linux-toradex.git/drivers/block, branch v4.9.96

block/loop: fix deadlock after loop_set_status

2018-04-20T06:21:06+00:00

commit 1e047eaab3bb5564f25b41e9cd3a053009f4e789 upstream.

syzbot is reporting deadlocks at __blkdev_get() [1].

----------------------------------------
[   92.493919] systemd-udevd   D12696   525      1 0x00000000
[   92.495891] Call Trace:
[   92.501560]  schedule+0x23/0x80
[   92.502923]  schedule_preempt_disabled+0x5/0x10
[   92.504645]  __mutex_lock+0x416/0x9e0
[   92.510760]  __blkdev_get+0x73/0x4f0
[   92.512220]  blkdev_get+0x12e/0x390
[   92.518151]  do_dentry_open+0x1c3/0x2f0
[   92.519815]  path_openat+0x5d9/0xdc0
[   92.521437]  do_filp_open+0x7d/0xf0
[   92.527365]  do_sys_open+0x1b8/0x250
[   92.528831]  do_syscall_64+0x6e/0x270
[   92.530341]  entry_SYSCALL_64_after_hwframe+0x42/0xb7

[   92.931922] 1 lock held by systemd-udevd/525:
[   92.933642]  #0: 00000000a2849e25 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x73/0x4f0
----------------------------------------

The reason of deadlock turned out that wait_event_interruptible() in
blk_queue_enter() got stuck with bdev->bd_mutex held at __blkdev_put()
due to q->mq_freeze_depth == 1.

----------------------------------------
[   92.787172] a.out           S12584   634    633 0x80000002
[   92.789120] Call Trace:
[   92.796693]  schedule+0x23/0x80
[   92.797994]  blk_queue_enter+0x3cb/0x540
[   92.803272]  generic_make_request+0xf0/0x3d0
[   92.807970]  submit_bio+0x67/0x130
[   92.810928]  submit_bh_wbc+0x15e/0x190
[   92.812461]  __block_write_full_page+0x218/0x460
[   92.815792]  __writepage+0x11/0x50
[   92.817209]  write_cache_pages+0x1ae/0x3d0
[   92.825585]  generic_writepages+0x5a/0x90
[   92.831865]  do_writepages+0x43/0xd0
[   92.836972]  __filemap_fdatawrite_range+0xc1/0x100
[   92.838788]  filemap_write_and_wait+0x24/0x70
[   92.840491]  __blkdev_put+0x69/0x1e0
[   92.841949]  blkdev_close+0x16/0x20
[   92.843418]  __fput+0xda/0x1f0
[   92.844740]  task_work_run+0x87/0xb0
[   92.846215]  do_exit+0x2f5/0xba0
[   92.850528]  do_group_exit+0x34/0xb0
[   92.852018]  SyS_exit_group+0xb/0x10
[   92.853449]  do_syscall_64+0x6e/0x270
[   92.854944]  entry_SYSCALL_64_after_hwframe+0x42/0xb7

[   92.943530] 1 lock held by a.out/634:
[   92.945105]  #0: 00000000a2849e25 (&bdev->bd_mutex){+.+.}, at: __blkdev_put+0x3c/0x1e0
----------------------------------------

The reason of q->mq_freeze_depth == 1 turned out that loop_set_status()
forgot to call blk_mq_unfreeze_queue() at error paths for
info->lo_encrypt_type != NULL case.

----------------------------------------
[   37.509497] CPU: 2 PID: 634 Comm: a.out Tainted: G        W        4.16.0+ #457
[   37.513608] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/19/2017
[   37.518832] RIP: 0010:blk_freeze_queue_start+0x17/0x40
[   37.521778] RSP: 0018:ffffb0c2013e7c60 EFLAGS: 00010246
[   37.524078] RAX: 0000000000000000 RBX: ffff8b07b1519798 RCX: 0000000000000000
[   37.527015] RDX: 0000000000000002 RSI: ffffb0c2013e7cc0 RDI: ffff8b07b1519798
[   37.529934] RBP: ffffb0c2013e7cc0 R08: 0000000000000008 R09: 47a189966239b898
[   37.532684] R10: dad78b99b278552f R11: 9332dca72259d5ef R12: ffff8b07acd73678
[   37.535452] R13: 0000000000004c04 R14: 0000000000000000 R15: ffff8b07b841e940
[   37.538186] FS:  00007fede33b9740(0000) GS:ffff8b07b8e80000(0000) knlGS:0000000000000000
[   37.541168] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   37.543590] CR2: 00000000206fdf18 CR3: 0000000130b30006 CR4: 00000000000606e0
[   37.546410] Call Trace:
[   37.547902]  blk_freeze_queue+0x9/0x30
[   37.549968]  loop_set_status+0x67/0x3c0 [loop]
[   37.549975]  loop_set_status64+0x3b/0x70 [loop]
[   37.549986]  lo_ioctl+0x223/0x810 [loop]
[   37.549995]  blkdev_ioctl+0x572/0x980
[   37.550003]  block_ioctl+0x34/0x40
[   37.550006]  do_vfs_ioctl+0xa7/0x6d0
[   37.550017]  ksys_ioctl+0x6b/0x80
[   37.573076]  SyS_ioctl+0x5/0x10
[   37.574831]  do_syscall_64+0x6e/0x270
[   37.576769]  entry_SYSCALL_64_after_hwframe+0x42/0xb7
----------------------------------------

[1] https://syzkaller.appspot.com/bug?id=cd662bc3f6022c0979d01a262c318fab2ee9b56f

Signed-off-by: Tetsuo Handa 
Reported-by: syzbot 
Fixes: ecdd09597a572513 ("block/loop: fix race between I/O and set_status")
Cc: Ming Lei 
Cc: Dmitry Vyukov 
Cc: stable 
Cc: Jens Axboe 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

Fix loop device flush before configure v3

2018-04-13T17:48:24+00:00

[ Upstream commit 6460495709aeb651896bc8e5c134b2e4ca7d34a8 ]

While installing SLES-12 (based on v4.4), I found that the installer
will stall for 60+ seconds during LVM disk scan.  The root cause was
determined to be the removal of a bound device check in loop_flush()
by commit b5dd2f6047ca ("block: loop: improve performance via blk-mq").

Restoring this check, examining ->lo_state as set by loop_set_fd()
eliminates the bad behavior.

Test method:
modprobe loop max_loop=64
dd if=/dev/zero of=disk bs=512 count=200K
for((i=0;i<4;i++))do losetup -f disk; done
mkfs.ext4 -F /dev/loop0
for((i=0;i<4;i++))do mkdir t$i; mount /dev/loop$i t$i;done
for f in `ls /dev/loop[0-9]*|sort`; do \
	echo $f; dd if=$f of=/dev/null  bs=512 count=1; \
	done

Test output:  stock          patched
/dev/loop0    18.1217e-05    8.3842e-05
/dev/loop1     6.1114e-05    0.000147979
/dev/loop10    0.414701      0.000116564
/dev/loop11    0.7474        6.7942e-05
/dev/loop12    0.747986      8.9082e-05
/dev/loop13    0.746532      7.4799e-05
/dev/loop14    0.480041      9.3926e-05
/dev/loop15    1.26453       7.2522e-05

Note that from loop10 onward, the device is not mounted, yet the
stock kernel consumes several orders of magnitude more wall time
than it does for a mounted device.
(Thanks for Mike Galbraith , give a changelog review.)

Reviewed-by: Hannes Reinecke 
Reviewed-by: Ming Lei 
Signed-off-by: James Wang 
Fixes: b5dd2f6047ca ("block: loop: improve performance via blk-mq")
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

Revert "mtip32xx: use runtime tag to initialize command header"

2018-04-08T10:13:01+00:00

This reverts commit db54facd56a40e7766bf7f7cda1ae138e72a691c which was
commit a4e84aae8139aca9fbfbced1f45c51ca81b57488 upstream.

Ben writes:
    MQ IO schedulers were introduced in 4.11, so this shouldn't be
    needed in older branches.  It also causes a performance
    regression (fixed upstream).  Please revert this for 4.4 and
    4.9.

So let's revert it!

Reported-by: Ben Hutchings 
Cc: Ming Lei 
Cc: Jens Axboe 
Cc: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

mtip32xx: use runtime tag to initialize command header

2018-03-24T10:00:17+00:00

[ Upstream commit a4e84aae8139aca9fbfbced1f45c51ca81b57488 ]

mtip32xx supposes that 'request_idx' passed to .init_request()
is tag of the request, and use that as request's tag to initialize
command header.

After MQ IO scheduler is in, request tag assigned isn't same with
the request index anymore, so cause strange hardware failure on
mtip32xx, even whole system panic is triggered.

This patch fixes the issue by initializing command header via
request's real tag.

Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

loop: Fix lost writes caused by missing flag

2018-03-18T10:18:50+00:00

commit 1d037577c323e5090ce281e96bc313ab2eee5be2 upstream.

The following commit:

commit aa4d86163e4e ("block: loop: switch to VFS ITER_BVEC")

replaced __do_lo_send_write(), which used ITER_KVEC iterators, with
lo_write_bvec() which uses ITER_BVEC iterators.  In this change, though,
the WRITE flag was lost:

-       iov_iter_kvec(&from, ITER_KVEC | WRITE, &kvec, 1, len);
+       iov_iter_bvec(&i, ITER_BVEC, bvec, 1, bvec->bv_len);

This flag is necessary for the DAX case because we make decisions based on
whether or not the iterator is a READ or a WRITE in dax_iomap_actor() and
in dax_iomap_rw().

We end up going through this path in configurations where we combine a PMEM
device with 4k sectors, a loopback device and DAX.  The consequence of this
missed flag is that what we intend as a write actually turns into a read in
the DAX code, so no data is ever written.

The very simplest test case is to create a loopback device and try and
write a small string to it, then hexdump a few bytes of the device to see
if the write took.  Without this patch you read back all zeros, with this
you read back the string you wrote.

For XFS this causes us to fail or panic during the following xfstests:

	xfs/074 xfs/078 xfs/216 xfs/217 xfs/250

For ext4 we have a similar issue where writes never happen, but we don't
currently have any xfstests that use loopback and show this issue.

Fix this by restoring the WRITE flag argument to iov_iter_bvec().  This
causes the xfstests to all pass.

Cc: Al Viro 
Cc: stable@vger.kernel.org
Fixes: commit aa4d86163e4e ("block: loop: switch to VFS ITER_BVEC")
Reviewed-by: Christoph Hellwig 
Reviewed-by: Ming Lei 
Signed-off-by: Ross Zwisler 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

rbd: silence bogus -Wmaybe-uninitialized warning

2018-02-25T10:05:54+00:00

commit d4c2269b3d5d06a8ea434b1841fbcaec336ed396 upstream.

drivers/block/rbd.c: In function ‘rbd_watch_cb’:
drivers/block/rbd.c:3690:5: error: ‘struct_v’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/block/rbd.c:3759:5: note: ‘struct_v’ was declared here

Signed-off-by: Ilya Dryomov 
Signed-off-by: Greg Kroah-Hartman

pktcdvd: Fix pkt_setup_dev() error path

2018-02-17T12:21:19+00:00

commit 5a0ec388ef0f6e33841aeb810d7fa23f049ec4cd upstream.

Commit 523e1d399ce0 ("block: make gendisk hold a reference to its queue")
modified add_disk() and disk_release() but did not update any of the
error paths that trigger a put_disk() call after disk->queue has been
assigned. That introduced the following behavior in the pktcdvd driver
if pkt_new_dev() fails:

Kernel BUG at 00000000e98fd882 [verbose debug info unavailable]

Since disk_release() calls blk_put_queue() anyway if disk->queue != NULL,
fix this by removing the blk_cleanup_queue() call from the pkt_setup_dev()
error path.

Fixes: commit 523e1d399ce0 ("block: make gendisk hold a reference to its queue")
Signed-off-by: Bart Van Assche 
Cc: Tejun Heo 
Cc: Maciej S. Szmigiero 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

loop: fix concurrent lo_open/lo_release

2018-02-03T16:05:33+00:00

commit ae6650163c66a7eff1acd6eb8b0f752dcfa8eba5 upstream.

范龙飞 reports that KASAN can report a use-after-free in __lock_acquire.
The reason is due to insufficient serialization in lo_release(), which
will continue to use the loop device even after it has decremented the
lo_refcnt to zero.

In the meantime, another process can come in, open the loop device
again as it is being shut down. Confusion ensues.

Reported-by: 范龙飞 
Signed-off-by: Linus Torvalds 
Signed-off-by: Jens Axboe 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

rbd: set max_segments to USHRT_MAX

2018-01-17T08:38:54+00:00

commit 21acdf45f4958135940f0b4767185cf911d4b010 upstream.

Commit d3834fefcfe5 ("rbd: bump queue_max_segments") bumped
max_segments (unsigned short) to max_hw_sectors (unsigned int).
max_hw_sectors is set to the number of 512-byte sectors in an object
and overflows unsigned short for 32M (largest possible) objects, making
the block layer resort to handing us single segment (i.e. single page
or even smaller) bios in that case.

Fixes: d3834fefcfe5 ("rbd: bump queue_max_segments")
Signed-off-by: Ilya Dryomov 
Reviewed-by: Alex Elder 
Signed-off-by: Greg Kroah-Hartman

nbd: fix use-after-free of rq/bio in the xmit path

2018-01-10T08:29:52+00:00

commit 429a787be6793554ee02aacc7e1f11ebcecc4453 upstream.

For writes, we can get a completion in while we're still iterating
the request and bio chain. If that happens, we're reading freed
memory and we can crash.

Break out after the last segment and avoid having the iterator
read freed memory.

Reviewed-by: Josef Bacik 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman