linux-stable.git/drivers/block, branch v5.4.26

virtio-blk: fix hw_queue stopped on arbitrary error

2020-03-18T06:17:48+00:00

commit f5f6b95c72f7f8bb46eace8c5306c752d0133daa upstream.

Since nobody else is going to restart our hw_queue for us, the
blk_mq_start_stopped_hw_queues() is in virtblk_done() is not sufficient
necessarily sufficient to ensure that the queue will get started again.
In case of global resource outage (-ENOMEM because mapping failure,
because of swiotlb full) our virtqueue may be empty and we can get
stuck with a stopped hw_queue.

Let us not stop the queue on arbitrary errors, but only on -EONSPC which
indicates a full virtqueue, where the hw_queue is guaranteed to get
started by virtblk_done() before when it makes sense to carry on
submitting requests. Let us also remove a stale comment.

Signed-off-by: Halil Pasic 
Cc: Jens Axboe 
Fixes: f7728002c1c7 ("virtio_ring: fix return code on DMA mapping fails")
Link: https://lore.kernel.org/r/20200213123728.61216-2-pasic@linux.ibm.com
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Stefan Hajnoczi 
Signed-off-by: Greg Kroah-Hartman

floppy: check FDC index for errors before assigning it

2020-02-28T16:22:14+00:00

commit 2e90ca68b0d2f5548804f22f0dd61145516171e3 upstream.

Jordy Zomer reported a KASAN out-of-bounds read in the floppy driver in
wait_til_ready().

Which on the face of it can't happen, since as Willy Tarreau points out,
the function does no particular memory access.  Except through the FDCS
macro, which just indexes a static allocation through teh current fdc,
which is always checked against N_FDC.

Except the checking happens after we've already assigned the value.

The floppy driver is a disgrace (a lot of it going back to my original
horrd "design"), and has no real maintainer.  Nobody has the hardware,
and nobody really cares.  But it still gets used in virtual environment
because it's one of those things that everybody supports.

The whole thing should be re-written, or at least parts of it should be
seriously cleaned up.  The 'current fdc' index, which is used by the
FDCS macro, and which is often shadowed by a local 'fdc' variable, is a
prime example of how not to write code.

But because nobody has the hardware or the motivation, let's just fix up
the immediate problem with a nasty band-aid: test the fdc index before
actually assigning it to the static 'fdc' variable.

Reported-by: Jordy Zomer 
Cc: Willy Tarreau 
Cc: Dan Carpenter 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

brd: check and limit max_part par

2020-02-24T07:37:02+00:00

[ Upstream commit c8ab422553c81a0eb070329c63725df1cd1425bc ]

In brd_init func, rd_nr num of brd_device are firstly allocated
and add in brd_devices, then brd_devices are traversed to add each
brd_device by calling add_disk func. When allocating brd_device,
the disk->first_minor is set to i * max_part, if rd_nr * max_part
is larger than MINORMASK, two different brd_device may have the same
devt, then only one of them can be successfully added.
when rmmod brd.ko, it will cause oops when calling brd_exit.

Follow those steps:
  # modprobe brd rd_nr=3 rd_size=102400 max_part=1048576
  # rmmod brd
then, the oops will appear.

Oops log:
[  726.613722] Call trace:
[  726.614175]  kernfs_find_ns+0x24/0x130
[  726.614852]  kernfs_find_and_get_ns+0x44/0x68
[  726.615749]  sysfs_remove_group+0x38/0xb0
[  726.616520]  blk_trace_remove_sysfs+0x1c/0x28
[  726.617320]  blk_unregister_queue+0x98/0x100
[  726.618105]  del_gendisk+0x144/0x2b8
[  726.618759]  brd_exit+0x68/0x560 [brd]
[  726.619501]  __arm64_sys_delete_module+0x19c/0x2a0
[  726.620384]  el0_svc_common+0x78/0x130
[  726.621057]  el0_svc_handler+0x38/0x78
[  726.621738]  el0_svc+0x8/0xc
[  726.622259] Code: aa0203f6 aa0103f7 aa1e03e0 d503201f (7940e260)

Here, we add brd_check_and_reset_par func to check and limit max_part par.

--
V5->V6:
 - remove useless code

V4->V5:(suggested by Ming Lei)
 - make sure max_part is not larger than DISK_MAX_PARTS

V3->V4:(suggested by Ming Lei)
 - remove useless change
 - add one limit of max_part

V2->V3: (suggested by Ming Lei)
 - clear .minors when running out of consecutive minor space in brd_alloc
 - remove limit of rd_nr

V1->V2:
 - add more checks in brd_check_par_valid as suggested by Ming Lei.

Signed-off-by: Zhiqiang Liu 
Reviewed-by: Bob Liu 
Reviewed-by: Ming Lei 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

rbd: work around -Wuninitialized warning

2020-02-24T07:36:59+00:00

[ Upstream commit a55e601b2f02df5db7070e9a37bd655c9c576a52 ]

gcc -O3 warns about a dummy variable that is passed
down into rbd_img_fill_nodata without being initialized:

drivers/block/rbd.c: In function 'rbd_img_fill_nodata':
drivers/block/rbd.c:2573:13: error: 'dummy' is used uninitialized in this function [-Werror=uninitialized]
  fctx->iter = *fctx->pos;

Since this is a dummy, I assume the warning is harmless, but
it's better to initialize it anyway and avoid the warning.

Fixes: mmtom ("init/Kconfig: enable -O3 for all arches")
Signed-off-by: Arnd Bergmann 
Reviewed-by: Ilya Dryomov 
Signed-off-by: Ilya Dryomov 
Signed-off-by: Sasha Levin

drivers/block/zram/zram_drv.c: fix error return codes not being returned in writeback_store

2020-02-24T07:36:31+00:00

[ Upstream commit 3b82a051c10143639a378dcd12019f2353cc9054 ]

Currently when an error code -EIO or -ENOSPC in the for-loop of
writeback_store the error code is being overwritten by a ret = len
assignment at the end of the function and the error codes are being
lost.  Fix this by assigning ret = len at the start of the function and
remove the assignment from the end, hence allowing ret to be preserved
when error codes are assigned to it.

Addresses Coverity ("Unused value")

Link: http://lkml.kernel.org/r/20191128122958.178290-1-colin.king@canonical.com
Fixes: a939888ec38b ("zram: support idle/huge page writeback")
Signed-off-by: Colin Ian King 
Acked-by: Minchan Kim 
Cc: Sergey Senozhatsky 
Cc: Jens Axboe 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

nbd: add a flush_workqueue in nbd_start_device

2020-02-24T07:36:31+00:00

[ Upstream commit 5c0dd228b5fc30a3b732c7ae2657e0161ec7ed80 ]

When kzalloc fail, may cause trying to destroy the
workqueue from inside the workqueue.

If num_connections is m (2 < m), and NO.1 ~ NO.n
(1 < n < m) kzalloc are successful. The NO.(n + 1)
failed. Then, nbd_start_device will return ENOMEM
to nbd_start_device_ioctl, and nbd_start_device_ioctl
will return immediately without running flush_workqueue.
However, we still have n recv threads. If nbd_release
run first, recv threads may have to drop the last
config_refs and try to destroy the workqueue from
inside the workqueue.

To fix it, add a flush_workqueue in nbd_start_device.

Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs")
Signed-off-by: Sun Ke 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

xen/blkfront: Adjust indentation in xlvbd_alloc_gendisk

2020-01-23T07:22:54+00:00

commit 589b72894f53124a39d1bb3c0cecaf9dcabac417 upstream.

Clang warns:

../drivers/block/xen-blkfront.c:1117:4: warning: misleading indentation;
statement is not part of the previous 'if' [-Wmisleading-indentation]
                nr_parts = PARTS_PER_DISK;
                ^
../drivers/block/xen-blkfront.c:1115:3: note: previous statement is here
                if (err)
                ^

This is because there is a space at the beginning of this line; remove
it so that the indentation is consistent according to the Linux kernel
coding style and clang no longer warns.

While we are here, the previous line has some trailing whitespace; clean
that up as well.

Fixes: c80a420995e7 ("xen-blkfront: handle Xen major numbers other than XENVBD")
Link: https://github.com/ClangBuiltLinux/linux/issues/791
Signed-off-by: Nathan Chancellor 
Reviewed-by: Juergen Gross 
Acked-by: Roger Pau Monné 
Signed-off-by: Juergen Gross 
Signed-off-by: Greg Kroah-Hartman

xen/blkback: Avoid unmapping unmapped grant pages

2020-01-09T09:20:07+00:00

[ Upstream commit f9bd84a8a845d82f9b5a081a7ae68c98a11d2e84 ]

For each I/O request, blkback first maps the foreign pages for the
request to its local pages.  If an allocation of a local page for the
mapping fails, it should unmap every mapping already made for the
request.

However, blkback's handling mechanism for the allocation failure does
not mark the remaining foreign pages as unmapped.  Therefore, the unmap
function merely tries to unmap every valid grant page for the request,
including the pages not mapped due to the allocation failure.  On a
system that fails the allocation frequently, this problem leads to
following kernel crash.

  [  372.012538] BUG: unable to handle kernel NULL pointer dereference at 0000000000000001
  [  372.012546] IP: [] gnttab_unmap_refs.part.7+0x1c/0x40
  [  372.012557] PGD 16f3e9067 PUD 16426e067 PMD 0
  [  372.012562] Oops: 0002 [#1] SMP
  [  372.012566] Modules linked in: act_police sch_ingress cls_u32
  ...
  [  372.012746] Call Trace:
  [  372.012752]  [] gnttab_unmap_refs+0x34/0x40
  [  372.012759]  [] xen_blkbk_unmap+0x83/0x150 [xen_blkback]
  ...
  [  372.012802]  [] dispatch_rw_block_io+0x970/0x980 [xen_blkback]
  ...
  Decompressing Linux... Parsing ELF... done.
  Booting the kernel.
  [    0.000000] Initializing cgroup subsys cpuset

This commit fixes this problem by marking the grant pages of the given
request that didn't mapped due to the allocation failure as invalid.

Fixes: c6cc142dac52 ("xen-blkback: use balloon pages for all mappings")

Reviewed-by: David Woodhouse 
Reviewed-by: Maximilian Heyne 
Reviewed-by: Paul Durrant 
Reviewed-by: Roger Pau Monné 
Signed-off-by: SeongJae Park 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

xen-blkback: prevent premature module unload

2020-01-09T09:19:51+00:00

[ Upstream commit fa2ac657f9783f0891b2935490afe9a7fd29d3fa ]

Objects allocated by xen_blkif_alloc come from the 'blkif_cache' kmem
cache. This cache is destoyed when xen-blkif is unloaded so it is
necessary to wait for the deferred free routine used for such objects to
complete. This necessity was missed in commit 14855954f636 "xen-blkback:
allow module to be cleanly unloaded". This patch fixes the problem by
taking/releasing extra module references in xen_blkif_alloc/free()
respectively.

Signed-off-by: Paul Durrant 
Reviewed-by: Roger Pau Monné 
Signed-off-by: Juergen Gross 
Signed-off-by: Sasha Levin

nbd: fix shutdown and recv work deadlock v2

2019-12-31T15:46:34+00:00

commit 1c05839aa973cfae8c3db964a21f9c0eef8fcc21 upstream.

This fixes a regression added with:

commit e9e006f5fcf2bab59149cb38a48a4817c1b538b4
Author: Mike Christie 
Date:   Sun Aug 4 14:10:06 2019 -0500

    nbd: fix max number of supported devs

where we can deadlock during device shutdown. The problem occurs if
the recv_work's nbd_config_put occurs after nbd_start_device_ioctl has
returned and the userspace app has droppped its reference via closing
the device and running nbd_release. The recv_work nbd_config_put call
would then drop the refcount to zero and try to destroy the config which
would try to do destroy_workqueue from the recv work.

This patch just has nbd_start_device_ioctl do a flush_workqueue when it
wakes so we know after the ioctl returns running works have exited. This
also fixes a possible race where we could try to reuse the device while
old recv_works are still running.

Cc: stable@vger.kernel.org
Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs")
Signed-off-by: Mike Christie 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman