From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Thu, 27 Feb 2020 13:03:44 +0000 (+0100)
Subject: 4.4-stable patches
X-Git-Tag: v4.4.215~14
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d8b084366aae2b3eb36bb336f0086ab77a4a1874;p=thirdparty%2Fkernel%2Fstable-queue.git

4.4-stable patches

added patches:
	xen-enable-interrupts-when-calling-_cond_resched.patch
---

diff --git a/queue-4.4/series b/queue-4.4/series
index 25f4bba7c6c..1be0be8ed76 100644
--- a/queue-4.4/series
+++ b/queue-4.4/series
@@ -110,3 +110,4 @@ ecryptfs-replace-bug_on-with-error-handling-code.patch
 alsa-rawmidi-avoid-bit-fields-for-state-flags.patch
 alsa-seq-avoid-concurrent-access-to-queue-flags.patch
 alsa-seq-fix-concurrent-access-to-queue-current-tick-time.patch
+xen-enable-interrupts-when-calling-_cond_resched.patch
diff --git a/queue-4.4/xen-enable-interrupts-when-calling-_cond_resched.patch b/queue-4.4/xen-enable-interrupts-when-calling-_cond_resched.patch
new file mode 100644
index 00000000000..7499235f5ef
--- /dev/null
+++ b/queue-4.4/xen-enable-interrupts-when-calling-_cond_resched.patch
@@ -0,0 +1,43 @@
+From 8645e56a4ad6dcbf504872db7f14a2f67db88ef2 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Wed, 19 Feb 2020 18:30:26 +0100
+Subject: xen: Enable interrupts when calling _cond_resched()
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+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 |    4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+--- a/drivers/xen/preempt.c
++++ b/drivers/xen/preempt.c
+@@ -37,7 +37,9 @@ asmlinkage __visible void xen_maybe_pree
+ 		 * 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);
+ 	}
+ }