[PATCH 5.13 005/351] KVM: selftests: do not require 64GB in set_memory_region_test

[Greg Kroah-Hartman]

From: Christian Borntraeger <borntraeger@xxxxxxxxxx>

commit cd4220d23bf3f43cf720e82bdee681f383433ae2 upstream.

Unless the user sets overcommit_memory or has plenty of swap, the latest
changes to the testcase will result in ENOMEM failures for hosts with
less than 64GB RAM. As we do not use much of the allocated memory, we
can use MAP_NORESERVE to avoid this error.

Cc: Zenghui Yu <yuzenghui@xxxxxxxxxx>
Cc: vkuznets@xxxxxxxxxx
Cc: wanghaibin.wang@xxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 309505dd5685 ("KVM: selftests: Fix mapping length truncation in m{,un}map()")
Tested-by: Zenghui Yu <yuzenghui@xxxxxxxxxx>
Link: https://lore.kernel.org/kvm/20210701160425.33666-1-borntraeger@xxxxxxxxxx/
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 tools/testing/selftests/kvm/set_memory_region_test.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/set_memory_region_test.c b/tools/testing/selftests/kvm/set_memory_region_test.c
index d8812f27648c..d31f54ac4e98 100644
--- a/tools/testing/selftests/kvm/set_memory_region_test.c
+++ b/tools/testing/selftests/kvm/set_memory_region_test.c
@@ -377,7 +377,8 @@ static void test_add_max_memory_regions(void)
 		(max_mem_slots - 1), MEM_REGION_SIZE >> 10);
 
 	mem = mmap(NULL, (size_t)max_mem_slots * MEM_REGION_SIZE + alignment,
-		   PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+		   PROT_READ | PROT_WRITE,
+		   MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
 	TEST_ASSERT(mem != MAP_FAILED, "Failed to mmap() host");
 	mem_aligned = (void *)(((size_t) mem + alignment - 1) & ~(alignment - 1));
 
-- 
2.32.0