mm/damon/core: add damon_new_region() debug_sanity check

damon_new_region() is supposed to be called with only valid address range
arguments.  Do the check under DAMON_DEBUG_SANITY.

Link: https://lkml.kernel.org/r/20260306152914.86303-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/damon/core.c b/mm/damon/core.c
index 71ccea40368da7c3e18f28be0055ac5173074fb3..53b573b915c7004a70a295ef38e8b603db1f7748 100644 (file)
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -109,6 +109,17 @@ int damon_select_ops(struct damon_ctx *ctx, enum damon_ops_id id)
        return err;
 }
 
+#ifdef CONFIG_DAMON_DEBUG_SANITY
+static void damon_verify_new_region(unsigned long start, unsigned long end)
+{
+       WARN_ONCE(start >= end, "start %lu >= end %lu\n", start, end);
+}
+#else
+static void damon_verify_new_region(unsigned long start, unsigned long end)
+{
+}
+#endif
+
 /*
  * Construct a damon_region struct
  *
@@ -118,6 +129,7 @@ struct damon_region *damon_new_region(unsigned long start, unsigned long end)
 {
        struct damon_region *region;
 
+       damon_verify_new_region(start, end);
        region = kmem_cache_alloc(damon_region_cache, GFP_KERNEL);
        if (!region)
                return NULL;