[PATCH v2 0/2] Fix slab-out-of-bounds Write in dbgfs_rm_context_write

[PATCH v2 0/2] Fix slab-out-of-bounds Write in dbgfs_rm_context_write

[SeongJae Park]

Changes from v1
(https://lore.kernel.org/damon/20221031182554.7882-1-sj@kernel.org/)
- Rebase on latest mm-unstable

---

This patchset is for fixing (patch 1) the syzbot-reported
slab-out-of-bounds write in dbgfs_rm_context_write[1], and adding a
selftest for the bug (patch 2).

[1] https://lore.kernel.org/damon/000000000000ede3ac05ec4abf8e@google.com/

SeongJae Park (2):
  mm/damon/dbgfs: check if rm_contexts input is for a real context
  selftests/damon: test non-context inputs to rm_contexts file

 mm/damon/dbgfs.c                              |  7 +++++++
 tools/testing/selftests/damon/Makefile        |  1 +
 .../damon/debugfs_rm_non_contexts.sh          | 19 +++++++++++++++++++
 3 files changed, 27 insertions(+)
 create mode 100755 tools/testing/selftests/damon/debugfs_rm_non_contexts.sh

-- 
2.25.1

[PATCH v2 2/2] selftests/damon: test non-context inputs to rm_contexts file

[SeongJae Park]

There was a bug[1] that triggered by writing non-context DAMON debugfs
file names to the 'rm_contexts' DAMON debugfs file.  Add a selftest for
the bug to avoid it happen again.

[1] https://lore.kernel.org/damon/000000000000ede3ac05ec4abf8e@google.com/

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 tools/testing/selftests/damon/Makefile        |  1 +
 .../damon/debugfs_rm_non_contexts.sh          | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+)
 create mode 100755 tools/testing/selftests/damon/debugfs_rm_non_contexts.sh

diff --git a/tools/testing/selftests/damon/Makefile b/tools/testing/selftests/damon/Makefile
index af490acc5348..838a8e49f77b 100644
--- a/tools/testing/selftests/damon/Makefile
+++ b/tools/testing/selftests/damon/Makefile
@@ -7,6 +7,7 @@ TEST_FILES = _chk_dependency.sh _debugfs_common.sh
 TEST_PROGS = debugfs_attrs.sh debugfs_schemes.sh debugfs_target_ids.sh
 TEST_PROGS += debugfs_empty_targets.sh debugfs_huge_count_read_write.sh
 TEST_PROGS += debugfs_duplicate_context_creation.sh
+TEST_PROGS += debugfs_rm_non_contexts.sh
 TEST_PROGS += sysfs.sh
 TEST_PROGS += reclaim.sh lru_sort.sh
 
diff --git a/tools/testing/selftests/damon/debugfs_rm_non_contexts.sh b/tools/testing/selftests/damon/debugfs_rm_non_contexts.sh
new file mode 100755
index 000000000000..48b7af6b022c
--- /dev/null
+++ b/tools/testing/selftests/damon/debugfs_rm_non_contexts.sh
@@ -0,0 +1,19 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+source _debugfs_common.sh
+
+# Test putting non-ctx files/dirs to rm_contexts file
+# ===================================================
+
+dmesg -C
+
+for file in "$DBGFS/"*
+do
+	echo "$(basename "$f")" > "$DBGFS/rm_contexts"
+	if dmesg | grep -q BUG
+	then
+		dmesg
+		exit 1
+	fi
+done
-- 
2.25.1