linux-stable.git/drivers/block, branch v5.4.201

nbd: fix io hung while disconnecting device

2022-06-14T16:12:01+00:00

[ Upstream commit 09dadb5985023e27d4740ebd17e6fea4640110e5 ]

In our tests, "qemu-nbd" triggers a io hung:

INFO: task qemu-nbd:11445 blocked for more than 368 seconds.
      Not tainted 5.18.0-rc3-next-20220422-00003-g2176915513ca #884
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:qemu-nbd        state:D stack:    0 pid:11445 ppid:     1 flags:0x00000000
Call Trace:
 
 __schedule+0x480/0x1050
 ? _raw_spin_lock_irqsave+0x3e/0xb0
 schedule+0x9c/0x1b0
 blk_mq_freeze_queue_wait+0x9d/0xf0
 ? ipi_rseq+0x70/0x70
 blk_mq_freeze_queue+0x2b/0x40
 nbd_add_socket+0x6b/0x270 [nbd]
 nbd_ioctl+0x383/0x510 [nbd]
 blkdev_ioctl+0x18e/0x3e0
 __x64_sys_ioctl+0xac/0x120
 do_syscall_64+0x35/0x80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fd8ff706577
RSP: 002b:00007fd8fcdfebf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000040000000 RCX: 00007fd8ff706577
RDX: 000000000000000d RSI: 000000000000ab00 RDI: 000000000000000f
RBP: 000000000000000f R08: 000000000000fbe8 R09: 000055fe497c62b0
R10: 00000002aff20000 R11: 0000000000000246 R12: 000000000000006d
R13: 0000000000000000 R14: 00007ffe82dc5e70 R15: 00007fd8fcdff9c0

"qemu-ndb -d" will call ioctl 'NBD_DISCONNECT' first, however, following
message was found:

block nbd0: Send disconnect failed -32

Which indicate that something is wrong with the server. Then,
"qemu-nbd -d" will call ioctl 'NBD_CLEAR_SOCK', however ioctl can't clear
requests after commit 2516ab1543fd("nbd: only clear the queue on device
teardown"). And in the meantime, request can't complete through timeout
because nbd_xmit_timeout() will always return 'BLK_EH_RESET_TIMER', which
means such request will never be completed in this situation.

Now that the flag 'NBD_CMD_INFLIGHT' can make sure requests won't
complete multiple times, switch back to call nbd_clear_sock() in
nbd_clear_sock_ioctl(), so that inflight requests can be cleared.

Signed-off-by: Yu Kuai 
Reviewed-by: Josef Bacik 
Link: https://lore.kernel.org/r/20220521073749.3146892-5-yukuai3@huawei.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

nbd: fix race between nbd_alloc_config() and module removal

2022-06-14T16:12:01+00:00

[ Upstream commit c55b2b983b0fa012942c3eb16384b2b722caa810 ]

When nbd module is being removing, nbd_alloc_config() may be
called concurrently by nbd_genl_connect(), although try_module_get()
will return false, but nbd_alloc_config() doesn't handle it.

The race may lead to the leak of nbd_config and its related
resources (e.g, recv_workq) and oops in nbd_read_stat() due
to the unload of nbd module as shown below:

  BUG: kernel NULL pointer dereference, address: 0000000000000040
  Oops: 0000 [#1] SMP PTI
  CPU: 5 PID: 13840 Comm: kworker/u17:33 Not tainted 5.14.0+ #1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
  Workqueue: knbd16-recv recv_work [nbd]
  RIP: 0010:nbd_read_stat.cold+0x130/0x1a4 [nbd]
  Call Trace:
   recv_work+0x3b/0xb0 [nbd]
   process_one_work+0x1ed/0x390
   worker_thread+0x4a/0x3d0
   kthread+0x12a/0x150
   ret_from_fork+0x22/0x30

Fixing it by checking the return value of try_module_get()
in nbd_alloc_config(). As nbd_alloc_config() may return ERR_PTR(-ENODEV),
assign nbd->config only when nbd_alloc_config() succeeds to ensure
the value of nbd->config is binary (valid or NULL).

Also adding a debug message to check the reference counter
of nbd_config during module removal.

Signed-off-by: Hou Tao 
Signed-off-by: Yu Kuai 
Reviewed-by: Josef Bacik 
Link: https://lore.kernel.org/r/20220521073749.3146892-3-yukuai3@huawei.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

nbd: call genl_unregister_family() first in nbd_cleanup()

2022-06-14T16:12:01+00:00

[ Upstream commit 06c4da89c24e7023ea448cadf8e9daf06a0aae6e ]

Otherwise there may be race between module removal and the handling of
netlink command, which can lead to the oops as shown below:

  BUG: kernel NULL pointer dereference, address: 0000000000000098
  Oops: 0002 [#1] SMP PTI
  CPU: 1 PID: 31299 Comm: nbd-client Tainted: G            E     5.14.0-rc4
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
  RIP: 0010:down_write+0x1a/0x50
  Call Trace:
   start_creating+0x89/0x130
   debugfs_create_dir+0x1b/0x130
   nbd_start_device+0x13d/0x390 [nbd]
   nbd_genl_connect+0x42f/0x748 [nbd]
   genl_family_rcv_msg_doit.isra.0+0xec/0x150
   genl_rcv_msg+0xe5/0x1e0
   netlink_rcv_skb+0x55/0x100
   genl_rcv+0x29/0x40
   netlink_unicast+0x1a8/0x250
   netlink_sendmsg+0x21b/0x430
   ____sys_sendmsg+0x2a4/0x2d0
   ___sys_sendmsg+0x81/0xc0
   __sys_sendmsg+0x62/0xb0
   __x64_sys_sendmsg+0x1f/0x30
   do_syscall_64+0x3b/0xc0
   entry_SYSCALL_64_after_hwframe+0x44/0xae
  Modules linked in: nbd(E-)

Signed-off-by: Hou Tao 
Signed-off-by: Yu Kuai 
Reviewed-by: Josef Bacik 
Link: https://lore.kernel.org/r/20220521073749.3146892-2-yukuai3@huawei.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

virtio_blk: fix the discard_granularity and discard_alignment queue limits

2022-06-14T16:11:35+00:00

[ Upstream commit 62952cc5bccd89b76d710de1d0b43244af0f2903 ]

The discard_alignment queue limit is named a bit misleading means the
offset into the block device at which the discard granularity starts.

On the other hand the discard_sector_alignment from the virtio 1.1 looks
similar to what Linux uses as discard granularity (even if not very well
described):

  "discard_sector_alignment can be used by OS when splitting a request
   based on alignment. "

And at least qemu does set it to the discard granularity.

So stop setting the discard_alignment and use the virtio
discard_sector_alignment to set the discard granularity.

Fixes: 1f23816b8eb8 ("virtio_blk: add discard and write zeroes support")
Signed-off-by: Christoph Hellwig 
Reviewed-by: Martin K. Petersen 
Link: https://lore.kernel.org/r/20220418045314.360785-5-hch@lst.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

drbd: fix duplicate array initializer

2022-06-14T16:11:33+00:00

[ Upstream commit 33cb0917bbe241dd17a2b87ead63514c1b7e5615 ]

There are two initializers for P_RETRY_WRITE:

drivers/block/drbd/drbd_main.c:3676:22: warning: initialized field overwritten [-Woverride-init]

Remove the first one since it was already ignored by the compiler
and reorder the list to match the enum definition. As P_ZEROES had
no entry, add that one instead.

Fixes: 036b17eaab93 ("drbd: Receiving part for the PROTOCOL_UPDATE packet")
Fixes: f31e583aa2c2 ("drbd: introduce P_ZEROES (REQ_OP_WRITE_ZEROES on the "wire")")
Signed-off-by: Arnd Bergmann 
Reviewed-by: Christoph Böhmwalder 
Link: https://lore.kernel.org/r/20220406190715.1938174-2-christoph.boehmwalder@linbit.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

nbd: Fix hung on disconnect request if socket is closed before

2022-06-14T16:11:28+00:00

[ Upstream commit 491bf8f236fdeec698fa6744993f1ecf3fafd1a5 ]

When userspace closes the socket before sending a disconnect
request, the following I/O requests will be blocked in
wait_for_reconnect() until dead timeout. This will cause the
following disconnect request also hung on blk_mq_quiesce_queue().
That means we have no way to disconnect a nbd device if there
are some I/O requests waiting for reconnecting until dead timeout.
It's not expected. So let's wake up the thread waiting for
reconnecting directly when a disconnect request is sent.

Reported-by: Xu Jianhai 
Signed-off-by: Xie Yongji 
Reviewed-by: Josef Bacik 
Link: https://lore.kernel.org/r/20220322080639.142-1-xieyongji@bytedance.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

drbd: remove usage of list iterator variable after loop

2022-05-25T07:14:32+00:00

[ Upstream commit 901aeda62efa21f2eae937bccb71b49ae531be06 ]

In preparation to limit the scope of a list iterator to the list
traversal loop, use a dedicated pointer to iterate through the list [1].

Since that variable should not be used past the loop iteration, a
separate variable is used to 'remember the current location within the
loop'.

To either continue iterating from that position or skip the iteration
(if the previous iteration was complete) list_prepare_entry() is used.

Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1]
Signed-off-by: Jakob Koschel 
Link: https://lore.kernel.org/r/20220331220349.885126-1-jakobkoschel@gmail.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

floppy: use a statically allocated error counter

2022-05-25T07:14:31+00:00

commit f71f01394f742fc4558b3f9f4c7ef4c4cf3b07c8 upstream.

Interrupt handler bad_flp_intr() may cause a UAF on the recently freed
request just to increment the error count.  There's no point keeping
that one in the request anyway, and since the interrupt handler uses a
static pointer to the error which cannot be kept in sync with the
pending request, better make it use a static error counter that's reset
for each new request.  This reset now happens when entering
redo_fd_request() for a new request via set_next_request().

One initial concern about a single error counter was that errors on one
floppy drive could be reported on another one, but this problem is not
real given that the driver uses a single drive at a time, as that
PC-compatible controllers also have this limitation by using shared
signals.  As such the error count is always for the "current" drive.

Reported-by: Minh Yuan 
Suggested-by: Linus Torvalds 
Tested-by: Denis Efremov 
Signed-off-by: Willy Tarreau 
Signed-off-by: Linus Torvalds 
Signed-off-by: Denis Efremov 
Signed-off-by: Greg Kroah-Hartman

block: drbd: drbd_nl: Make conversion to 'enum drbd_ret_code' explicit

2022-05-15T17:54:46+00:00

commit 1f1e87b4dc4598eac57a69868534b92d65e47e82 upstream.

Fixes the following W=1 kernel build warning(s):

 from drivers/block/drbd/drbd_nl.c:24:
 drivers/block/drbd/drbd_nl.c: In function ‘drbd_adm_set_role’:
 drivers/block/drbd/drbd_nl.c:793:11: warning: implicit conversion from ‘enum drbd_state_rv’ to ‘enum drbd_ret_code’ [-Wenum-conversion]
 drivers/block/drbd/drbd_nl.c:795:11: warning: implicit conversion from ‘enum drbd_state_rv’ to ‘enum drbd_ret_code’ [-Wenum-conversion]
 drivers/block/drbd/drbd_nl.c: In function ‘drbd_adm_attach’:
 drivers/block/drbd/drbd_nl.c:1965:10: warning: implicit conversion from ‘enum drbd_state_rv’ to ‘enum drbd_ret_code’ [-Wenum-conversion]
 drivers/block/drbd/drbd_nl.c: In function ‘drbd_adm_connect’:
 drivers/block/drbd/drbd_nl.c:2690:10: warning: implicit conversion from ‘enum drbd_state_rv’ to ‘enum drbd_ret_code’ [-Wenum-conversion]
 drivers/block/drbd/drbd_nl.c: In function ‘drbd_adm_disconnect’:
 drivers/block/drbd/drbd_nl.c:2803:11: warning: implicit conversion from ‘enum drbd_state_rv’ to ‘enum drbd_ret_code’ [-Wenum-conversion]

Cc: Philipp Reisner 
Cc: Lars Ellenberg 
Cc: Jens Axboe 
Cc: drbd-dev@lists.linbit.com
Cc: linux-block@vger.kernel.org
Signed-off-by: Lee Jones 
Link: https://lore.kernel.org/r/20210312105530.2219008-8-lee.jones@linaro.org
Signed-off-by: Jens Axboe 
Cc: Nathan Chancellor 
Signed-off-by: Greg Kroah-Hartman

floppy: disable FDRAWCMD by default

2022-05-09T07:03:20+00:00

commit 233087ca063686964a53c829d547c7571e3f67bf upstream.

Minh Yuan reported a concurrency use-after-free issue in the floppy code
between raw_cmd_ioctl and seek_interrupt.

[ It turns out this has been around, and that others have reported the
  KASAN splats over the years, but Minh Yuan had a reproducer for it and
  so gets primary credit for reporting it for this fix   - Linus ]

The problem is, this driver tends to break very easily and nowadays,
nobody is expected to use FDRAWCMD anyway since it was used to
manipulate non-standard formats.  The risk of breaking the driver is
higher than the risk presented by this race, and accessing the device
requires privileges anyway.

Let's just add a config option to completely disable this ioctl and
leave it disabled by default.  Distros shouldn't use it, and only those
running on antique hardware might need to enable it.

Link: https://lore.kernel.org/all/000000000000b71cdd05d703f6bf@google.com/
Link: https://lore.kernel.org/lkml/CAKcFiNC=MfYVW-Jt9A3=FPJpTwCD2PL_ULNCpsCVE5s8ZeBQgQ@mail.gmail.com
Link: https://lore.kernel.org/all/CAEAjamu1FRhz6StCe_55XY5s389ZP_xmCF69k987En+1z53=eg@mail.gmail.com
Reported-by: Minh Yuan 
Reported-by: syzbot+8e8958586909d62b6840@syzkaller.appspotmail.com
Reported-by: cruise k 
Reported-by: Kyungtae Kim 
Suggested-by: Linus Torvalds 
Tested-by: Denis Efremov 
Signed-off-by: Willy Tarreau 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman