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Filename Latest commit message Latest commit date
Juergen Gross 2ac2a7d4d9 xen: fix race in xen_qlock_wait()
In the following situation a vcpu waiting for a lock might not be
woken up from xen_poll_irq():

CPU 1:                CPU 2:                      CPU 3:
takes a spinlock
                      tries to get lock
                      -> xen_qlock_wait()
frees the lock
-> xen_qlock_kick(cpu2)
                        -> xen_clear_irq_pending()

takes lock again
                                                  tries to get lock
                                                  -> *lock = _Q_SLOW_VAL
                        -> *lock == _Q_SLOW_VAL ?
                        -> xen_poll_irq()
frees the lock
-> xen_qlock_kick(cpu3)

And cpu 2 will sleep forever.

This can be avoided easily by modifying xen_qlock_wait() to call
xen_poll_irq() only if the related irq was not pending and to call
xen_clear_irq_pending() only if it was pending.

Cc: stable@vger.kernel.org
Cc: Waiman.Long@hp.com
Cc: peterz@infradead.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
2018-10-24 10:17:38 +02:00
arch xen: fix race in xen_qlock_wait() 2018-10-24 10:17:38 +02:00
block for-4.20/block-20181021 2018-10-22 17:46:08 +01:00
certs
crypto Revert "net: simplify sock_poll_wait" 2018-10-23 10:57:06 -07:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-10-24 06:47:44 +01:00
drivers xen/balloon: Grammar s/Is it/It is/ 2018-10-24 10:17:16 +02:00
firmware
fs Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-10-24 06:47:44 +01:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-10-24 06:47:44 +01:00
init Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-23 15:00:03 +01:00
ipc ipc/shm.c: use ERR_CAST() for shm_lock() error return 2018-10-05 16:32:04 -07:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-10-24 06:47:44 +01:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-10-24 06:47:44 +01:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-23 17:05:28 +01:00
net tcp: add tcp_reset_xmit_timer() helper 2018-10-23 19:42:44 -07:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-10-12 21:38:46 -07:00
scripts Merge branch 'parisc-4.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux 2018-10-23 20:02:03 +01:00
security
sound Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-23 13:32:18 +01:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-10-24 06:47:44 +01:00
usr
virt arm64 updates for 4.20: 2018-10-22 17:30:06 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-10-24 06:47:44 +01:00
Makefile Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-23 13:08:53 +01:00
README

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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.