xen: Enable interrupts when calling _cond_resched()
authorThomas Gleixner <tglx@linutronix.de>
Wed, 19 Feb 2020 17:30:26 +0000 (18:30 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 28 Feb 2020 14:42:57 +0000 (15:42 +0100)
commit1d982f7f03d28dfdd6f9562d13c94ccbbb3b9e11
tree324ecdc58c36cad65d965b04c4d3ff3853851e05
parentdfbf24128630ed4f38f18f7ca12b58a7ba6964ad
xen: Enable interrupts when calling _cond_resched()

commit 8645e56a4ad6dcbf504872db7f14a2f67db88ef2 upstream.

xen_maybe_preempt_hcall() is called from the exception entry point
xen_do_hypervisor_callback with interrupts disabled.

_cond_resched() evades the might_sleep() check in cond_resched() which
would have caught that and schedule_debug() unfortunately lacks a check
for irqs_disabled().

Enable interrupts around the call and use cond_resched() to catch future
issues.

Fixes: fdfd811ddde3 ("x86/xen: allow privcmd hypercalls to be preempted")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/878skypjrh.fsf@nanos.tec.linutronix.de
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/xen/preempt.c