Commit graph

342 commits

Author SHA1 Message Date
Linus Torvalds
cb690f5238 for-5.16/drivers-2021-11-09
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Merge tag 'for-5.16/drivers-2021-11-09' of git://git.kernel.dk/linux-block

Pull more block driver updates from Jens Axboe:

 - Last series adding error handling support for add_disk() in drivers.
   After this one, and once the SCSI side has been merged, we can
   finally annotate add_disk() as must_check. (Luis)

 - bcache fixes (Coly)

 - zram fixes (Ming)

 - ataflop locking fix (Tetsuo)

 - nbd fixes (Ye, Yu)

 - MD merge via Song
      - Cleanup (Yang)
      - sysfs fix (Guoqing)

 - Misc fixes (Geert, Wu, luo)

* tag 'for-5.16/drivers-2021-11-09' of git://git.kernel.dk/linux-block: (34 commits)
  bcache: Revert "bcache: use bvec_virt"
  ataflop: Add missing semicolon to return statement
  floppy: address add_disk() error handling on probe
  ataflop: address add_disk() error handling on probe
  block: update __register_blkdev() probe documentation
  ataflop: remove ataflop_probe_lock mutex
  mtd/ubi/block: add error handling support for add_disk()
  block/sunvdc: add error handling support for add_disk()
  z2ram: add error handling support for add_disk()
  nvdimm/pmem: use add_disk() error handling
  nvdimm/pmem: cleanup the disk if pmem_release_disk() is yet assigned
  nvdimm/blk: add error handling support for add_disk()
  nvdimm/blk: avoid calling del_gendisk() on early failures
  nvdimm/btt: add error handling support for add_disk()
  nvdimm/btt: use goto error labels on btt_blk_init()
  loop: Remove duplicate assignments
  drbd: Fix double free problem in drbd_create_device
  nvdimm/btt: do not call del_gendisk() if not needed
  bcache: fix use-after-free problem in bcache_device_free()
  zram: replace fsync_bdev with sync_blockdev
  ...
2021-11-09 11:24:08 -08:00
Yu Kuai
494dbee341 nbd: error out if socket index doesn't match in nbd_handle_reply()
commit fcf3d633d8 ("nbd: check sock index in nbd_read_stat()") just
add error message when socket index doesn't match. Since the request
and reply must be transmitted over the same socket, it's ok to error
out in such situation.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20211101092538.1155842-1-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-02 14:42:41 -06:00
Ye Bin
e2daec488c nbd: Fix hungtask when nbd_config_put
I got follow issue:
[  247.381177] INFO: task kworker/u10:0:47 blocked for more than 120 seconds.
[  247.382644]       Not tainted 4.19.90-dirty #140
[  247.383502] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  247.385027] Call Trace:
[  247.388384]  schedule+0xb8/0x3c0
[  247.388966]  schedule_timeout+0x2b4/0x380
[  247.392815]  wait_for_completion+0x367/0x510
[  247.397713]  flush_workqueue+0x32b/0x1340
[  247.402700]  drain_workqueue+0xda/0x3c0
[  247.403442]  destroy_workqueue+0x7b/0x690
[  247.405014]  nbd_config_put.cold+0x2f9/0x5b6
[  247.405823]  recv_work+0x1fd/0x2b0
[  247.406485]  process_one_work+0x70b/0x1610
[  247.407262]  worker_thread+0x5a9/0x1060
[  247.408699]  kthread+0x35e/0x430
[  247.410918]  ret_from_fork+0x1f/0x30

We can reproduce issue as follows:
1. Inject memory fault in nbd_start_device
-1244,10 +1248,18 @@ static int nbd_start_device(struct nbd_device *nbd)
        nbd_dev_dbg_init(nbd);
        for (i = 0; i < num_connections; i++) {
                struct recv_thread_args *args;
-
-               args = kzalloc(sizeof(*args), GFP_KERNEL);
+
+               if (i == 1) {
+                       args = NULL;
+                       printk("%s: inject malloc error\n", __func__);
+               }
+               else
+                       args = kzalloc(sizeof(*args), GFP_KERNEL);
2. Inject delay in recv_work
-757,6 +760,8 @@ static void recv_work(struct work_struct *work)

                blk_mq_complete_request(blk_mq_rq_from_pdu(cmd));
        }
+       printk("%s: comm=%s pid=%d\n", __func__, current->comm, current->pid);
+       mdelay(5 * 1000);
        nbd_config_put(nbd);
        atomic_dec(&config->recv_threads);
        wake_up(&config->recv_wq);
3. Create nbd server
nbd-server 8000 /tmp/disk
4. Create nbd client
nbd-client localhost 8000 /dev/nbd1
Then will trigger above issue.

Reason is when add delay in recv_work, lead to release the last reference
of 'nbd->config_refs'. nbd_config_put will call flush_workqueue to make
all work finish. Obviously, it will lead to deadloop.
To solve this issue, according to Josef's suggestion move 'recv_work'
init from start device to nbd_dev_add, then destroy 'recv_work'when
nbd device teardown.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20211102015237.2309763-5-yebin10@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-02 10:50:27 -06:00
Ye Bin
69beb62ff0 nbd: Fix incorrect error handle when first_minor is illegal in nbd_dev_add
If first_minor is illegal will goto out_free_idr label, this will miss
cleanup disk.

Fixes: b1a811633f ("block: nbd: add sanity check for first_minor")
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20211102015237.2309763-4-yebin10@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-02 10:50:27 -06:00
Yu Kuai
940c264984 nbd: fix possible overflow for 'first_minor' in nbd_dev_add()
If 'part_shift' is not zero, then 'index << part_shift' might
overflow to a value that is not greater than '0xfffff', then sysfs
might complains about duplicate creation.

Fixes: b0d9111a2d ("nbd: use an idr to keep track of nbd devices")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20211102015237.2309763-3-yebin10@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-02 10:50:27 -06:00
Yu Kuai
e4c4871a73 nbd: fix max value for 'first_minor'
commit b1a811633f ("block: nbd: add sanity check for first_minor")
checks that 'first_minor' should not be greater than 0xff, which is
wrong. Whitout the commit, the details that when user pass 0x100000,
it ends up create sysfs dir "/sys/block/43:0" are as follows:

nbd_dev_add
 disk->first_minor = index << part_shift
  -> default part_shift is 5, first_minor is 0x2000000
  device_add_disk
   ddev->devt = MKDEV(disk->major, disk->first_minor)
    -> (0x2b << 20) | (0x2000000) = 0x2b00000
   device_add
    device_create_sys_dev_entry
	 format_dev_t
	  sprintf(buffer, "%u:%u", MAJOR(dev), MINOR(dev));
	   -> got 43:0
	  sysfs_create_link -> /sys/block/43:0

By the way, with the wrong fix, when part_shift is the default value,
only 8 ndb devices can be created since 8 << 5 is greater than 0xff.

Since the max bits for 'first_minor' should be the same as what
MKDEV() does, which is 20. Change the upper bound of 'first_minor'
from 0xff to 0xfffff.

Fixes: b1a811633f ("block: nbd: add sanity check for first_minor")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20211102015237.2309763-2-yebin10@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-02 10:50:27 -06:00
Linus Torvalds
643a7234e0 for-5.16/drivers-2021-10-29
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Merge tag 'for-5.16/drivers-2021-10-29' of git://git.kernel.dk/linux-block

Pull block driver updates from Jens Axboe:

 - paride driver cleanups (Christoph)

 - Remove cryptoloop support (Christoph)

 - null_blk poll support (me)

 - Now that add_disk() supports proper error handling, add it to various
   drivers (Luis)

 - Make ataflop actually work again (Michael)

 - s390 dasd fixes (Stefan, Heiko)

 - nbd fixes (Yu, Ye)

 - Remove redundant wq flush in mtip32xx (Christophe)

 - NVMe updates
      - fix a multipath partition scanning deadlock (Hannes Reinecke)
      - generate uevent once a multipath namespace is operational again
        (Hannes Reinecke)
      - support unique discovery controller NQNs (Hannes Reinecke)
      - fix use-after-free when a port is removed (Israel Rukshin)
      - clear shadow doorbell memory on resets (Keith Busch)
      - use struct_size (Len Baker)
      - add error handling support for add_disk (Luis Chamberlain)
      - limit the maximal queue size for RDMA controllers (Max Gurtovoy)
      - use a few more symbolic names (Max Gurtovoy)
      - fix error code in nvme_rdma_setup_ctrl (Max Gurtovoy)
      - add support for ->map_queues on FC (Saurav Kashyap)
      - support the current discovery subsystem entry (Hannes Reinecke)
      - use flex_array_size and struct_size (Len Baker)

 - bcache fixes (Christoph, Coly, Chao, Lin, Qing)

 - MD updates (Christoph, Guoqing, Xiao)

 - Misc fixes (Dan, Ding, Jiapeng, Shin'ichiro, Ye)

* tag 'for-5.16/drivers-2021-10-29' of git://git.kernel.dk/linux-block: (117 commits)
  null_blk: Fix handling of submit_queues and poll_queues attributes
  block: ataflop: Fix warning comparing pointer to 0
  bcache: replace snprintf in show functions with sysfs_emit
  bcache: move uapi header bcache.h to bcache code directory
  nvmet: use flex_array_size and struct_size
  nvmet: register discovery subsystem as 'current'
  nvmet: switch check for subsystem type
  nvme: add new discovery log page entry definitions
  block: ataflop: more blk-mq refactoring fixes
  block: remove support for cryptoloop and the xor transfer
  mtd: add add_disk() error handling
  rnbd: add error handling support for add_disk()
  um/drivers/ubd_kern: add error handling support for add_disk()
  m68k/emu/nfblock: add error handling support for add_disk()
  xen-blkfront: add error handling support for add_disk()
  bcache: add error handling support for add_disk()
  dm: add add_disk() error handling
  block: aoe: fixup coccinelle warnings
  nvmet: use struct_size over open coded arithmetic
  nvme: drop scan_lock and always kick requeue list when removing namespaces
  ...
2021-11-01 09:27:38 -07:00
Xie Yongji
c4318d6cd0 nbd: Use blk_validate_block_size() to validate block size
Use the block layer helper to validate block size instead
of open coding it.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Link: https://lore.kernel.org/r/20211026144015.188-3-xieyongji@bytedance.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-27 14:15:53 -06:00
Xie Yongji
435c2acb30 nbd: Use invalidate_disk() helper on disconnect
When a nbd device encounters a writeback error, that error will
get propagated to the bd_inode's wb_err field. Then if this nbd
device's backend is disconnected and another is attached, we will
get back the previous writeback error on fsync, which is unexpected.

To fix it, let's use invalidate_disk() helper to invalidate the
disk on disconnect instead of just setting disk's capacity to zero.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210922123711.187-5-xieyongji@bytedance.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-21 10:12:41 -06:00
Ye Bin
0c98057be9 nbd: Fix use-after-free in pid_show
I got issue as follows:
[  263.886511] BUG: KASAN: use-after-free in pid_show+0x11f/0x13f
[  263.888359] Read of size 4 at addr ffff8880bf0648c0 by task cat/746
[  263.890479] CPU: 0 PID: 746 Comm: cat Not tainted 4.19.90-dirty #140
[  263.893162] Call Trace:
[  263.893509]  dump_stack+0x108/0x15f
[  263.893999]  print_address_description+0xa5/0x372
[  263.894641]  kasan_report.cold+0x236/0x2a8
[  263.895696]  __asan_report_load4_noabort+0x25/0x30
[  263.896365]  pid_show+0x11f/0x13f
[  263.897422]  dev_attr_show+0x48/0x90
[  263.898361]  sysfs_kf_seq_show+0x24d/0x4b0
[  263.899479]  kernfs_seq_show+0x14e/0x1b0
[  263.900029]  seq_read+0x43f/0x1150
[  263.900499]  kernfs_fop_read+0xc7/0x5a0
[  263.903764]  vfs_read+0x113/0x350
[  263.904231]  ksys_read+0x103/0x270
[  263.905230]  __x64_sys_read+0x77/0xc0
[  263.906284]  do_syscall_64+0x106/0x360
[  263.906797]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reproduce this issue as follows:
1. nbd-server 8000 /tmp/disk
2. nbd-client localhost 8000 /dev/nbd1
3. cat /sys/block/nbd1/pid
Then trigger use-after-free in pid_show.

Reason is after do step '2', nbd-client progress is already exit. So
it's task_struct already freed.
To solve this issue, revert part of 6521d39a64b3's modify and remove
useless 'recv_task' member of nbd_device.

Fixes: 6521d39a64 ("nbd: Remove variable 'pid'")
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20211020073959.2679255-1-yebin10@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-20 08:09:56 -06:00
Yu Kuai
8663b210f8 nbd: fix uaf in nbd_handle_reply()
There is a problem that nbd_handle_reply() might access freed request:

1) At first, a normal io is submitted and completed with scheduler:

internel_tag = blk_mq_get_tag -> get tag from sched_tags
 blk_mq_rq_ctx_init
  sched_tags->rq[internel_tag] = sched_tag->static_rq[internel_tag]
...
blk_mq_get_driver_tag
 __blk_mq_get_driver_tag -> get tag from tags
 tags->rq[tag] = sched_tag->static_rq[internel_tag]

So, both tags->rq[tag] and sched_tags->rq[internel_tag] are pointing
to the request: sched_tags->static_rq[internal_tag]. Even if the
io is finished.

2) nbd server send a reply with random tag directly:

recv_work
 nbd_handle_reply
  blk_mq_tag_to_rq(tags, tag)
   rq = tags->rq[tag]

3) if the sched_tags->static_rq is freed:

blk_mq_sched_free_requests
 blk_mq_free_rqs(q->tag_set, hctx->sched_tags, i)
  -> step 2) access rq before clearing rq mapping
  blk_mq_clear_rq_mapping(set, tags, hctx_idx);
  __free_pages() -> rq is freed here

4) Then, nbd continue to use the freed request in nbd_handle_reply

Fix the problem by get 'q_usage_counter' before blk_mq_tag_to_rq(),
thus request is ensured not to be freed because 'q_usage_counter' is
not zero.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210916141810.2325276-1-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:50:37 -06:00
Yu Kuai
3fe1db626a nbd: partition nbd_read_stat() into nbd_read_reply() and nbd_handle_reply()
Prepare to fix uaf in nbd_read_stat(), no functional changes.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20210916093350.1410403-7-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:50:37 -06:00
Yu Kuai
f52c0e0823 nbd: clean up return value checking of sock_xmit()
Check if sock_xmit() return 0 is useless because it'll never return
0, comment it and remove such checkings.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20210916093350.1410403-6-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:50:37 -06:00
Yu Kuai
0de2b7a4dd nbd: don't start request if nbd_queue_rq() failed
commit 6a468d5990 ("nbd: don't start req until after the dead
connection logic") move blk_mq_start_request() from nbd_queue_rq()
to nbd_handle_cmd() to skip starting request if the connection is
dead. However, request is still started in other error paths.

Currently, blk_mq_end_request() will be called immediately if
nbd_queue_rq() failed, thus start request in such situation is
useless. So remove blk_mq_start_request() from error paths in
nbd_handle_cmd().

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20210916093350.1410403-5-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:50:37 -06:00
Yu Kuai
fcf3d633d8 nbd: check sock index in nbd_read_stat()
The sock that clent send request in nbd_send_cmd() and receive reply
in nbd_read_stat() should be the same.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20210916093350.1410403-4-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:50:37 -06:00
Yu Kuai
07175cb1ba nbd: make sure request completion won't concurrent
commit cddce01160 ("nbd: Aovid double completion of a request")
try to fix that nbd_clear_que() and recv_work() can complete a
request concurrently. However, the problem still exists:

t1                    t2                     t3

nbd_disconnect_and_put
 flush_workqueue
                      recv_work
                       blk_mq_complete_request
                        blk_mq_complete_request_remote -> this is true
                         WRITE_ONCE(rq->state, MQ_RQ_COMPLETE)
                          blk_mq_raise_softirq
                                             blk_done_softirq
                                              blk_complete_reqs
                                               nbd_complete_rq
                                                blk_mq_end_request
                                                 blk_mq_free_request
                                                  WRITE_ONCE(rq->state, MQ_RQ_IDLE)
  nbd_clear_que
   blk_mq_tagset_busy_iter
    nbd_clear_req
                                                   __blk_mq_free_request
                                                    blk_mq_put_tag
     blk_mq_complete_request -> complete again

There are three places where request can be completed in nbd:
recv_work(), nbd_clear_que() and nbd_xmit_timeout(). Since they
all hold cmd->lock before completing the request, it's easy to
avoid the problem by setting and checking a cmd flag.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20210916093350.1410403-3-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:50:37 -06:00
Yu Kuai
4e6eef5dc2 nbd: don't handle response without a corresponding request message
While handling a response message from server, nbd_read_stat() will
try to get request by tag, and then complete the request. However,
this is problematic if nbd haven't sent a corresponding request
message:

t1                      t2
                        submit_bio
                         nbd_queue_rq
                          blk_mq_start_request
recv_work
 nbd_read_stat
  blk_mq_tag_to_rq
 blk_mq_complete_request
                          nbd_send_cmd

Thus add a new cmd flag 'NBD_CMD_INFLIGHT', it will be set in
nbd_send_cmd() and checked in nbd_read_stat().

Noted that this patch can't fix that blk_mq_tag_to_rq() might
return a freed request, and this will be fixed in following
patches.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20210916093350.1410403-2-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:50:37 -06:00
Luis Chamberlain
e1654f413f nbd: add error handling support for add_disk()
We never checked for errors on add_disk() as this function
returned void. Now that this is fixed, use the shiny new
error handling.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:41:36 -06:00
Nick Desaulniers
41e76c6a3c nbd: use shifts rather than multiplies
commit fad7cd3310 ("nbd: add the check to prevent overflow in
__nbd_ioctl()") raised an issue from the fallback helpers added in
commit f0907827a8 ("compiler.h: enable builtin overflow checkers and
add fallback code")

ERROR: modpost: "__divdi3" [drivers/block/nbd.ko] undefined!

As Stephen Rothwell notes:
  The added check_mul_overflow() call is being passed 64 bit values.
  COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW is not set for this build (see
  include/linux/overflow.h).

Specifically, the helpers for checking whether the results of a
multiplication overflowed (__unsigned_mul_overflow,
__signed_add_overflow) use the division operator when
!COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW.  This is problematic for 64b
operands on 32b hosts.

This was fixed upstream by
commit 76ae847497 ("Documentation: raise minimum supported version of
GCC to 5.1")
which is not suitable to be backported to stable.

Further, __builtin_mul_overflow() would emit a libcall to a
compiler-rt-only symbol when compiling with clang < 14 for 32b targets.

ld.lld: error: undefined symbol: __mulodi4

In order to keep stable buildable with GCC 4.9 and clang < 14, modify
struct nbd_config to instead track the number of bits of the block size;
reconstructing the block size using runtime checked shifts that are not
problematic for those compilers and in a ways that can be backported to
stable.

In nbd_set_size, we do validate that the value of blksize must be a
power of two (POT) and is in the range of [512, PAGE_SIZE] (both
inclusive).

This does modify the debugfs interface.

Cc: stable@vger.kernel.org
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: https://github.com/ClangBuiltLinux/linux/issues/1438
Link: https://lore.kernel.org/all/20210909182525.372ee687@canb.auug.org.au/
Link: https://lore.kernel.org/stable/CAHk-=whiQBofgis_rkniz8GBP9wZtSZdcDEffgSLO62BUGV3gg@mail.gmail.com/
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Suggested-by: Kees Cook <keescook@chromium.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20210920232533.4092046-1-ndesaulniers@google.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-29 20:31:41 -06:00
Linus Torvalds
9a1d6c9e3f for-5.15/drivers-2021-08-30
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Merge tag 'for-5.15/drivers-2021-08-30' of git://git.kernel.dk/linux-block

Pull block driver updates from Jens Axboe:
 "Sitting on top of the core block changes, here are the driver changes
  for the 5.15 merge window:

   - NVMe updates via Christoph:
       - suspend improvements for devices with an HMB (Keith Busch)
       - handle double completions more gacefull (Sagi Grimberg)
       - cleanup the selects for the nvme core code a bit (Sagi Grimberg)
       - don't update queue count when failing to set io queues (Ruozhu Li)
       - various nvmet connect fixes (Amit Engel)
       - cleanup lightnvm leftovers (Keith Busch, me)
       - small cleanups (Colin Ian King, Hou Pu)
       - add tracing for the Set Features command (Hou Pu)
       - CMB sysfs cleanups (Keith Busch)
       - add a mutex_destroy call (Keith Busch)

   - remove lightnvm subsystem. It's served its purpose and ultimately
     led to zoned nvme support, we no longer need it (Christoph)

   - revert floppy O_NDELAY fix (Denis)

   - nbd fixes (Hou, Pavel, Baokun)

   - nbd locking fixes (Tetsuo)

   - nbd device removal fixes (Christoph)

   - raid10 rcu warning fix (Xiao)

   - raid1 write behind fix (Guoqing)

   - rnbd fixes (Gioh, Md Haris)

   - misc fixes (Colin)"

* tag 'for-5.15/drivers-2021-08-30' of git://git.kernel.dk/linux-block: (42 commits)
  Revert "floppy: reintroduce O_NDELAY fix"
  raid1: ensure write behind bio has less than BIO_MAX_VECS sectors
  md/raid10: Remove unnecessary rcu_dereference in raid10_handle_discard
  nbd: remove nbd->destroy_complete
  nbd: only return usable devices from nbd_find_unused
  nbd: set nbd->index before releasing nbd_index_mutex
  nbd: prevent IDR lookups from finding partially initialized devices
  nbd: reset NBD to NULL when restarting in nbd_genl_connect
  nbd: add missing locking to the nbd_dev_add error path
  nvme: remove the unused NVME_NS_* enum
  nvme: remove nvm_ndev from ns
  nvme: Have NVME_FABRICS select NVME_CORE instead of transport drivers
  block: nbd: add sanity check for first_minor
  nvmet: check that host sqsize does not exceed ctrl MQES
  nvmet: avoid duplicate qid in connect cmd
  nvmet: pass back cntlid on successful completion
  nvme-rdma: don't update queue count when failing to set io queues
  nvme-tcp: don't update queue count when failing to set io queues
  nvme-tcp: pair send_mutex init with destroy
  nvme: allow user toggling hmb usage
  ...
2021-08-30 19:01:46 -07:00
Christoph Hellwig
7ee656c3ac nbd: remove nbd->destroy_complete
The nbd->destroy_complete pointer is not really needed.  For creating
a device without a specific index we now simplify skip devices marked
NBD_DESTROY_ON_DISCONNECT as there is not much point to reuse them.
For device creation with a specific index there is no real need to
treat the case of a requested but not finished disconnect different
than any other device that is being shutdown, i.e. we can just return
an error, as a slightly different race window would anyway.

Fixes: 6e4df4c648 ("nbd: reduce the nbd_index_mutex scope")
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot+2c98885bcd769f56b6d6@syzkaller.appspotmail.com
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210825163108.50713-7-hch@lst.de
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-25 14:20:32 -06:00
Christoph Hellwig
438cd318c8 nbd: only return usable devices from nbd_find_unused
Device marked as NBD_DESTROY_ON_DISCONNECT can and should be skipped
given that they won't survive the disconnect.  So skip them and try
to grab a reference directly and just continue if the the devices
is being torn down or created and thus has a zero refcount.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210825163108.50713-6-hch@lst.de
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-25 14:20:29 -06:00
Tetsuo Handa
b190300dec nbd: set nbd->index before releasing nbd_index_mutex
Set nbd->index before releasing nbd_index_mutex, as populate_nbd_status()
might access nbd->index as soon as nbd_index_mutex is released.

Fixes: 6e4df4c648 ("nbd: reduce the nbd_index_mutex scope")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
[hch: split from a larger patch]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210825163108.50713-5-hch@lst.de
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-25 14:20:25 -06:00
Tetsuo Handa
75b7f62aa6 nbd: prevent IDR lookups from finding partially initialized devices
Previously nbd_index_mutex was held during whole add/remove/lookup
operations in order to guarantee that partially initialized devices are
not reachable via idr_find() or idr_for_each(). But now that partially
initialized devices become reachable as soon as idr_alloc() succeeds,
we need to skip partially initialized devices. Since it seems that
all functions use refcount_inc_not_zero(&nbd->refs) in order to skip
destroying devices, update nbd->refs from zero to non-zero as the last
step of device initialization in order to also skip partially initialized
devices.

Fixes: 6e4df4c648 ("nbd: reduce the nbd_index_mutex scope")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
[hch: split from a larger patch, added comments]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210825163108.50713-4-hch@lst.de
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-25 14:20:22 -06:00
Christoph Hellwig
409e0ff10e nbd: reset NBD to NULL when restarting in nbd_genl_connect
When nbd_genl_connect restarts to wait for a disconnecting device, nbd
needs to be reset to NULL.  Do that by facoring out a helper to find
an unused device.

Fixes: 6177b56c96 ("nbd: refactor device search and allocation in nbd_genl_connect")
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Reported-by: Hillf Danton <hdanton@sina.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210825163108.50713-3-hch@lst.de
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-25 14:20:20 -06:00
Tetsuo Handa
93f63bc41f nbd: add missing locking to the nbd_dev_add error path
idr_remove needs external synchronization.

Fixes: 6e4df4c648 ("nbd: reduce the nbd_index_mutex scope")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
[hch: split from a larger patch]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210825163108.50713-2-hch@lst.de
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-25 14:20:08 -06:00
Pavel Skripkin
b1a811633f block: nbd: add sanity check for first_minor
Syzbot hit WARNING in internal_create_group(). The problem was in
too big disk->first_minor.

disk->first_minor is initialized by value, which comes from userspace
and there wasn't any sanity checks about value correctness. It can cause
duplicate creation of sysfs files/links, because disk->first_minor will
be passed to MKDEV() which causes truncation to byte. Since maximum
minor value is 0xff, let's check if first_minor is correct minor number.

NOTE: the root case of the reported warning was in wrong error handling
in register_disk(), but we can avoid passing knowingly wrong values to
sysfs API, because sysfs error messages can confuse users. For example:
user passed 1048576 as index, but sysfs complains about duplicate
creation of /dev/block/43:0. It's not obvious how 1048576 becomes 0.
Log and reproducer for above example can be found on syzkaller bug
report page.

Link: https://syzkaller.appspot.com/bug?id=03c2ae9146416edf811958d5fd7acfab75b143d1
Fixes: b0d9111a2d ("nbd: use an idr to keep track of nbd devices")
Reported-by: syzbot+9937dc42271cd87d4b98@syzkaller.appspotmail.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-16 10:56:33 -06:00
Christoph Hellwig
6e4df4c648 nbd: reduce the nbd_index_mutex scope
nbd_index_mutex is currently held over add_disk and inside ->open, which
leads to lock order reversals.  Refactor the device creation code path
so that nbd_dev_add is called without nbd_index_mutex lock held and
only takes it for the IDR insertation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210811124428.2368491-7-hch@lst.de
[axboe: fix whitespace]
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-13 14:17:41 -06:00
Christoph Hellwig
6177b56c96 nbd: refactor device search and allocation in nbd_genl_connect
Use idr_for_each_entry instead of the awkward callback to find an
existing device for the index == -1 case, and de-duplicate the device
allocation if no existing device was found.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210811124428.2368491-6-hch@lst.de
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-13 14:17:39 -06:00
Christoph Hellwig
7bdc00cf7e nbd: return the allocated nbd_device from nbd_dev_add
Return the device we just allocated instead of doing an extra search for
it in the caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210811124428.2368491-5-hch@lst.de
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-13 14:17:37 -06:00
Christoph Hellwig
327b501b1d nbd: remove nbd_del_disk
Fold nbd_del_disk and remove the pointless NULL check on ->disk given
that it is always set for a successfully allocated nbd_device structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210811124428.2368491-4-hch@lst.de
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-13 14:17:36 -06:00
Christoph Hellwig
3f74e0645c nbd: refactor device removal
Share common code for the synchronous and workqueue based device removal,
and remove the pointless use of refcount_dec_and_mutex_lock.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210811124428.2368491-3-hch@lst.de
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-13 14:17:32 -06:00
Hou Tao
68c9417b19 nbd: do del_gendisk() asynchronously for NBD_DESTROY_ON_DISCONNECT
Now open_mutex is used to synchronize partition operations (e.g,
blk_drop_partitions() and blkdev_reread_part()), however it makes
nbd driver broken, because nbd may call del_gendisk() in nbd_release()
or nbd_genl_disconnect() if NBD_CFLAG_DESTROY_ON_DISCONNECT is enabled,
and deadlock occurs, as shown below:

// AB-BA dead-lock
nbd_genl_disconnect            blkdev_open
  nbd_disconnect_and_put
                                 lock bd_mutex
  // last ref
  nbd_put
    lock nbd_index_mutex
      del_gendisk
                                   nbd_open
                                     try lock nbd_index_mutex
        try lock bd_mutex

 or

// AA dead-lock
nbd_release
  lock bd_mutex
    nbd_put
      try lock bd_mutex

Instead of fixing block layer (e.g, introduce another lock), fixing
the nbd driver to call del_gendisk() in a kworker when
NBD_DESTROY_ON_DISCONNECT is enabled. When NBD_DESTROY_ON_DISCONNECT
is disabled, nbd device will always be destroy through module removal,
and there is no risky of deadlock.

To ensure the reuse of nbd index succeeds, moving the calling of
idr_remove() after del_gendisk(), so if the reused index is not found
in nbd_index_idr, the old disk must have been deleted. And reusing
the existing destroy_complete mechanism to ensure nbd_genl_connect()
will wait for the completion of del_gendisk().

Also adding a new workqueue for nbd removal, so nbd_cleanup()
can ensure all removals complete before exits.

Reported-by: syzbot+0fe7752e52337864d29b@syzkaller.appspotmail.com
Fixes: c76f48eb5c ("block: take bd_mutex around delete_partitions in del_gendisk")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210811124428.2368491-2-hch@lst.de
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-13 14:17:16 -06:00
Baokun Li
fad7cd3310 nbd: add the check to prevent overflow in __nbd_ioctl()
If user specify a large enough value of NBD blocks option, it may trigger
signed integer overflow which may lead to nbd->config->bytesize becomes a
large or small value, zero in particular.

UBSAN: Undefined behaviour in drivers/block/nbd.c:325:31
signed integer overflow:
1024 * 4611686155866341414 cannot be represented in type 'long long int'
[...]
Call trace:
[...]
 handle_overflow+0x188/0x1dc lib/ubsan.c:192
 __ubsan_handle_mul_overflow+0x34/0x44 lib/ubsan.c:213
 nbd_size_set drivers/block/nbd.c:325 [inline]
 __nbd_ioctl drivers/block/nbd.c:1342 [inline]
 nbd_ioctl+0x998/0xa10 drivers/block/nbd.c:1395
 __blkdev_driver_ioctl block/ioctl.c:311 [inline]
[...]

Although it is not a big deal, still silence the UBSAN by limit
the input value.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20210804021212.990223-1-libaokun1@huawei.com
[axboe: dropped unlikely()]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-13 10:09:26 -06:00
Xie Yongji
cddce01160 nbd: Aovid double completion of a request
There is a race between iterating over requests in
nbd_clear_que() and completing requests in recv_work(),
which can lead to double completion of a request.

To fix it, flush the recv worker before iterating over
the requests and don't abort the completed request
while iterating.

Fixes: 96d97e1782 ("nbd: clear_sock on netlink disconnect")
Reported-by: Jiang Yadong <jiangyadong@bytedance.com>
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20210813151330.96-1-xieyongji@bytedance.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-13 09:46:48 -06:00
Wang Qing
16ad3db3b2 nbd: fix order of cleaning up the queue and freeing the tagset
We must release the queue before freeing the tagset.

Fixes: 4af5f2e030 ("nbd: use blk_mq_alloc_disk and blk_cleanup_disk")
Reported-and-tested-by: syzbot+9ca43ff47167c0ee3466@syzkaller.appspotmail.com
Signed-off-by: Wang Qing <wangqing@vivo.com>
Signed-off-by: Guoqing Jiang <jiangguoqing@kylinos.cn>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210706040016.1360412-1-guoqing.jiang@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-07-15 09:30:15 -06:00
Prasanna Kumar Kalever
6497ef8df5 nbd: provide a way for userspace processes to identify device backends
Problem:
On reconfigure of device, there is no way to defend if the backend
storage is matching with the initial backend storage.

Say, if an initial connect request for backend "pool1/image1" got
mapped to /dev/nbd0 and the userspace process is terminated. A next
reconfigure request within NBD_ATTR_DEAD_CONN_TIMEOUT is allowed to
use /dev/nbd0 for a different backend "pool1/image2"

For example, an operation like below could be dangerous:

$ sudo rbd-nbd map --try-netlink rbd-pool/ext4-image
/dev/nbd0
$ sudo blkid /dev/nbd0
/dev/nbd0: UUID="bfc444b4-64b1-418f-8b36-6e0d170cfc04" TYPE="ext4"
$ sudo pkill -9 rbd-nbd
$ sudo rbd-nbd attach --try-netlink --device /dev/nbd0 rbd-pool/xfs-image
/dev/nbd0
$ sudo blkid /dev/nbd0
/dev/nbd0: UUID="d29bf343-6570-4069-a9ea-2fa156ced908" TYPE="xfs"

Solution:
Provide a way for userspace processes to keep some metadata to identify
between the device and the backend, so that when a reconfigure request is
made, we can compare and avoid such dangerous operations.

With this solution, as part of the initial connect request, backend
path can be stored in the sysfs per device config, so that on a reconfigure
request it's easy to check if the backend path matches with the initial
connect backend path.

Please note, ioctl interface to nbd will not have these changes, as there
won't be any reconfigure.

Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210429102828.31248-1-prasanna.kalever@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-30 15:34:04 -06:00
Christoph Hellwig
4af5f2e030 nbd: use blk_mq_alloc_disk and blk_cleanup_disk
Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-20-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-11 11:53:03 -06:00
Sun Ke
bedf78c4cb nbd: share nbd_put and return by goto put_nbd
Replace the following two statements by the statement “goto put_nbd;”

	nbd_put(nbd);
	return 0;

Signed-off-by: Sun Ke <sunke32@huawei.com>
Suggested-by: Markus Elfring <Markus.Elfring@web.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20210512114331.1233964-3-sunke32@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-05-12 08:42:43 -06:00
Sun Ke
79ebe9110f nbd: Fix NULL pointer in flush_workqueue
Open /dev/nbdX first, the config_refs will be 1 and
the pointers in nbd_device are still null. Disconnect
/dev/nbdX, then reference a null recv_workq. The
protection by config_refs in nbd_genl_disconnect is useless.

[  656.366194] BUG: kernel NULL pointer dereference, address: 0000000000000020
[  656.368943] #PF: supervisor write access in kernel mode
[  656.369844] #PF: error_code(0x0002) - not-present page
[  656.370717] PGD 10cc87067 P4D 10cc87067 PUD 1074b4067 PMD 0
[  656.371693] Oops: 0002 [#1] SMP
[  656.372242] CPU: 5 PID: 7977 Comm: nbd-client Not tainted 5.11.0-rc5-00040-g76c057c84d28 #1
[  656.373661] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
[  656.375904] RIP: 0010:mutex_lock+0x29/0x60
[  656.376627] Code: 00 0f 1f 44 00 00 55 48 89 fd 48 83 05 6f d7 fe 08 01 e8 7a c3 ff ff 48 83 05 6a d7 fe 08 01 31 c0 65 48 8b 14 25 00 6d 01 00 <f0> 48 0f b1 55 d
[  656.378934] RSP: 0018:ffffc900005eb9b0 EFLAGS: 00010246
[  656.379350] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[  656.379915] RDX: ffff888104cf2600 RSI: ffffffffaae8f452 RDI: 0000000000000020
[  656.380473] RBP: 0000000000000020 R08: 0000000000000000 R09: ffff88813bd6b318
[  656.381039] R10: 00000000000000c7 R11: fefefefefefefeff R12: ffff888102710b40
[  656.381599] R13: ffffc900005eb9e0 R14: ffffffffb2930680 R15: ffff88810770ef00
[  656.382166] FS:  00007fdf117ebb40(0000) GS:ffff88813bd40000(0000) knlGS:0000000000000000
[  656.382806] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  656.383261] CR2: 0000000000000020 CR3: 0000000100c84000 CR4: 00000000000006e0
[  656.383819] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  656.384370] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  656.384927] Call Trace:
[  656.385111]  flush_workqueue+0x92/0x6c0
[  656.385395]  nbd_disconnect_and_put+0x81/0xd0
[  656.385716]  nbd_genl_disconnect+0x125/0x2a0
[  656.386034]  genl_family_rcv_msg_doit.isra.0+0x102/0x1b0
[  656.386422]  genl_rcv_msg+0xfc/0x2b0
[  656.386685]  ? nbd_ioctl+0x490/0x490
[  656.386954]  ? genl_family_rcv_msg_doit.isra.0+0x1b0/0x1b0
[  656.387354]  netlink_rcv_skb+0x62/0x180
[  656.387638]  genl_rcv+0x34/0x60
[  656.387874]  netlink_unicast+0x26d/0x590
[  656.388162]  netlink_sendmsg+0x398/0x6c0
[  656.388451]  ? netlink_rcv_skb+0x180/0x180
[  656.388750]  ____sys_sendmsg+0x1da/0x320
[  656.389038]  ? ____sys_recvmsg+0x130/0x220
[  656.389334]  ___sys_sendmsg+0x8e/0xf0
[  656.389605]  ? ___sys_recvmsg+0xa2/0xf0
[  656.389889]  ? handle_mm_fault+0x1671/0x21d0
[  656.390201]  __sys_sendmsg+0x6d/0xe0
[  656.390464]  __x64_sys_sendmsg+0x23/0x30
[  656.390751]  do_syscall_64+0x45/0x70
[  656.391017]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

To fix it, just add if (nbd->recv_workq) to nbd_disconnect_and_put().

Fixes: e9e006f5fc ("nbd: fix max number of supported devs")
Signed-off-by: Sun Ke <sunke32@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20210512114331.1233964-2-sunke32@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-05-12 08:42:43 -06:00
Josef Bacik
c9a2f90f4d nbd: handle device refs for DESTROY_ON_DISCONNECT properly
There exists a race where we can be attempting to create a new nbd
configuration while a previous configuration is going down, both
configured with DESTROY_ON_DISCONNECT.  Normally devices all have a
reference of 1, as they won't be cleaned up until the module is torn
down.  However with DESTROY_ON_DISCONNECT we'll make sure that there is
only 1 reference (generally) on the device for the config itself, and
then once the config is dropped, the device is torn down.

The race that exists looks like this

TASK1					TASK2
nbd_genl_connect()
  idr_find()
    refcount_inc_not_zero(nbd)
      * count is 2 here ^^
					nbd_config_put()
					  nbd_put(nbd) (count is 1)
    setup new config
      check DESTROY_ON_DISCONNECT
	put_dev = true
    if (put_dev) nbd_put(nbd)
	* free'd here ^^

In nbd_genl_connect() we assume that the nbd ref count will be 2,
however clearly that won't be true if the nbd device had been setup as
DESTROY_ON_DISCONNECT with its prior configuration.  Fix this by getting
rid of the runtime flag to check if we need to mess with the nbd device
refcount, and use the device NBD_DESTROY_ON_DISCONNECT flag to check if
we need to adjust the ref counts.  This was reported by syzkaller with
the following kasan dump

BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:71 [inline]
BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:27 [inline]
BUG: KASAN: use-after-free in refcount_dec_not_one+0x71/0x1e0 lib/refcount.c:76
Read of size 4 at addr ffff888143bf71a0 by task systemd-udevd/8451

CPU: 0 PID: 8451 Comm: systemd-udevd Not tainted 5.11.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:230
 __kasan_report mm/kasan/report.c:396 [inline]
 kasan_report.cold+0x79/0xd5 mm/kasan/report.c:413
 check_memory_region_inline mm/kasan/generic.c:179 [inline]
 check_memory_region+0x13d/0x180 mm/kasan/generic.c:185
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 atomic_read include/asm-generic/atomic-instrumented.h:27 [inline]
 refcount_dec_not_one+0x71/0x1e0 lib/refcount.c:76
 refcount_dec_and_mutex_lock+0x19/0x140 lib/refcount.c:115
 nbd_put drivers/block/nbd.c:248 [inline]
 nbd_release+0x116/0x190 drivers/block/nbd.c:1508
 __blkdev_put+0x548/0x800 fs/block_dev.c:1579
 blkdev_put+0x92/0x570 fs/block_dev.c:1632
 blkdev_close+0x8c/0xb0 fs/block_dev.c:1640
 __fput+0x283/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x190 kernel/task_work.c:140
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fc1e92b5270
Code: 73 01 c3 48 8b 0d 38 7d 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 59 c1 20 00 00 75 10 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 ee fb ff ff 48 89 04 24
RSP: 002b:00007ffe8beb2d18 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007fc1e92b5270
RDX: 000000000aba9500 RSI: 0000000000000000 RDI: 0000000000000007
RBP: 00007fc1ea16f710 R08: 000000000000004a R09: 0000000000000008
R10: 0000562f8cb0b2a8 R11: 0000000000000246 R12: 0000000000000000
R13: 0000562f8cb0afd0 R14: 0000000000000003 R15: 000000000000000e

Allocated by task 1:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:401 [inline]
 ____kasan_kmalloc.constprop.0+0x82/0xa0 mm/kasan/common.c:429
 kmalloc include/linux/slab.h:552 [inline]
 kzalloc include/linux/slab.h:682 [inline]
 nbd_dev_add+0x44/0x8e0 drivers/block/nbd.c:1673
 nbd_init+0x250/0x271 drivers/block/nbd.c:2394
 do_one_initcall+0x103/0x650 init/main.c:1223
 do_initcall_level init/main.c:1296 [inline]
 do_initcalls init/main.c:1312 [inline]
 do_basic_setup init/main.c:1332 [inline]
 kernel_init_freeable+0x605/0x689 init/main.c:1533
 kernel_init+0xd/0x1b8 init/main.c:1421
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Freed by task 8451:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:356
 ____kasan_slab_free+0xe1/0x110 mm/kasan/common.c:362
 kasan_slab_free include/linux/kasan.h:192 [inline]
 slab_free_hook mm/slub.c:1547 [inline]
 slab_free_freelist_hook+0x5d/0x150 mm/slub.c:1580
 slab_free mm/slub.c:3143 [inline]
 kfree+0xdb/0x3b0 mm/slub.c:4139
 nbd_dev_remove drivers/block/nbd.c:243 [inline]
 nbd_put.part.0+0x180/0x1d0 drivers/block/nbd.c:251
 nbd_put drivers/block/nbd.c:295 [inline]
 nbd_config_put+0x6dd/0x8c0 drivers/block/nbd.c:1242
 nbd_release+0x103/0x190 drivers/block/nbd.c:1507
 __blkdev_put+0x548/0x800 fs/block_dev.c:1579
 blkdev_put+0x92/0x570 fs/block_dev.c:1632
 blkdev_close+0x8c/0xb0 fs/block_dev.c:1640
 __fput+0x283/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x190 kernel/task_work.c:140
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff888143bf7000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 416 bytes inside of
 1024-byte region [ffff888143bf7000, ffff888143bf7400)
The buggy address belongs to the page:
page:000000005238f4ce refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x143bf0
head:000000005238f4ce order:3 compound_mapcount:0 compound_pincount:0
flags: 0x57ff00000010200(slab|head)
raw: 057ff00000010200 ffffea00004b1400 0000000300000003 ffff888010c41140
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888143bf7080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888143bf7100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888143bf7180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff888143bf7200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Reported-and-tested-by: syzbot+429d3f82d757c211bff3@syzkaller.appspotmail.com
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-22 13:17:23 -07:00
Linus Torvalds
9820b4dca0 for-5.12/drivers-2021-02-17
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Merge tag 'for-5.12/drivers-2021-02-17' of git://git.kernel.dk/linux-block

Pull block driver updates from Jens Axboe:

 - Remove the skd driver. It's been EOL for a long time (Damien)

 - NVMe pull requests
      - fix multipath handling of ->queue_rq errors (Chao Leng)
      - nvmet cleanups (Chaitanya Kulkarni)
      - add a quirk for buggy Amazon controller (Filippo Sironi)
      - avoid devm allocations in nvme-hwmon that don't interact well
        with fabrics (Hannes Reinecke)
      - sysfs cleanups (Jiapeng Chong)
      - fix nr_zones for multipath (Keith Busch)
      - nvme-tcp crash fix for no-data commands (Sagi Grimberg)
      - nvmet-tcp fixes (Sagi Grimberg)
      - add a missing __rcu annotation (Christoph)
      - failed reconnect fixes (Chao Leng)
      - various tracing improvements (Michal Krakowiak, Johannes
        Thumshirn)
      - switch the nvmet-fc assoc_list to use RCU protection (Leonid
        Ravich)
      - resync the status codes with the latest spec (Max Gurtovoy)
      - minor nvme-tcp improvements (Sagi Grimberg)
      - various cleanups (Rikard Falkeborn, Minwoo Im, Chaitanya
        Kulkarni, Israel Rukshin)

 - Floppy O_NDELAY fix (Denis)

 - MD pull request
      - raid5 chunk_sectors fix (Guoqing)

 - Use lore links (Kees)

 - Use DEFINE_SHOW_ATTRIBUTE for nbd (Liao)

 - loop lock scaling (Pavel)

 - mtip32xx PCI fixes (Bjorn)

 - bcache fixes (Kai, Dongdong)

 - Misc fixes (Tian, Yang, Guoqing, Joe, Andy)

* tag 'for-5.12/drivers-2021-02-17' of git://git.kernel.dk/linux-block: (64 commits)
  lightnvm: pblk: Replace guid_copy() with export_guid()/import_guid()
  lightnvm: fix unnecessary NULL check warnings
  nvme-tcp: fix crash triggered with a dataless request submission
  block: Replace lkml.org links with lore
  nbd: Convert to DEFINE_SHOW_ATTRIBUTE
  nvme: add 48-bit DMA address quirk for Amazon NVMe controllers
  nvme-hwmon: rework to avoid devm allocation
  nvmet: remove else at the end of the function
  nvmet: add nvmet_req_subsys() helper
  nvmet: use min of device_path and disk len
  nvmet: use invalid cmd opcode helper
  nvmet: use invalid cmd opcode helper
  nvmet: add helper to report invalid opcode
  nvmet: remove extra variable in id-ns handler
  nvmet: make nvmet_find_namespace() req based
  nvmet: return uniform error for invalid ns
  nvmet: set status to 0 in case for invalid nsid
  nvmet-fc: add a missing __rcu annotation to nvmet_fc_tgt_assoc.queues
  nvme-multipath: set nr_zones for zoned namespaces
  nvmet-tcp: fix potential race of tcp socket closing accept_work
  ...
2021-02-21 11:06:54 -08:00
Liao Pingfang
a2d52a6c1b nbd: Convert to DEFINE_SHOW_ATTRIBUTE
Use DEFINE_SHOW_ATTRIBUTE macro to simplify the code.

Signed-off-by: Liao Pingfang <winndows@163.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10 09:38:39 -07:00
Josef Bacik
b98e762e3d nbd: freeze the queue while we're adding connections
When setting up a device, we can krealloc the config->socks array to add
new sockets to the configuration.  However if we happen to get a IO
request in at this point even though we aren't setup we could hit a UAF,
as we deref config->socks without any locking, assuming that the
configuration was setup already and that ->socks is safe to access it as
we have a reference on the configuration.

But there's nothing really preventing IO from occurring at this point of
the device setup, we don't want to incur the overhead of a lock to
access ->socks when it will never change while the device is running.
To fix this UAF scenario simply freeze the queue if we are adding
sockets.  This will protect us from this particular case without adding
any additional overhead for the normal running case.

Cc: stable@vger.kernel.org
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-25 11:04:50 -07:00
Josh Triplett
1aba169e77 nbd: Respect max_part for all partition scans
The creation path of the NBD device respects max_part and only scans for
partitions if max_part is not 0. However, some other code paths ignore
max_part, and unconditionally scan for partitions. Add a check for
max_part on each partition scan.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-17 07:54:51 -07:00
Christoph Hellwig
977115c0f6 block: stop using bdget_disk for partition 0
We can just dereference the point in struct gendisk instead.  Also
remove the now unused export.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:40 -07:00
Christoph Hellwig
a782483cc1 block: remove the nr_sects field in struct hd_struct
Now that the hd_struct always has a block device attached to it, there is
no need for having two size field that just get out of sync.

Additionally the field in hd_struct did not use proper serialization,
possibly allowing for torn writes.  By only using the block_device field
this problem also gets fixed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Coly Li <colyli@suse.de>			[bcache]
Acked-by: Chao Yu <yuchao0@huawei.com>			[f2fs]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:40 -07:00
Christoph Hellwig
2ebcabf3db nbd: use set_capacity_and_notify
Use set_capacity_and_notify to update the disk and block device sizes and
send a RESIZE uevent to userspace.  Note that blktests relies on uevents
being sent also for updates that did not change the device size, so the
explicit kobject_uevent remains for that case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-16 08:34:14 -07:00
Christoph Hellwig
dcbddf541f nbd: validate the block size in nbd_set_size
Move the validation of the block from the callers into nbd_set_size.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-16 08:34:14 -07:00
Christoph Hellwig
2dc691cc4a nbd: refactor size updates
Merge nbd_size_set and nbd_size_update into a single function that also
updates the nbd_config fields.  This new function takes the device size
in bytes as the first argument, and the blocksize as the second argument,
simplifying the calculations required in most callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-16 08:34:14 -07:00