4.9-stable patches

added patches:
	xen-let-alloc_xenballooned_pages-fail-if-not-enough-memory-free.patch

diff --git a/queue-4.9/series b/queue-4.9/series
index 3ae21c91c337bd905910361dd1561dee33a2b4ab..4ece05b0add82d86cb0283fb316532e83639540c 100644 (file)
--- a/queue-4.9/series
+++ b/queue-4.9/series
@@ -74,3 +74,4 @@ gtp-fix-illegal-context-switch-in-rcu-read-side-crit.patch
 gtp-fix-use-after-free-in-gtp_newlink.patch
 floppy-fix-div-by-zero-in-setup_format_params.patch
 floppy-fix-out-of-bounds-read-in-copy_buffer.patch
+xen-let-alloc_xenballooned_pages-fail-if-not-enough-memory-free.patch

diff --git a/queue-4.9/xen-let-alloc_xenballooned_pages-fail-if-not-enough-memory-free.patch b/queue-4.9/xen-let-alloc_xenballooned_pages-fail-if-not-enough-memory-free.patch
new file mode 100644 (file)
index 0000000..02b06cf
--- /dev/null
+++ b/queue-4.9/xen-let-alloc_xenballooned_pages-fail-if-not-enough-memory-free.patch
@@ -0,0 +1,70 @@
+From a1078e821b605813b63bf6bca414a85f804d5c66 Mon Sep 17 00:00:00 2001
+From: Juergen Gross <jgross@suse.com>
+Date: Wed, 19 Jun 2019 11:00:56 +0200
+Subject: xen: let alloc_xenballooned_pages() fail if not enough memory free
+
+From: Juergen Gross <jgross@suse.com>
+
+commit a1078e821b605813b63bf6bca414a85f804d5c66 upstream.
+
+Instead of trying to allocate pages with GFP_USER in
+add_ballooned_pages() check the available free memory via
+si_mem_available(). GFP_USER is far less limiting memory exhaustion
+than the test via si_mem_available().
+
+This will avoid dom0 running out of memory due to excessive foreign
+page mappings especially on ARM and on x86 in PVH mode, as those don't
+have a pre-ballooned area which can be used for foreign mappings.
+
+As the normal ballooning suffers from the same problem don't balloon
+down more than si_mem_available() pages in one iteration. At the same
+time limit the default maximum number of retries.
+
+This is part of XSA-300.
+
+Signed-off-by: Juergen Gross <jgross@suse.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/xen/balloon.c |   16 +++++++++++++---
+ 1 file changed, 13 insertions(+), 3 deletions(-)
+
+--- a/drivers/xen/balloon.c
++++ b/drivers/xen/balloon.c
+@@ -591,8 +591,15 @@ static void balloon_process(struct work_
+                               state = reserve_additional_memory();
+               }
+ 
+-              if (credit < 0)
+-                      state = decrease_reservation(-credit, GFP_BALLOON);
++              if (credit < 0) {
++                      long n_pages;
++
++                      n_pages = min(-credit, si_mem_available());
++                      state = decrease_reservation(n_pages, GFP_BALLOON);
++                      if (state == BP_DONE && n_pages != -credit &&
++                          n_pages < totalreserve_pages)
++                              state = BP_EAGAIN;
++              }
+ 
+               state = update_schedule(state);
+ 
+@@ -631,6 +638,9 @@ static int add_ballooned_pages(int nr_pa
+               }
+       }
+ 
++      if (si_mem_available() < nr_pages)
++              return -ENOMEM;
++
+       st = decrease_reservation(nr_pages, GFP_USER);
+       if (st != BP_DONE)
+               return -ENOMEM;
+@@ -754,7 +764,7 @@ static int __init balloon_init(void)
+       balloon_stats.schedule_delay = 1;
+       balloon_stats.max_schedule_delay = 32;
+       balloon_stats.retry_count = 1;
+-      balloon_stats.max_retry_count = RETRY_UNLIMITED;
++      balloon_stats.max_retry_count = 4;
+ 
+ #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+       set_online_page_callback(&xen_online_page);