linux.git/block, branch v6.0.6

blk-mq: fix null pointer dereference in blk_mq_clear_rq_mapping()

2022-10-29T08:08:33+00:00

[ Upstream commit 76dd298094f484c6250ebd076fa53287477b2328 ]

Our syzkaller report a null pointer dereference, root cause is
following:

__blk_mq_alloc_map_and_rqs
 set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs
  blk_mq_alloc_map_and_rqs
   blk_mq_alloc_rqs
    // failed due to oom
    alloc_pages_node
    // set->tags[hctx_idx] is still NULL
    blk_mq_free_rqs
     drv_tags = set->tags[hctx_idx];
     // null pointer dereference is triggered
     blk_mq_clear_rq_mapping(drv_tags, ...)

This is because commit 63064be150e4 ("blk-mq:
Add blk_mq_alloc_map_and_rqs()") merged the two steps:

1) set->tags[hctx_idx] = blk_mq_alloc_rq_map()
2) blk_mq_alloc_rqs(..., set->tags[hctx_idx])

into one step:

set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs()

Since tags is not initialized yet in this case, fix the problem by
checking if tags is NULL pointer in blk_mq_clear_rq_mapping().

Fixes: 63064be150e4 ("blk-mq: Add blk_mq_alloc_map_and_rqs()")
Signed-off-by: Yu Kuai 
Reviewed-by: John Garry 
Link: https://lore.kernel.org/r/20221011142253.4015966-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

blk-wbt: fix that 'rwb->wc' is always set to 1 in wbt_init()

2022-10-21T10:39:28+00:00

commit 285febabac4a16655372d23ff43e89ff6f216691 upstream.

commit 8c5035dfbb94 ("blk-wbt: call rq_qos_add() after wb_normal is
initialized") moves wbt_set_write_cache() before rq_qos_add(), which
is wrong because wbt_rq_qos() is still NULL.

Fix the problem by removing wbt_set_write_cache() and setting 'rwb->wc'
directly. Noted that this patch also remove the redundant setting of
'rab->wc'.

Fixes: 8c5035dfbb94 ("blk-wbt: call rq_qos_add() after wb_normal is initialized")
Reported-by: kernel test robot 
Link: https://lore.kernel.org/r/202210081045.77ddf59b-yujie.liu@intel.com
Signed-off-by: Yu Kuai 
Reviewed-by: Ming Lei 
Link: https://lore.kernel.org/r/20221009101038.1692875-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

blk-mq: use quiesced elevator switch when reinitializing queues

2022-10-21T10:39:25+00:00

[ Upstream commit 8237c01f1696bc53c470493bf1fe092a107648a6 ]

The hctx's run_work may be racing with the elevator switch when
reinitializing hardware queues. The queue is merely frozen in this
context, but that only prevents requests from allocating and doesn't
stop the hctx work from running. The work may get an elevator pointer
that's being torn down, and can result in use-after-free errors and
kernel panics (example below). Use the quiesced elevator switch instead,
and make the previous one static since it is now only used locally.

  nvme nvme0: resetting controller
  nvme nvme0: 32/0/0 default/read/poll queues
  BUG: kernel NULL pointer dereference, address: 0000000000000008
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 80000020c8861067 P4D 80000020c8861067 PUD 250f8c8067 PMD 0
  Oops: 0000 [#1] SMP PTI
  Workqueue: kblockd blk_mq_run_work_fn
  RIP: 0010:kyber_has_work+0x29/0x70

...

  Call Trace:
   __blk_mq_do_dispatch_sched+0x83/0x2b0
   __blk_mq_sched_dispatch_requests+0x12e/0x170
   blk_mq_sched_dispatch_requests+0x30/0x60
   __blk_mq_run_hw_queue+0x2b/0x50
   process_one_work+0x1ef/0x380
   worker_thread+0x2d/0x3e0

Signed-off-by: Keith Busch 
Reviewed-by: Ming Lei 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20220927155652.3260724-1-kbusch@fb.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

blk-throttle: prevent overflow while calculating wait time

2022-10-21T10:39:22+00:00

[ Upstream commit 8d6bbaada2e0a65f9012ac4c2506460160e7237a ]

There is a problem found by code review in tg_with_in_bps_limit() that
'bps_limit * jiffy_elapsed_rnd' might overflow. Fix the problem by
calling mul_u64_u64_div_u64() instead.

Signed-off-by: Yu Kuai 
Acked-by: Tejun Heo 
Link: https://lore.kernel.org/r/20220829022240.3348319-3-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

blk-wbt: call rq_qos_add() after wb_normal is initialized

2022-10-21T10:37:54+00:00

commit 8c5035dfbb9475b67c82b3fdb7351236525bf52b upstream.

Our test found a problem that wbt inflight counter is negative, which
will cause io hang(noted that this problem doesn't exist in mainline):

t1: device create	t2: issue io
add_disk
 blk_register_queue
  wbt_enable_default
   wbt_init
    rq_qos_add
    // wb_normal is still 0
			/*
			 * in mainline, disk can't be opened before
			 * bdev_add(), however, in old kernels, disk
			 * can be opened before blk_register_queue().
			 */
			blkdev_issue_flush
                        // disk size is 0, however, it's not checked
                         submit_bio_wait
                          submit_bio
                           blk_mq_submit_bio
                            rq_qos_throttle
                             wbt_wait
			      bio_to_wbt_flags
                               rwb_enabled
			       // wb_normal is 0, inflight is not increased

    wbt_queue_depth_changed(&rwb->rqos);
     wbt_update_limits
     // wb_normal is initialized
                            rq_qos_track
                             wbt_track
                              rq->wbt_flags |= bio_to_wbt_flags(rwb, bio);
			      // wb_normal is not 0，wbt_flags will be set
t3: io completion
blk_mq_free_request
 rq_qos_done
  wbt_done
   wbt_is_tracked
   // return true
   __wbt_done
    wbt_rqw_done
     atomic_dec_return(&rqw->inflight);
     // inflight is decreased

commit 8235b5c1e8c1 ("block: call bdev_add later in device_add_disk") can
avoid this problem, however it's better to fix this problem in wbt:

1) Lower kernel can't backport this patch due to lots of refactor.
2) Root cause is that wbt call rq_qos_add() before wb_normal is
initialized.

Fixes: e34cbd307477 ("blk-wbt: add general throttling mechanism")
Cc: 
Signed-off-by: Yu Kuai 
Link: https://lore.kernel.org/r/20220913105749.3086243-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

blk-throttle: fix that io throttle can only work for single bio

2022-10-21T10:37:54+00:00

commit 320fb0f91e55ba248d4bad106b408e59099cfa89 upstream.

Test scripts:
cd /sys/fs/cgroup/blkio/
echo "8:0 1024" > blkio.throttle.write_bps_device
echo $$ > cgroup.procs
dd if=/dev/zero of=/dev/sda bs=10k count=1 oflag=direct &
dd if=/dev/zero of=/dev/sda bs=10k count=1 oflag=direct &

Test result:
10240 bytes (10 kB, 10 KiB) copied, 10.0134 s, 1.0 kB/s
10240 bytes (10 kB, 10 KiB) copied, 10.0135 s, 1.0 kB/s

The problem is that the second bio is finished after 10s instead of 20s.

Root cause:
1) second bio will be flagged:

__blk_throtl_bio
 while (true) {
  ...
  if (sq->nr_queued[rw]) -> some bio is throttled already
   break
 };
 bio_set_flag(bio, BIO_THROTTLED); -> flag the bio

2) flagged bio will be dispatched without waiting:

throtl_dispatch_tg
 tg_may_dispatch
  tg_with_in_bps_limit
   if (bps_limit == U64_MAX || bio_flagged(bio, BIO_THROTTLED))
    *wait = 0; -> wait time is zero
    return true;

commit 9f5ede3c01f9 ("block: throttle split bio in case of iops limit")
support to count split bios for iops limit, thus it adds flagged bio
checking in tg_with_in_bps_limit() so that split bios will only count
once for bps limit, however, it introduce a new problem that io throttle
won't work if multiple bios are throttled.

In order to fix the problem, handle iops/bps limit in different ways:

1) for iops limit, there is no flag to record if the bio is throttled,
   and iops is always applied.
2) for bps limit, original bio will be flagged with BIO_BPS_THROTTLED,
   and io throttle will ignore bio with the flag.

Noted this patch also remove the code to set flag in __bio_clone(), it's
introduced in commit 111be8839817 ("block-throttle: avoid double
charge"), and author thinks split bio can be resubmited and throttled
again, which is wrong because split bio will continue to dispatch from
caller.

Fixes: 9f5ede3c01f9 ("block: throttle split bio in case of iops limit")
Cc: 
Signed-off-by: Yu Kuai 
Acked-by: Tejun Heo 
Link: https://lore.kernel.org/r/20220829022240.3348319-2-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'block-6.0-2022-09-22' of git://git.kernel.dk/linux

2022-09-24T15:22:53+00:00

Pull block fixes from Jens Axboe:
 "Fix a regression that's been plaguing us by reverting the offending
  commit, as attempts to both reproduce the issue and fix it in a saner
  fashion have failed.

  Fix for a potential oops condition in the s390 dasd block driver"

* tag 'block-6.0-2022-09-22' of git://git.kernel.dk/linux:
  Revert "block: freeze the queue earlier in del_gendisk"
  s390/dasd: fix Oops in dasd_alias_get_start_dev due to missing pavgroup

Revert "block: freeze the queue earlier in del_gendisk"

2022-09-20T14:15:44+00:00

This reverts commit a09b314005f3a0956ebf56e01b3b80339df577cc.

Dusty Mabe reported consistent hang during CoreOS shutdown with a MD
RAID1 setup.  Although apparently similar hangs happened before,
and this patch most likely is not the root cause it made it much
more severe.  Revert it until we can figure out what is going on
with the md driver.

Signed-off-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20220919144049.978907-1-hch@lst.de
Signed-off-by: Jens Axboe

Merge tag 'block-6.0-2022-09-16' of git://git.kernel.dk/linux-block

2022-09-16T13:58:04+00:00

Pull block fixes from Jens Axboe:
 "Two fixes for -rc6:

   - Fix a mixup of sectors and bytes in the secure erase ioctl
     (Mikulas)

   - Fix for a bad return value for a non-blocking bio/blk queue enter
     call (me)"

* tag 'block-6.0-2022-09-16' of git://git.kernel.dk/linux-block:
  blk-lib: fix blkdev_issue_secure_erase
  block: blk_queue_enter() / __bio_queue_enter() must return -EAGAIN for nowait

blk-lib: fix blkdev_issue_secure_erase

2022-09-15T06:25:17+00:00

There's a bug in blkdev_issue_secure_erase. The statement
"unsigned int len = min_t(sector_t, nr_sects, max_sectors);"
sets the variable "len" to the length in sectors, but the statement
"bio->bi_iter.bi_size = len" treats it as if it were in bytes.
The statements "sector += len << SECTOR_SHIFT" and "nr_sects -= len <<
SECTOR_SHIFT" are thinko.

This patch fixes it.

Signed-off-by: Mikulas Patocka 
Cc: stable@vger.kernel.org	# v5.19
Fixes: 44abff2c0b97 ("block: decouple REQ_OP_SECURE_ERASE from REQ_OP_DISCARD")
Link: https://lore.kernel.org/r/alpine.LRH.2.02.2209141549480.28100@file01.intranet.prod.int.rdu2.redhat.com
Signed-off-by: Jens Axboe