a856531951
xen_qlock_wait() isn't safe for nested calls due to interrupts. A call
of xen_qlock_kick() might be ignored in case a deeper nesting level
was active right before the call of xen_poll_irq():
CPU 1: CPU 2:
spin_lock(lock1)
spin_lock(lock1)
-> xen_qlock_wait()
-> xen_clear_irq_pending()
Interrupt happens
spin_unlock(lock1)
-> xen_qlock_kick(CPU 2)
spin_lock_irqsave(lock2)
spin_lock_irqsave(lock2)
-> xen_qlock_wait()
-> xen_clear_irq_pending()
clears kick for lock1
-> xen_poll_irq()
spin_unlock_irq_restore(lock2)
-> xen_qlock_kick(CPU 2)
wakes up
spin_unlock_irq_restore(lock2)
IRET
resumes in xen_qlock_wait()
-> xen_poll_irq()
never wakes up
The solution is to disable interrupts in xen_qlock_wait() and not to
poll for the irq in case xen_qlock_wait() is called in nmi context.
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>
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.