[PATCH v4 01/10] lib/test_vmalloc: add no_block_alloc_test case

Uladzislau Rezki (Sony)
2025-10-07T12:20:45Z

Introduce a new test case "no_block_alloc_test" that verifies
non-blocking allocations using __vmalloc() with GFP_ATOMIC and
GFP_NOWAIT flags.

It is recommended to build kernel with CONFIG_DEBUG_ATOMIC_SLEEP
enabled to help catch "sleeping while atomic" issues. This test
ensures that memory allocation logic under atomic constraints
does not inadvertently sleep.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
---
lib/test_vmalloc.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)

diff --git a/lib/test_vmalloc.c b/lib/test_vmalloc.c
index 2815658ccc37..aae5f4910aff 100644
--- a/lib/test_vmalloc.c
+++ b/lib/test_vmalloc.c
@@ -54,6 +54,7 @@ __param(int, run_test_mask, 7,
"\t\tid: 256, name: kvfree_rcu_1_arg_vmalloc_test\n"
"\t\tid: 512, name: kvfree_rcu_2_arg_vmalloc_test\n"
"\t\tid: 1024, name: vm_map_ram_test\n"
+ "\t\tid: 2048, name: no_block_alloc_test\n"
/* Add a new test case description here. */
);

@@ -283,6 +284,30 @@ static int fix_size_alloc_test(void)
return 0;
}

+static int no_block_alloc_test(void)
+{
+ void *ptr;
+ int i;
+
+ for (i = 0; i < test_loop_count; i++) {
+ bool use_atomic = !!(get_random_u8() % 2);
+ gfp_t gfp = use_atomic ? GFP_ATOMIC : GFP_NOWAIT;
+ unsigned long size = (nr_pages > 0 ? nr_pages : 1) * PAGE_SIZE;
+
+ preempt_disable();
+ ptr = __vmalloc(size, gfp);
+ preempt_enable();
+
+ if (!ptr)
+ return -1;
+
+ *((__u8 *)ptr) = 0;
+ vfree(ptr);
+ }
+
+ return 0;
+}
+
static int
pcpu_alloc_test(void)
{
@@ -411,6 +436,7 @@ static struct test_case_desc test_case_array[] = {
{ "kvfree_rcu_1_arg_vmalloc_test", kvfree_rcu_1_arg_vmalloc_test, },
{ "kvfree_rcu_2_arg_vmalloc_test", kvfree_rcu_2_arg_vmalloc_test, },
{ "vm_map_ram_test", vm_map_ram_test, },
+ { "no_block_alloc_test", no_block_alloc_test, true },
/* Add a new test case here. */
};

--
2.47.3