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authorThomas Gleixner <tglx@linutronix.de>2020-02-19 18:30:26 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-02-28 15:39:18 +0100
commit5d9635bc726921c1164c22e8519ac77fba3f0ce6 (patch)
tree61840a6bdfba80b1219533e91b3f18e685383a78
parent2245b29f02e971fa02fa270d5116b6f33dcfff13 (diff)
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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>
-rw-r--r--drivers/xen/preempt.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/xen/preempt.c b/drivers/xen/preempt.c
index 08cb419eb4e6..5f6b77ea34fb 100644
--- a/drivers/xen/preempt.c
+++ b/drivers/xen/preempt.c
@@ -37,7 +37,9 @@ asmlinkage __visible void xen_maybe_preempt_hcall(void)
* cpu.
*/
__this_cpu_write(xen_in_preemptible_hcall, false);
- _cond_resched();
+ local_irq_enable();
+ cond_resched();
+ local_irq_disable();
__this_cpu_write(xen_in_preemptible_hcall, true);
}
}