[PATCH v2] lkdtm/core: fix resource leaks on module init error path

[Jiangshan Yi]

When lkdtm_register_cpoint() fails, the out_err path only removes
debugfs but leaks the kmem_caches from lkdtm_heap_init() /
lkdtm_usercopy_init() and the lkdtm_kernel_info string, because the
kernel never calls module_exit() on init failure.

Add the missing cleanup calls to out_err.  Drop __exit from
lkdtm_heap_exit() and lkdtm_usercopy_exit() to avoid section mismatch:
these functions are now called from __init context, and .exit.text is
discarded for built-in builds.

Fixes: 039a1c42058d ("lkdtm: Relocate code to subdirectory")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jiangshan Yi <yijiangshan@xxxxxxxxxx>

---

Changes in v2:
  - Drop __exit annotation to fix section mismatch when built-in.

 drivers/misc/lkdtm/core.c      | 3 +++
 drivers/misc/lkdtm/heap.c      | 2 +-
 drivers/misc/lkdtm/lkdtm.h     | 4 ++--
 drivers/misc/lkdtm/usercopy.c  | 2 +-
 4 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c
index ededa32d6744..1e3a5e45e3c2 100644
--- a/drivers/misc/lkdtm/core.c
+++ b/drivers/misc/lkdtm/core.c
@@ -468,6 +468,9 @@ static int __init lkdtm_module_init(void)

 out_err:
 	debugfs_remove_recursive(lkdtm_debugfs_root);
+	lkdtm_heap_exit();
+	lkdtm_usercopy_exit();
+	kfree(lkdtm_kernel_info);
 	return ret;
 }

diff --git a/drivers/misc/lkdtm/heap.c b/drivers/misc/lkdtm/heap.c
index 9e358d15f4fb..d01e3a3e3e3e 100644
--- a/drivers/misc/lkdtm/heap.c
+++ b/drivers/misc/lkdtm/heap.c
@@ -363,7 +363,7 @@ void __init lkdtm_heap_init(void)
 	b_cache = kmem_cache_create("lkdtm-heap-b", 64, 0, SLAB_NO_MERGE, NULL);
 }

-void __exit lkdtm_heap_exit(void)
+void lkdtm_heap_exit(void)
 {
 	kmem_cache_destroy(double_free_cache);
 	kmem_cache_destroy(a_cache);
diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h
index 3a57c4e5e978..e3a3e3c3e3e3 100644
--- a/drivers/misc/lkdtm/lkdtm.h
+++ b/drivers/misc/lkdtm/lkdtm.h
@@ -89,9 +89,9 @@ extern struct crashtype_category powerpc_crashtypes;
 /* Each category's init/exit routines. */
 void __init lkdtm_bugs_init(int *recur_param);
 void __init lkdtm_heap_init(void);
-void __exit lkdtm_heap_exit(void);
+void lkdtm_heap_exit(void);
 void __init lkdtm_perms_init(void);
 void __init lkdtm_usercopy_init(void);
-void __exit lkdtm_usercopy_exit(void);
+void lkdtm_usercopy_exit(void);

 /* Special declaration for function-in-rodata. */
 void lkdtm_rodata_do_nothing(void);
diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c
index 2f3c5034a3e3..e3a3e3e3e3e3 100644
--- a/drivers/misc/lkdtm/usercopy.c
+++ b/drivers/misc/lkdtm/usercopy.c
@@ -433,7 +433,7 @@ void __init lkdtm_usercopy_init(void)
 					   NULL);
 }

-void __exit lkdtm_usercopy_exit(void)
+void lkdtm_usercopy_exit(void)
 {
 	kmem_cache_destroy(whitelist_cache);
 }
--
2.25.1