is in service before doing something
on it in bfq_idle_slice_timer_body func. If the bfqq in race is
not in service, it means the bfqq has been expired through
__bfq_bfqq_expire func, and wait_request flags has been cleared in
__bfq_bfqd_reset_in_service func. So we do not need to re-clear the
wait_request of bfqq which is not in service.

KASAN log is given as follows:
[13058.354613] ==================================================================
[13058.354640] BUG: KASAN: use-after-free in bfq_idle_slice_timer+0xac/0x290
[13058.354644] Read of size 8 at addr ffffa02cf3e63f78 by task fork13/19767
[13058.354646]
[13058.354655] CPU: 96 PID: 19767 Comm: fork13
[13058.354661] Call trace:
[13058.354667]  dump_backtrace+0x0/0x310
[13058.354672]  show_stack+0x28/0x38
[13058.354681]  dump_stack+0xd8/0x108
[13058.354687]  print_address_description+0x68/0x2d0
[13058.354690]  kasan_report+0x124/0x2e0
[13058.354697]  __asan_load8+0x88/0xb0
[13058.354702]  bfq_idle_slice_timer+0xac/0x290
[13058.354707]  __hrtimer_run_queues+0x298/0x8b8
[13058.354710]  hrtimer_interrupt+0x1b8/0x678
[13058.354716]  arch_timer_handler_phys+0x4c/0x78
[13058.354722]  handle_percpu_devid_irq+0xf0/0x558
[13058.354731]  generic_handle_irq+0x50/0x70
[13058.354735]  __handle_domain_irq+0x94/0x110
[13058.354739]  gic_handle_irq+0x8c/0x1b0
[13058.354742]  el1_irq+0xb8/0x140
[13058.354748]  do_wp_page+0x260/0xe28
[13058.354752]  __handle_mm_fault+0x8ec/0x9b0
[13058.354756]  handle_mm_fault+0x280/0x460
[13058.354762]  do_page_fault+0x3ec/0x890
[13058.354765]  do_mem_abort+0xc0/0x1b0
[13058.354768]  el0_da+0x24/0x28
[13058.354770]
[13058.354773] Allocated by task 19731:
[13058.354780]  kasan_kmalloc+0xe0/0x190
[13058.354784]  kasan_slab_alloc+0x14/0x20
[13058.354788]  kmem_cache_alloc_node+0x130/0x440
[13058.354793]  bfq_get_queue+0x138/0x858
[13058.354797]  bfq_get_bfqq_handle_split+0xd4/0x328
[13058.354801]  bfq_init_rq+0x1f4/0x1180
[13058.354806]  bfq_insert_requests+0x264/0x1c98
[13058.354811]  blk_mq_sched_insert_requests+0x1c4/0x488
[13058.354818]  blk_mq_flush_plug_list+0x2d4/0x6e0
[13058.354826]  blk_flush_plug_list+0x230/0x548
[13058.354830]  blk_finish_plug+0x60/0x80
[13058.354838]  read_pages+0xec/0x2c0
[13058.354842]  __do_page_cache_readahead+0x374/0x438
[13058.354846]  ondemand_readahead+0x24c/0x6b0
[13058.354851]  page_cache_sync_readahead+0x17c/0x2f8
[13058.354858]  generic_file_buffered_read+0x588/0xc58
[13058.354862]  generic_file_read_iter+0x1b4/0x278
[13058.354965]  ext4_file_read_iter+0xa8/0x1d8 [ext4]
[13058.354972]  __vfs_read+0x238/0x320
[13058.354976]  vfs_read+0xbc/0x1c0
[13058.354980]  ksys_read+0xdc/0x1b8
[13058.354984]  __arm64_sys_read+0x50/0x60
[13058.354990]  el0_svc_common+0xb4/0x1d8
[13058.354994]  el0_svc_handler+0x50/0xa8
[13058.354998]  el0_svc+0x8/0xc
[13058.354999]
[13058.355001] Freed by task 19731:
[13058.355007]  __kasan_slab_free+0x120/0x228
[13058.355010]  kasan_slab_free+0x10/0x18
[13058.355014]  kmem_cache_free+0x288/0x3f0
[13058.355018]  bfq_put_queue+0x134/0x208
[13058.355022]  bfq_exit_icq_bfqq+0x164/0x348
[13058.355026]  bfq_exit_icq+0x28/0x40
[13058.355030]  ioc_exit_icq+0xa0/0x150
[13058.355035]  put_io_context_active+0x250/0x438
[13058.355038]  exit_io_context+0xd0/0x138
[13058.355045]  do_exit+0x734/0xc58
[13058.355050]  do_group_exit+0x78/0x220
[13058.355054]  __wake_up_parent+0x0/0x50
[13058.355058]  el0_svc_common+0xb4/0x1d8
[13058.355062]  el0_svc_handler+0x50/0xa8
[13058.355066]  el0_svc+0x8/0xc
[13058.355067]
[13058.355071] The buggy address belongs to the object at ffffa02cf3e63e70#012 which belongs to the cache bfq_queue of size 464
[13058.355075] The buggy address is located 264 bytes inside of#012 464-byte region [ffffa02cf3e63e70, ffffa02cf3e64040)
[13058.355077] The buggy address belongs to the page:
[13058.355083] page:ffff7e80b3cf9800 count:1 mapcount:0 mapping:ffff802db5c90780 index:0xffffa02cf3e606f0 compound_mapcount: 0
[13058.366175] flags: 0x2ffffe0000008100(slab|head)
[13058.370781] raw: 2ffffe0000008100 ffff7e80b53b1408 ffffa02d730c1c90 ffff802db5c90780
[13058.370787] raw: ffffa02cf3e606f0 0000000000370023 00000001ffffffff 0000000000000000
[13058.370789] page dumped because: kasan: bad access detected
[13058.370791]
[13058.370792] Memory state around the buggy address:
[13058.370797]  ffffa02cf3e63e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fb fb
[13058.370801]  ffffa02cf3e63e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[13058.370805] >ffffa02cf3e63f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[13058.370808]                                                                 ^
[13058.370811]  ffffa02cf3e63f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[13058.370815]  ffffa02cf3e64000: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
[13058.370817] ==================================================================
[13058.370820] Disabling lock debugging due to kernel taint

Here, we directly pass the bfqd to bfq_idle_slice_timer_body func.
--
V2->V3: rewrite the comment as suggested by Paolo Valente
V1->V2: add one comment, and add Fixes and Reported-by tag.

Fixes: aee69d78d ("block, bfq: introduce the BFQ-v0 I/O scheduler as an extra scheduler")
Acked-by: Paolo Valente 
Reported-by: Wang Wang 
Signed-off-by: Zhiqiang Liu 
Signed-off-by: Feilong Lin 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block, zoned: fix integer overflow with BLKRESETZONE et al

2020-04-17T14:13:22+00:00

[ Upstream commit 11bde986002c0af67eb92d73321d06baefae7128 ]

Check for overflow in addition before checking for end-of-block-device.

Steps to reproduce:

	#define _GNU_SOURCE 1
	#include 
	#include 
	#include 
	#include 

	typedef unsigned long long __u64;

	struct blk_zone_range {
	        __u64 sector;
	        __u64 nr_sectors;
	};

	#define BLKRESETZONE    _IOW(0x12, 131, struct blk_zone_range)

	int main(void)
	{
	        int fd = open("/dev/nullb0", O_RDWR|O_DIRECT);
	        struct blk_zone_range zr = {4096, 0xfffffffffffff000ULL};
	        ioctl(fd, BLKRESETZONE, &zr);
	        return 0;
	}

BUG: KASAN: null-ptr-deref in submit_bio_wait+0x74/0xe0
Write of size 8 at addr 0000000000000040 by task a.out/1590

CPU: 8 PID: 1590 Comm: a.out Not tainted 5.6.0-rc1-00019-g359c92c02bfa #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190711_202441-buildvm-armv7-10.arm.fedoraproject.org-2.fc31 04/01/2014
Call Trace:
 dump_stack+0x76/0xa0
 __kasan_report.cold+0x5/0x3e
 kasan_report+0xe/0x20
 submit_bio_wait+0x74/0xe0
 blkdev_zone_mgmt+0x26f/0x2a0
 blkdev_zone_mgmt_ioctl+0x14b/0x1b0
 blkdev_ioctl+0xb28/0xe60
 block_ioctl+0x69/0x80
 ksys_ioctl+0x3af/0xa50

Reviewed-by: Christoph Hellwig 
Signed-off-by: Alexey Dobriyan (SK hynix) 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: Fix use-after-free issue accessing struct io_cq

2020-04-17T14:13:22+00:00

[ Upstream commit 30a2da7b7e225ef6c87a660419ea04d3cef3f6a7 ]

There is a potential race between ioc_release_fn() and
ioc_clear_queue() as shown below, due to which below kernel
crash is observed. It also can result into use-after-free
issue.

context#1:				context#2:
ioc_release_fn()			__ioc_clear_queue() gets the same icq
->spin_lock(&ioc->lock);		->spin_lock(&ioc->lock);
->ioc_destroy_icq(icq);
  ->list_del_init(&icq->q_node);
  ->call_rcu(&icq->__rcu_head,
  	icq_free_icq_rcu);
->spin_unlock(&ioc->lock);
					->ioc_destroy_icq(icq);
					  ->hlist_del_init(&icq->ioc_node);
					  This results into below crash as this memory
					  is now used by icq->__rcu_head in context#1.
					  There is a chance that icq could be free'd
					  as well.

22150.386550:   <6> Unable to handle kernel write to read-only memory
at virtual address ffffffaa8d31ca50
...
Call trace:
22150.607350:   <2>  ioc_destroy_icq+0x44/0x110
22150.611202:   <2>  ioc_clear_queue+0xac/0x148
22150.615056:   <2>  blk_cleanup_queue+0x11c/0x1a0
22150.619174:   <2>  __scsi_remove_device+0xdc/0x128
22150.623465:   <2>  scsi_forget_host+0x2c/0x78
22150.627315:   <2>  scsi_remove_host+0x7c/0x2a0
22150.631257:   <2>  usb_stor_disconnect+0x74/0xc8
22150.635371:   <2>  usb_unbind_interface+0xc8/0x278
22150.639665:   <2>  device_release_driver_internal+0x198/0x250
22150.644897:   <2>  device_release_driver+0x24/0x30
22150.649176:   <2>  bus_remove_device+0xec/0x140
22150.653204:   <2>  device_del+0x270/0x460
22150.656712:   <2>  usb_disable_device+0x120/0x390
22150.660918:   <2>  usb_disconnect+0xf4/0x2e0
22150.664684:   <2>  hub_event+0xd70/0x17e8
22150.668197:   <2>  process_one_work+0x210/0x480
22150.672222:   <2>  worker_thread+0x32c/0x4c8

Fix this by adding a new ICQ_DESTROYED flag in ioc_destroy_icq() to
indicate this icq is once marked as destroyed. Also, ensure
__ioc_clear_queue() is accessing icq within rcu_read_lock/unlock so
that icq doesn't get free'd up while it is still using it.

Signed-off-by: Sahitya Tummala 
Co-developed-by: Pradeep P V K 
Signed-off-by: Pradeep P V K 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block, bfq: move forward the getting of an extra ref in bfq_bfqq_move

2020-04-17T14:13:20+00:00

[ Upstream commit fd1bb3ae54a9a2e0c42709de861c69aa146b8955 ]

Commit ecedd3d7e199 ("block, bfq: get extra ref to prevent a queue
from being freed during a group move") gets an extra reference to a
bfq_queue before possibly deactivating it (temporarily), in
bfq_bfqq_move(). This prevents the bfq_queue from disappearing before
being reactivated in its new group.

Yet, the bfq_queue may also be expired (i.e., its service may be
stopped) before the bfq_queue is deactivated. And also an expiration
may lead to a premature freeing. This commit fixes this issue by
simply moving forward the getting of the extra reference already
introduced by commit ecedd3d7e199 ("block, bfq: get extra ref to
prevent a queue from being freed during a group move").

Reported-by: cki-project@redhat.com
Tested-by: cki-project@redhat.com
Signed-off-by: Paolo Valente 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: keep bdi->io_pages in sync with max_sectors_kb for stacked devices

2020-04-17T14:13:19+00:00

[ Upstream commit e74d93e96d721c4297f2a900ad0191890d2fc2b0 ]

Field bdi->io_pages added in commit 9491ae4aade6 ("mm: don't cap request
size based on read-ahead setting") removes unneeded split of read requests.

Stacked drivers do not call blk_queue_max_hw_sectors(). Instead they set
limits of their devices by blk_set_stacking_limits() + disk_stack_limits().
Field bio->io_pages stays zero until user set max_sectors_kb via sysfs.

This patch updates io_pages after merging limits in disk_stack_limits().

Commit c6d6e9b0f6b4 ("dm: do not allow readahead to limit IO size") fixed
the same problem for device-mapper devices, this one fixes MD RAIDs.

Fixes: 9491ae4aade6 ("mm: don't cap request size based on read-ahead setting")
Reviewed-by: Paul Menzel 
Reviewed-by: Bob Liu 
Signed-off-by: Konstantin Khlebnikov 
Signed-off-by: Song Liu 
Signed-off-by: Sasha Levin