This tests memory leak, by loading/unloading nullblk driver.
Steps:
1. Load nullblk driver with memory_backed=1
2. "dd" of 50M
3. Unload null-blk driver
We do it for 5 iterations to avoid any noise.
Commit 8cfb98196cceec35416041c6b91212d2b99392e4 fixes issue in kernel
Signed-off-by: Nitesh Shetty <nj.shetty@xxxxxxxxxxx>
---
tests/block/034 | 60 +++++++++++++++++++++++++++++++++++++++++++++
tests/block/034.out | 2 ++
2 files changed, 62 insertions(+)
create mode 100644 tests/block/034
create mode 100644 tests/block/034.out
diff --git a/tests/block/034 b/tests/block/034
new file mode 100644
index 0000000..9a3bec4
--- /dev/null
+++ b/tests/block/034
@@ -0,0 +1,60 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-3.0+
+# Copyright (C) 2023 Nitesh Shetty
+#
+# Check memory leak when null_blk driver is loaded with memory_backed=1
+
+. tests/block/rc
+. common/null_blk
+
+DESCRIPTION="load/unload null_blk memory_backed=1 to check memleak"
+QUICK=1
+
+requires() {
+ _have_module null_blk
+ _have_module_param null_blk memory_backed
+ _have_program dd
+}
+
+run_nullblk_dd() {
+ if ! _init_null_blk memory_backed=1; then
+ echo "Loading null_blk failed"
+ return 1
+ fi
+ dd if=/dev/urandom of=/dev/nullb0 oflag=direct bs=1M count="$1" > \
+ /dev/null 2>&1
+ _exit_null_blk
+}
+
+free_memory() {
+ sed -n -e 's/^MemFree:[[:blank:]]*\([0-9]*\)[[:blank:]]*kB$/\1/p' \
+ /proc/meminfo
+}
+
+test() {
+ echo "Running ${TEST_NAME}"
+
+ local mem_leak=0 size=50
+ local i mem_start mem_end mem_used
+
+ for ((i = 0; i < 5; i++)); do
+ mem_start=$(free_memory)
+ run_nullblk_dd $size
+ mem_end=$(free_memory)
+
+ mem_used=$(((mem_start - mem_end) / 1024))
+ # -10MB to account for some randomness in freeing by some
+ # simultaneous process
+ if ((mem_used >= size - 10)); then
+ mem_leak=$((mem_leak + 1))
+ fi
+ done
+
+ # There might be possibilty of some random process freeing up memory at
+ # same time nullblk is unloaded.
+ # we consider 3/5 times to be positive.
+ if ((mem_leak > 3)); then
+ echo "Memleak: Memory is not freed by null-blk driver"
+ fi
+ echo "Test complete"
+}
diff --git a/tests/block/034.out b/tests/block/034.out
new file mode 100644
index 0000000..a916dd8
--- /dev/null
+++ b/tests/block/034.out
@@ -0,0 +1,2 @@
+Running block/034
+Test complete
--
2.25.1
