Farhan Ali cea5dde42a vfio-ccw: Do not call flush_workqueue while holding the spinlock
Currently we call flush_workqueue while holding the subchannel
spinlock. But flush_workqueue function can go to sleep, so
do not call the function while holding the spinlock.

Fixes the following bug:

[  285.203430] BUG: scheduling while atomic: bash/14193/0x00000002
[  285.203434] INFO: lockdep is turned off.
....
[  285.203485] Preemption disabled at:
[  285.203488] [<000003ff80243e5c>] vfio_ccw_sch_quiesce+0xbc/0x120 [vfio_ccw]
[  285.203496] CPU: 7 PID: 14193 Comm: bash Tainted: G        W
....
[  285.203504] Call Trace:
[  285.203510] ([<0000000000113772>] show_stack+0x82/0xd0)
[  285.203514]  [<0000000000b7a102>] dump_stack+0x92/0xd0
[  285.203518]  [<000000000017b8be>] __schedule_bug+0xde/0xf8
[  285.203524]  [<0000000000b95b5a>] __schedule+0x7a/0xc38
[  285.203528]  [<0000000000b9678a>] schedule+0x72/0xb0
[  285.203533]  [<0000000000b9bfbc>] schedule_timeout+0x34/0x528
[  285.203538]  [<0000000000b97608>] wait_for_common+0x118/0x1b0
[  285.203544]  [<0000000000166d6a>] flush_workqueue+0x182/0x548
[  285.203550]  [<000003ff80243e6e>] vfio_ccw_sch_quiesce+0xce/0x120 [vfio_ccw]
[  285.203556]  [<000003ff80245278>] vfio_ccw_mdev_reset+0x38/0x70 [vfio_ccw]
[  285.203562]  [<000003ff802458b0>] vfio_ccw_mdev_remove+0x40/0x78 [vfio_ccw]
[  285.203567]  [<000003ff801a499c>] mdev_device_remove_ops+0x3c/0x80 [mdev]
[  285.203573]  [<000003ff801a4d5c>] mdev_device_remove+0xc4/0x130 [mdev]
[  285.203578]  [<000003ff801a5074>] remove_store+0x6c/0xa8 [mdev]
[  285.203582]  [<000000000046f494>] kernfs_fop_write+0x14c/0x1f8
[  285.203588]  [<00000000003c1530>] __vfs_write+0x38/0x1a8
[  285.203593]  [<00000000003c187c>] vfs_write+0xb4/0x198
[  285.203597]  [<00000000003c1af2>] ksys_write+0x5a/0xb0
[  285.203601]  [<0000000000b9e270>] system_call+0xdc/0x2d8

Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Message-Id: <626bab8bb2958ae132452e1ddaf1b20882ad5a9d.1554756534.git.alifm@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
2019-04-24 14:18:51 +02:00
2019-03-07 18:32:03 -08:00
2019-03-28 08:54:20 -07:00
2019-03-28 08:54:20 -07:00
2019-04-10 17:48:34 +02:00
2019-02-21 11:41:19 +00:00
2019-03-24 14:02:26 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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