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a856531951
linux/arch/x86/xen
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Juergen Gross a856531951 xen: make xen_qlock_wait() nestable 
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>
2018-10-24 10:18:04 +02:00
..
apic.c Merge branch 'WIP.x86/asm' into x86/urgent, because the topic is ready 2018-04-12 09:42:34 +02:00
debugfs.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
debugfs.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
efi.c x86/xen: Add SPDX identifier in arch/x86/xen files 2018-09-03 16:50:33 +02:00
enlighten_hvm.c x86/xen: Add SPDX identifier in arch/x86/xen files 2018-09-03 16:50:33 +02:00
enlighten_pv.c x86/paravirt: Use a single ops structure 2018-09-03 16:50:35 +02:00
enlighten_pvh.c Merge branch 'x86-grub2-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-23 16:31:33 +01:00
enlighten.c Merge branch 'x86-paravirt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-23 17:54:58 +01:00
grant-table.c x86/xen: Add SPDX identifier in arch/x86/xen files 2018-09-03 16:50:33 +02:00
irq.c x86/paravirt: Use a single ops structure 2018-09-03 16:50:35 +02:00
Kconfig Merge branch 'x86-paravirt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-23 17:54:58 +01:00
Makefile x86/xen: Link platform-pci-unplug.o only if CONFIG_XEN_PVHVM 2018-09-03 16:50:33 +02:00
mmu_hvm.c x86/paravirt: Use a single ops structure 2018-09-03 16:50:35 +02:00
mmu_pv.c Merge branch 'x86-paravirt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-23 17:54:58 +01:00
mmu.c x86/xen: Add SPDX identifier in arch/x86/xen files 2018-09-03 16:50:33 +02:00
mmu.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
multicalls.c xen: don't use privcmd_call() from xen_mc_flush() 2018-08-07 11:37:01 -04:00
multicalls.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
p2m.c x86/xen: Add SPDX identifier in arch/x86/xen files 2018-09-03 16:50:33 +02:00
pci-swiotlb-xen.c x86/xen: Add SPDX identifier in arch/x86/xen files 2018-09-03 16:50:33 +02:00
platform-pci-unplug.c Merge branch 'x86-paravirt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-23 17:54:58 +01:00
pmu.c Merge branch 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-23 16:16:40 +01:00
pmu.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
setup.c x86/xen: remove unused function xen_auto_xlated_memory_setup() 2018-08-20 14:46:18 -04:00
smp_hvm.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
smp_pv.c x86/stackprotector: Remove the call to boot_init_stack_canary() from cpu_startup_entry() 2018-10-22 04:07:24 +02:00
smp.c x86/xen: Calculate __max_logical_packages on PV domains 2018-02-17 09:40:45 +01:00
smp.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
spinlock.c xen: make xen_qlock_wait() nestable 2018-10-24 10:18:04 +02:00
suspend_hvm.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
suspend_pv.c x86/xen/time: Initialize pv xen time in init_hypervisor_platform() 2018-07-20 00:02:39 +02:00
suspend.c x86/xen: Zero MSR_IA32_SPEC_CTRL before suspend 2018-02-28 16:03:19 +01:00
time.c x86/paravirt: Use a single ops structure 2018-09-03 16:50:35 +02:00
trace.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vdso.h x86/xen: Add SPDX identifier in arch/x86/xen files 2018-09-03 16:50:33 +02:00
vga.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xen-asm_32.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xen-asm_64.S x86/entry/64: Use the TSS sp2 slot for SYSCALL/SYSRET scratch space 2018-09-08 11:20:11 +02:00
xen-asm.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xen-head.S xen/pvh: Indicate XENFEAT_linux_rsdp_unrestricted to Xen 2018-04-10 09:22:22 -04:00
xen-ops.h x86/xen: remove unused function xen_auto_xlated_memory_setup() 2018-08-20 14:46:18 -04:00
xen-pvh.S x86/xen: Add SPDX identifier in arch/x86/xen files 2018-09-03 16:50:33 +02:00