linux-stable.git/drivers/block, branch v4.14.65 Linux kernel stable tree loop: remember whether sysfs_create_group() was done 2018-07-17T09:39:33+00:00 Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp 2018-05-04T16:58:09+00:00 d2c18ad18cc7041b0591847d4c4ea4802bbd122e commit d3349b6b3c373ac1fbfb040b810fcee5e2adc7e0 upstream. syzbot is hitting WARN() triggered by memory allocation fault injection [1] because loop module is calling sysfs_remove_group() when sysfs_create_group() failed. Fix this by remembering whether sysfs_create_group() succeeded. [1] https://syzkaller.appspot.com/bug?id=3f86c0edf75c86d2633aeb9dd69eccc70bc7e90b Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reported-by: syzbot <syzbot+9f03168400f56df89dbc6f1751f4458fe739ff29@syzkaller.appspotmail.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Renamed sysfs_ready -> sysfs_inited. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit d3349b6b3c373ac1fbfb040b810fcee5e2adc7e0 upstream.

syzbot is hitting WARN() triggered by memory allocation fault
injection [1] because loop module is calling sysfs_remove_group()
when sysfs_create_group() failed.
Fix this by remembering whether sysfs_create_group() succeeded.

[1] https://syzkaller.appspot.com/bug?id=3f86c0edf75c86d2633aeb9dd69eccc70bc7e90b

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+9f03168400f56df89dbc6f1751f4458fe739ff29@syzkaller.appspotmail.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Renamed sysfs_ready -> sysfs_inited.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
loop: add recursion validation to LOOP_CHANGE_FD 2018-07-17T09:39:32+00:00 Theodore Ts'o tytso@mit.edu 2018-05-07T15:37:58+00:00 6f9f5797fc7de2e9f801b2f7af0726e1349d33a4 commit d2ac838e4cd7e5e9891ecc094d626734b0245c99 upstream. Refactor the validation code used in LOOP_SET_FD so it is also used in LOOP_CHANGE_FD. Otherwise it is possible to construct a set of loop devices that all refer to each other. This can lead to a infinite loop in starting with "while (is_loop_device(f)) .." in loop_set_fd(). Fix this by refactoring out the validation code and using it for LOOP_CHANGE_FD as well as LOOP_SET_FD. Reported-by: syzbot+4349872271ece473a7c91190b68b4bac7c5dbc87@syzkaller.appspotmail.com Reported-by: syzbot+40bd32c4d9a3cc12a339@syzkaller.appspotmail.com Reported-by: syzbot+769c54e66f994b041be7@syzkaller.appspotmail.com Reported-by: syzbot+0a89a9ce473936c57065@syzkaller.appspotmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit d2ac838e4cd7e5e9891ecc094d626734b0245c99 upstream.

Refactor the validation code used in LOOP_SET_FD so it is also used in
LOOP_CHANGE_FD.  Otherwise it is possible to construct a set of loop
devices that all refer to each other.  This can lead to a infinite
loop in starting with "while (is_loop_device(f)) .." in loop_set_fd().

Fix this by refactoring out the validation code and using it for
LOOP_CHANGE_FD as well as LOOP_SET_FD.

Reported-by: syzbot+4349872271ece473a7c91190b68b4bac7c5dbc87@syzkaller.appspotmail.com
Reported-by: syzbot+40bd32c4d9a3cc12a339@syzkaller.appspotmail.com
Reported-by: syzbot+769c54e66f994b041be7@syzkaller.appspotmail.com
Reported-by: syzbot+0a89a9ce473936c57065@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drbd: fix access after free 2018-07-11T14:29:14+00:00 Lars Ellenberg lars.ellenberg@linbit.com 2018-06-25T09:39:52+00:00 0ce6c46463715cecf78e6b92381f05dd47724f65 commit 64dafbc9530c10300acffc57fae3269d95fa8f93 upstream. We have struct drbd_requests { ... struct bio *private_bio; ... } to hold a bio clone for local submission. On local IO completion, we put that bio, and in case we want to use the result later, we overload that member to hold the ERR_PTR() of the completion result, Which, before v4.3, used to be the passed in "int error", so we could first bio_put(), then assign. v4.3-rc1~100^2~21 4246a0b63bd8 block: add a bi_error field to struct bio changed that: bio_put(req->private_bio); - req->private_bio = ERR_PTR(error); + req->private_bio = ERR_PTR(bio->bi_error); Which introduces an access after free, because it was non obvious that req->private_bio == bio. Impact of that was mostly unnoticable, because we only use that value in a multiple-failure case, and even then map any "unexpected" error code to EIO, so worst case we could potentially mask a more specific error with EIO in a multiple failure case. Unless the pointed to memory region was unmapped, as is the case with CONFIG_DEBUG_PAGEALLOC, in which case this results in BUG: unable to handle kernel paging request v4.13-rc1~70^2~75 4e4cbee93d56 block: switch bios to blk_status_t changes it further to bio_put(req->private_bio); req->private_bio = ERR_PTR(blk_status_to_errno(bio->bi_status)); And blk_status_to_errno() now contains a WARN_ON_ONCE() for unexpected values, which catches this "sometimes", if the memory has been reused quickly enough for other things. Should also go into stable since 4.3, with the trivial change around 4.13. Cc: stable@vger.kernel.org Fixes: 4246a0b63bd8 block: add a bi_error field to struct bio Reported-by: Sarah Newman <srn@prgmr.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 64dafbc9530c10300acffc57fae3269d95fa8f93 upstream.

We have
  struct drbd_requests { ... struct bio *private_bio;  ... }
to hold a bio clone for local submission.

On local IO completion, we put that bio, and in case we want to use the
result later, we overload that member to hold the ERR_PTR() of the
completion result,

Which, before v4.3, used to be the passed in "int error",
so we could first bio_put(), then assign.

v4.3-rc1~100^2~21 4246a0b63bd8 block: add a bi_error field to struct bio
changed that:
  	bio_put(req->private_bio);
 -	req->private_bio = ERR_PTR(error);
 +	req->private_bio = ERR_PTR(bio->bi_error);

Which introduces an access after free,
because it was non obvious that req->private_bio == bio.

Impact of that was mostly unnoticable, because we only use that value
in a multiple-failure case, and even then map any "unexpected" error
code to EIO, so worst case we could potentially mask a more specific
error with EIO in a multiple failure case.

Unless the pointed to memory region was unmapped, as is the case with
CONFIG_DEBUG_PAGEALLOC, in which case this results in

  BUG: unable to handle kernel paging request

v4.13-rc1~70^2~75 4e4cbee93d56 block: switch bios to blk_status_t
changes it further to
  	bio_put(req->private_bio);
  	req->private_bio = ERR_PTR(blk_status_to_errno(bio->bi_status));

And blk_status_to_errno() now contains a WARN_ON_ONCE() for unexpected
values, which catches this "sometimes", if the memory has been reused
quickly enough for other things.

Should also go into stable since 4.3, with the trivial change around 4.13.

Cc: stable@vger.kernel.org
Fixes: 4246a0b63bd8 block: add a bi_error field to struct bio
Reported-by: Sarah Newman <srn@prgmr.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rbd: flush rbd_dev->watch_dwork after watch is unregistered 2018-07-03T09:25:03+00:00 Dongsheng Yang dongsheng.yang@easystack.cn 2018-06-04T10:24:37+00:00 76022230aa643deebdc4e4c551f3da7782bb3dee commit 23edca864951250af845a11da86bb3ea63522ed2 upstream. There is a problem if we are going to unmap a rbd device and the watch_dwork is going to queue delayed work for watch: unmap Thread watch Thread timer do_rbd_remove cancel_tasks_sync(rbd_dev) queue_delayed_work for watch destroy_workqueue(rbd_dev->task_wq) drain_workqueue(wq) destroy other resources in wq call_timer_fn __queue_work() Then the delayed work escape the cancel_tasks_sync() and destroy_workqueue() and we will get an user-after-free call trace: BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI Modules linked in: CPU: 7 PID: 0 Comm: swapper/7 Tainted: G OE 4.17.0-rc6+ #13 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 RIP: 0010:__queue_work+0x6a/0x3b0 RSP: 0018:ffff9427df1c3e90 EFLAGS: 00010086 RAX: ffff9427deca8400 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff9427deca8400 RSI: ffff9427df1c3e50 RDI: 0000000000000000 RBP: ffff942783e39e00 R08: ffff9427deca8400 R09: ffff9427df1c3f00 R10: 0000000000000004 R11: 0000000000000005 R12: ffff9427cfb85970 R13: 0000000000002000 R14: 000000000001eca0 R15: 0000000000000007 FS: 0000000000000000(0000) GS:ffff9427df1c0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000004c900a005 CR4: 00000000000206e0 Call Trace: <IRQ> ? __queue_work+0x3b0/0x3b0 call_timer_fn+0x2d/0x130 run_timer_softirq+0x16e/0x430 ? tick_sched_timer+0x37/0x70 __do_softirq+0xd2/0x280 irq_exit+0xd5/0xe0 smp_apic_timer_interrupt+0x6c/0x130 apic_timer_interrupt+0xf/0x20 [ Move rbd_dev->watch_dwork cancellation so that rbd_reregister_watch() either bails out early because the watch is UNREGISTERED at that point or just gets cancelled. ] Cc: stable@vger.kernel.org Fixes: 99d1694310df ("rbd: retry watch re-registration periodically") Signed-off-by: Dongsheng Yang <dongsheng.yang@easystack.cn> Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 23edca864951250af845a11da86bb3ea63522ed2 upstream.

There is a problem if we are going to unmap a rbd device and the
watch_dwork is going to queue delayed work for watch:

unmap Thread                    watch Thread                  timer
do_rbd_remove
  cancel_tasks_sync(rbd_dev)
                                queue_delayed_work for watch
  destroy_workqueue(rbd_dev->task_wq)
    drain_workqueue(wq)
    destroy other resources in wq
                                                              call_timer_fn
                                                                __queue_work()

Then the delayed work escape the cancel_tasks_sync() and
destroy_workqueue() and we will get an user-after-free call trace:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
  PGD 0 P4D 0
  Oops: 0000 [#1] SMP PTI
  Modules linked in:
  CPU: 7 PID: 0 Comm: swapper/7 Tainted: G           OE     4.17.0-rc6+ #13
  Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
  RIP: 0010:__queue_work+0x6a/0x3b0
  RSP: 0018:ffff9427df1c3e90 EFLAGS: 00010086
  RAX: ffff9427deca8400 RBX: 0000000000000000 RCX: 0000000000000000
  RDX: ffff9427deca8400 RSI: ffff9427df1c3e50 RDI: 0000000000000000
  RBP: ffff942783e39e00 R08: ffff9427deca8400 R09: ffff9427df1c3f00
  R10: 0000000000000004 R11: 0000000000000005 R12: ffff9427cfb85970
  R13: 0000000000002000 R14: 000000000001eca0 R15: 0000000000000007
  FS:  0000000000000000(0000) GS:ffff9427df1c0000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000000000 CR3: 00000004c900a005 CR4: 00000000000206e0
  Call Trace:
   <IRQ>
   ? __queue_work+0x3b0/0x3b0
   call_timer_fn+0x2d/0x130
   run_timer_softirq+0x16e/0x430
   ? tick_sched_timer+0x37/0x70
   __do_softirq+0xd2/0x280
   irq_exit+0xd5/0xe0
   smp_apic_timer_interrupt+0x6c/0x130
   apic_timer_interrupt+0xf/0x20

[ Move rbd_dev->watch_dwork cancellation so that rbd_reregister_watch()
  either bails out early because the watch is UNREGISTERED at that point
  or just gets cancelled. ]

Cc: stable@vger.kernel.org
Fixes: 99d1694310df ("rbd: retry watch re-registration periodically")
Signed-off-by: Dongsheng Yang <dongsheng.yang@easystack.cn>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nbd: use bd_set_size when updating disk size 2018-06-26T00:06:32+00:00 Josef Bacik jbacik@fb.com 2018-05-16T18:51:19+00:00 00946218ffe376ff3234ff3c81cd4193e3ca95e2 commit 9e2b19675d1338d2a38e99194756f2db44a081df upstream. When we stopped relying on the bdev everywhere I broke updating the block device size on the fly, which ceph relies on. We can't just do set_capacity, we also have to do bd_set_size so things like parted will notice the device size change. Fixes: 29eaadc ("nbd: stop using the bdev everywhere") cc: stable@vger.kernel.org Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 9e2b19675d1338d2a38e99194756f2db44a081df upstream.

When we stopped relying on the bdev everywhere I broke updating the
block device size on the fly, which ceph relies on.  We can't just do
set_capacity, we also have to do bd_set_size so things like parted will
notice the device size change.

Fixes: 29eaadc ("nbd: stop using the bdev everywhere")
cc: stable@vger.kernel.org
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nbd: update size when connected 2018-06-26T00:06:31+00:00 Josef Bacik jbacik@fb.com 2018-05-16T18:51:18+00:00 a477d00557f59a20de6398a20808998ce97dce08 commit c3f7c9397609705ef848cc98a5fb429b3e90c3c4 upstream. I messed up changing the size of an NBD device while it was connected by not actually updating the device or doing the uevent. Fix this by updating everything if we're connected and we change the size. cc: stable@vger.kernel.org Fixes: 639812a ("nbd: don't set the device size until we're connected") Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c3f7c9397609705ef848cc98a5fb429b3e90c3c4 upstream.

I messed up changing the size of an NBD device while it was connected by
not actually updating the device or doing the uevent.  Fix this by
updating everything if we're connected and we change the size.

cc: stable@vger.kernel.org
Fixes: 639812a ("nbd: don't set the device size until we're connected")
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nbd: fix nbd device deletion 2018-06-26T00:06:31+00:00 Josef Bacik jbacik@fb.com 2018-05-16T18:51:17+00:00 edee2e826640c1ba54d51914b1699bc24a1f32c9 commit 8364da4751cf22201d74933d5e634176f44ed407 upstream. This fixes a use after free bug, we shouldn't be doing disk->queue right after we do del_gendisk(disk). Save the queue and do the cleanup after the del_gendisk. Fixes: c6a4759ea0c9 ("nbd: add device refcounting") cc: stable@vger.kernel.org Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8364da4751cf22201d74933d5e634176f44ed407 upstream.

This fixes a use after free bug, we shouldn't be doing disk->queue right
after we do del_gendisk(disk).  Save the queue and do the cleanup after
the del_gendisk.

Fixes: c6a4759ea0c9 ("nbd: add device refcounting")
cc: stable@vger.kernel.org
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
block: null_blk: fix 'Invalid parameters' when loading module 2018-05-30T05:52:36+00:00 Ming Lei ming.lei@redhat.com 2018-03-06T04:07:13+00:00 a64948842d00b72ee19854ff96dfb77e6aad4c34 [ Upstream commit 66231ad3e2886ba99fbf440cea44cab547e5163f ] On ARM64, the default page size has been 64K on some distributions, and we should allow ARM64 people to play null_blk. This patch fixes the issue by extend page bitmap size for supporting other non-4KB PAGE_SIZE. Cc: Bart Van Assche <Bart.VanAssche@wdc.com> Cc: Shaohua Li <shli@kernel.org> Cc: Kyungchan Koh <kkc6196@fb.com>, Cc: weiping zhang <zhangweiping@didichuxing.com> Cc: Yi Zhang <yi.zhang@redhat.com> Reported-by: Yi Zhang <yi.zhang@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 66231ad3e2886ba99fbf440cea44cab547e5163f ]

On ARM64, the default page size has been 64K on some distributions, and
we should allow ARM64 people to play null_blk.

This patch fixes the issue by extend page bitmap size for supporting
other non-4KB PAGE_SIZE.

Cc: Bart Van Assche <Bart.VanAssche@wdc.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Kyungchan Koh <kkc6196@fb.com>,
Cc: weiping zhang <zhangweiping@didichuxing.com>
Cc: Yi Zhang <yi.zhang@redhat.com>
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cdrom: do not call check_disk_change() inside cdrom_open() 2018-05-30T05:52:34+00:00 Maurizio Lombardi mlombard@redhat.com 2018-03-09T12:59:06+00:00 e6e5de32470b8498221640d448ae316560b43a34 [ Upstream commit 2bbea6e117357d17842114c65e9a9cf2d13ae8a3 ] when mounting an ISO filesystem sometimes (very rarely) the system hangs because of a race condition between two tasks. PID: 6766 TASK: ffff88007b2a6dd0 CPU: 0 COMMAND: "mount" #0 [ffff880078447ae0] __schedule at ffffffff8168d605 #1 [ffff880078447b48] schedule_preempt_disabled at ffffffff8168ed49 #2 [ffff880078447b58] __mutex_lock_slowpath at ffffffff8168c995 #3 [ffff880078447bb8] mutex_lock at ffffffff8168bdef #4 [ffff880078447bd0] sr_block_ioctl at ffffffffa00b6818 [sr_mod] #5 [ffff880078447c10] blkdev_ioctl at ffffffff812fea50 #6 [ffff880078447c70] ioctl_by_bdev at ffffffff8123a8b3 #7 [ffff880078447c90] isofs_fill_super at ffffffffa04fb1e1 [isofs] #8 [ffff880078447da8] mount_bdev at ffffffff81202570 #9 [ffff880078447e18] isofs_mount at ffffffffa04f9828 [isofs] #10 [ffff880078447e28] mount_fs at ffffffff81202d09 #11 [ffff880078447e70] vfs_kern_mount at ffffffff8121ea8f #12 [ffff880078447ea8] do_mount at ffffffff81220fee #13 [ffff880078447f28] sys_mount at ffffffff812218d6 #14 [ffff880078447f80] system_call_fastpath at ffffffff81698c49 RIP: 00007fd9ea914e9a RSP: 00007ffd5d9bf648 RFLAGS: 00010246 RAX: 00000000000000a5 RBX: ffffffff81698c49 RCX: 0000000000000010 RDX: 00007fd9ec2bc210 RSI: 00007fd9ec2bc290 RDI: 00007fd9ec2bcf30 RBP: 0000000000000000 R8: 0000000000000000 R9: 0000000000000010 R10: 00000000c0ed0001 R11: 0000000000000206 R12: 00007fd9ec2bc040 R13: 00007fd9eb6b2380 R14: 00007fd9ec2bc210 R15: 00007fd9ec2bcf30 ORIG_RAX: 00000000000000a5 CS: 0033 SS: 002b This task was trying to mount the cdrom. It allocated and configured a super_block struct and owned the write-lock for the super_block->s_umount rwsem. While exclusively owning the s_umount lock, it called sr_block_ioctl and waited to acquire the global sr_mutex lock. PID: 6785 TASK: ffff880078720fb0 CPU: 0 COMMAND: "systemd-udevd" #0 [ffff880078417898] __schedule at ffffffff8168d605 #1 [ffff880078417900] schedule at ffffffff8168dc59 #2 [ffff880078417910] rwsem_down_read_failed at ffffffff8168f605 #3 [ffff880078417980] call_rwsem_down_read_failed at ffffffff81328838 #4 [ffff8800784179d0] down_read at ffffffff8168cde0 #5 [ffff8800784179e8] get_super at ffffffff81201cc7 #6 [ffff880078417a10] __invalidate_device at ffffffff8123a8de #7 [ffff880078417a40] flush_disk at ffffffff8123a94b #8 [ffff880078417a88] check_disk_change at ffffffff8123ab50 #9 [ffff880078417ab0] cdrom_open at ffffffffa00a29e1 [cdrom] #10 [ffff880078417b68] sr_block_open at ffffffffa00b6f9b [sr_mod] #11 [ffff880078417b98] __blkdev_get at ffffffff8123ba86 #12 [ffff880078417bf0] blkdev_get at ffffffff8123bd65 #13 [ffff880078417c78] blkdev_open at ffffffff8123bf9b #14 [ffff880078417c90] do_dentry_open at ffffffff811fc7f7 #15 [ffff880078417cd8] vfs_open at ffffffff811fc9cf #16 [ffff880078417d00] do_last at ffffffff8120d53d #17 [ffff880078417db0] path_openat at ffffffff8120e6b2 #18 [ffff880078417e48] do_filp_open at ffffffff8121082b #19 [ffff880078417f18] do_sys_open at ffffffff811fdd33 #20 [ffff880078417f70] sys_open at ffffffff811fde4e #21 [ffff880078417f80] system_call_fastpath at ffffffff81698c49 RIP: 00007f29438b0c20 RSP: 00007ffc76624b78 RFLAGS: 00010246 RAX: 0000000000000002 RBX: ffffffff81698c49 RCX: 0000000000000000 RDX: 00007f2944a5fa70 RSI: 00000000000a0800 RDI: 00007f2944a5fa70 RBP: 00007f2944a5f540 R8: 0000000000000000 R9: 0000000000000020 R10: 00007f2943614c40 R11: 0000000000000246 R12: ffffffff811fde4e R13: ffff880078417f78 R14: 000000000000000c R15: 00007f2944a4b010 ORIG_RAX: 0000000000000002 CS: 0033 SS: 002b This task tried to open the cdrom device, the sr_block_open function acquired the global sr_mutex lock. The call to check_disk_change() then saw an event flag indicating a possible media change and tried to flush any cached data for the device. As part of the flush, it tried to acquire the super_block->s_umount lock associated with the cdrom device. This was the same super_block as created and locked by the previous task. The first task acquires the s_umount lock and then the sr_mutex_lock; the second task acquires the sr_mutex_lock and then the s_umount lock. This patch fixes the issue by moving check_disk_change() out of cdrom_open() and let the caller take care of it. Signed-off-by: Maurizio Lombardi <mlombard@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 2bbea6e117357d17842114c65e9a9cf2d13ae8a3 ]

when mounting an ISO filesystem sometimes (very rarely)
the system hangs because of a race condition between two tasks.

PID: 6766   TASK: ffff88007b2a6dd0  CPU: 0   COMMAND: "mount"
 #0 [ffff880078447ae0] __schedule at ffffffff8168d605
 #1 [ffff880078447b48] schedule_preempt_disabled at ffffffff8168ed49
 #2 [ffff880078447b58] __mutex_lock_slowpath at ffffffff8168c995
 #3 [ffff880078447bb8] mutex_lock at ffffffff8168bdef
 #4 [ffff880078447bd0] sr_block_ioctl at ffffffffa00b6818 [sr_mod]
 #5 [ffff880078447c10] blkdev_ioctl at ffffffff812fea50
 #6 [ffff880078447c70] ioctl_by_bdev at ffffffff8123a8b3
 #7 [ffff880078447c90] isofs_fill_super at ffffffffa04fb1e1 [isofs]
 #8 [ffff880078447da8] mount_bdev at ffffffff81202570
 #9 [ffff880078447e18] isofs_mount at ffffffffa04f9828 [isofs]
#10 [ffff880078447e28] mount_fs at ffffffff81202d09
#11 [ffff880078447e70] vfs_kern_mount at ffffffff8121ea8f
#12 [ffff880078447ea8] do_mount at ffffffff81220fee
#13 [ffff880078447f28] sys_mount at ffffffff812218d6
#14 [ffff880078447f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007fd9ea914e9a  RSP: 00007ffd5d9bf648  RFLAGS: 00010246
    RAX: 00000000000000a5  RBX: ffffffff81698c49  RCX: 0000000000000010
    RDX: 00007fd9ec2bc210  RSI: 00007fd9ec2bc290  RDI: 00007fd9ec2bcf30
    RBP: 0000000000000000   R8: 0000000000000000   R9: 0000000000000010
    R10: 00000000c0ed0001  R11: 0000000000000206  R12: 00007fd9ec2bc040
    R13: 00007fd9eb6b2380  R14: 00007fd9ec2bc210  R15: 00007fd9ec2bcf30
    ORIG_RAX: 00000000000000a5  CS: 0033  SS: 002b

This task was trying to mount the cdrom.  It allocated and configured a
super_block struct and owned the write-lock for the super_block->s_umount
rwsem. While exclusively owning the s_umount lock, it called
sr_block_ioctl and waited to acquire the global sr_mutex lock.

PID: 6785   TASK: ffff880078720fb0  CPU: 0   COMMAND: "systemd-udevd"
 #0 [ffff880078417898] __schedule at ffffffff8168d605
 #1 [ffff880078417900] schedule at ffffffff8168dc59
 #2 [ffff880078417910] rwsem_down_read_failed at ffffffff8168f605
 #3 [ffff880078417980] call_rwsem_down_read_failed at ffffffff81328838
 #4 [ffff8800784179d0] down_read at ffffffff8168cde0
 #5 [ffff8800784179e8] get_super at ffffffff81201cc7
 #6 [ffff880078417a10] __invalidate_device at ffffffff8123a8de
 #7 [ffff880078417a40] flush_disk at ffffffff8123a94b
 #8 [ffff880078417a88] check_disk_change at ffffffff8123ab50
 #9 [ffff880078417ab0] cdrom_open at ffffffffa00a29e1 [cdrom]
#10 [ffff880078417b68] sr_block_open at ffffffffa00b6f9b [sr_mod]
#11 [ffff880078417b98] __blkdev_get at ffffffff8123ba86
#12 [ffff880078417bf0] blkdev_get at ffffffff8123bd65
#13 [ffff880078417c78] blkdev_open at ffffffff8123bf9b
#14 [ffff880078417c90] do_dentry_open at ffffffff811fc7f7
#15 [ffff880078417cd8] vfs_open at ffffffff811fc9cf
#16 [ffff880078417d00] do_last at ffffffff8120d53d
#17 [ffff880078417db0] path_openat at ffffffff8120e6b2
#18 [ffff880078417e48] do_filp_open at ffffffff8121082b
#19 [ffff880078417f18] do_sys_open at ffffffff811fdd33
#20 [ffff880078417f70] sys_open at ffffffff811fde4e
#21 [ffff880078417f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007f29438b0c20  RSP: 00007ffc76624b78  RFLAGS: 00010246
    RAX: 0000000000000002  RBX: ffffffff81698c49  RCX: 0000000000000000
    RDX: 00007f2944a5fa70  RSI: 00000000000a0800  RDI: 00007f2944a5fa70
    RBP: 00007f2944a5f540   R8: 0000000000000000   R9: 0000000000000020
    R10: 00007f2943614c40  R11: 0000000000000246  R12: ffffffff811fde4e
    R13: ffff880078417f78  R14: 000000000000000c  R15: 00007f2944a4b010
    ORIG_RAX: 0000000000000002  CS: 0033  SS: 002b

This task tried to open the cdrom device, the sr_block_open function
acquired the global sr_mutex lock. The call to check_disk_change()
then saw an event flag indicating a possible media change and tried
to flush any cached data for the device.
As part of the flush, it tried to acquire the super_block->s_umount
lock associated with the cdrom device.
This was the same super_block as created and locked by the previous task.

The first task acquires the s_umount lock and then the sr_mutex_lock;
the second task acquires the sr_mutex_lock and then the s_umount lock.

This patch fixes the issue by moving check_disk_change() out of
cdrom_open() and let the caller take care of it.

Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
xen-blkfront: move negotiate_mq to cover all cases of new VBDs 2018-05-30T05:52:13+00:00 Bhavesh Davda bhavesh.davda@oracle.com 2017-12-22T22:17:13+00:00 9238d1fa3ee60e26909b5ca38e4fbfcd1dbc2201 [ Upstream commit 7ed8ce1c5fc7cf25b3602c73bef897a3466a6645 ] negotiate_mq should happen in all cases of a new VBD being discovered by xen-blkfront, whether called through _probe() or a hot-attached new VBD from dom-0 via xenstore. Otherwise, hot-attached new VBDs are left configured without multi-queue. Signed-off-by: Bhavesh Davda <bhavesh.davda@oracle.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 7ed8ce1c5fc7cf25b3602c73bef897a3466a6645 ]

negotiate_mq should happen in all cases of a new VBD being discovered by
xen-blkfront, whether called through _probe() or a hot-attached new VBD
from dom-0 via xenstore. Otherwise, hot-attached new VBDs are left
configured without multi-queue.

Signed-off-by: Bhavesh Davda <bhavesh.davda@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>