As Marco pointed out, commit 2810c1e99867 ("kunit: Fix wild-memory-access
bug in kunit_free_suite_set()") causes test suites to run while the test
module is still in MODULE_STATE_COMING. In that state, the module
is not fully initialized, lacking sysfs, module_memory, args, init
function which causes null-ptr-deref of using fake devices below.
Since load_module() notify MODULE_STATE_COMING in prepare_coming_module(),
and then init sysfs and args etc. in parse_args() and mod_sysfs_setup(),
after that it notify MODULE_STATE_LIVE in do_init_module(), and fake driver
in the test suits depend on them. So the test suits should be executed when
notify MODULE_STATE_LIVE.
But the kunit_free_suite_set() in kunit_module_exit() depends on the
success of kunit_filter_suites() in kunit_module_init(). The best practice
is to alloc and init resource when notify MODULE_STATE_COMING and free them
when notify MODULE_STATE_GOING. So split the kunit_module_exec() from
kunit_module_init() to run test suits when MODULE_STATE_LIVE, call
kunit_filter_suites() and allocate memory in kunit_module_init() and call
kunit_free_suite_set() in kunit_module_exit() to free the memory.
So if load_module() succeeds and notify module state as below, it calls
kunit_module_init(), kunit_module_exec() and kunit_module_exit(), which
will work ok. The mod->state state machine when load_module() succeeds:
kunit_filter_suites() kunit_module_exec()
MODULE_STATE_UNFORMED ---> MODULE_STATE_COMING ---> MODULE_STATE_LIVE
^ |
| |
+---------------- MODULE_STATE_GOING <---------+
kunit_free_suite_set()
If load_module() fails and notify module state as below, it call
kunit_module_init() and kunit_module_exit(), which will also work ok.
The mod->state state machine when load_module() fails at mod_sysfs_setup():
kunit_filter_suites() kunit_free_suite_set()
MODULE_STATE_UNFORMED ---> MODULE_STATE_COMING ---> MODULE_STATE_GOING
^ |
| |
+-----------------------------------------------+
general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 1 PID: 1868 Comm: modprobe Tainted: G W N 6.6.0-rc3+ #61
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
RIP: 0010:kobject_namespace+0x71/0x150
Code: 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 cd 00 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 5c 24 28 48 8d 7b 18 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 c1 00 00 00 48 8b 43 18 48 85 c0 74 79 4c 89 e7
RSP: 0018:ffff88810f797288 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000003 RSI: ffffffff847b4900 RDI: 0000000000000018
RBP: ffff88810ba08940 R08: 0000000000000001 R09: ffffed1021ef2e0f
R10: ffff88810f79707f R11: 746e756f63666572 R12: ffffffffa0241990
R13: ffff88810ba08958 R14: ffff88810ba08968 R15: ffffffff84ac6c20
FS: 00007ff9f2186540(0000) GS:ffff888119c80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff73a2cff8 CR3: 000000010b77b002 CR4: 0000000000770ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
? die_addr+0x3d/0xa0
? exc_general_protection+0x144/0x220
? asm_exc_general_protection+0x22/0x30
? kobject_namespace+0x71/0x150
kobject_add_internal+0x267/0x870
kobject_add+0x120/0x1f0
? kset_create_and_add+0x160/0x160
? __kmem_cache_alloc_node+0x1d2/0x350
? _raw_spin_lock+0x87/0xe0
? kobject_create_and_add+0x3c/0xb0
kobject_create_and_add+0x68/0xb0
module_add_driver+0x260/0x350
bus_add_driver+0x2c9/0x580
driver_register+0x133/0x460
kunit_run_tests+0xdb/0xef0
? _prb_read_valid+0x3e3/0x550
? _raw_spin_lock+0x87/0xe0
? _raw_spin_lock_bh+0xe0/0xe0
? __send_ipi_mask+0x1ba/0x450
? __pte_offset_map+0x19/0x1f0
? __pte_offset_map_lock+0xd6/0x1b0
? __kunit_test_suites_exit+0x30/0x30
? kvm_smp_send_call_func_ipi+0x68/0xc0
? do_sync_core+0x22/0x30
? smp_call_function_many_cond+0x1be/0xcf0
? __text_poke+0x890/0x890
? __text_poke+0x890/0x890
? on_each_cpu_cond_mask+0x46/0x70
? text_poke_bp_batch+0x413/0x570
? do_sync_core+0x30/0x30
? __jump_label_patch+0x34c/0x350
? mutex_unlock+0x80/0xd0
? __mutex_unlock_slowpath.constprop.0+0x2a0/0x2a0
__kunit_test_suites_init+0xc4/0x120
kunit_module_notify+0x36c/0x3b0
? __kunit_test_suites_init+0x120/0x120
? preempt_count_add+0x79/0x150
notifier_call_chain+0xbf/0x280
? kasan_quarantine_put+0x21/0x1a0
blocking_notifier_call_chain_robust+0xbb/0x140
? notifier_call_chain+0x280/0x280
? 0xffffffffa0238000
load_module+0x4af0/0x67d0
? module_frob_arch_sections+0x20/0x20
? rwsem_down_write_slowpath+0x11a0/0x11a0
? kernel_read_file+0x3ca/0x510
? __x64_sys_fspick+0x2a0/0x2a0
? init_module_from_file+0xd2/0x130
init_module_from_file+0xd2/0x130
? __ia32_sys_init_module+0xa0/0xa0
? userfaultfd_unmap_prep+0x3d0/0x3d0
? _raw_spin_lock_bh+0xe0/0xe0
idempotent_init_module+0x339/0x610
? init_module_from_file+0x130/0x130
? __fget_light+0x57/0x500
__x64_sys_finit_module+0xba/0x130
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
Fixes: 2810c1e99867 ("kunit: Fix wild-memory-access bug in kunit_free_suite_set()")
Reported-by: Marco Pagani <marpagan@xxxxxxxxxx>
Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
---
lib/kunit/test.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index 145f70219f46..8fac4783c676 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -739,7 +739,6 @@ static int kunit_module_init(struct module *mod)
struct kunit_suite_set suite_set = {
mod->kunit_suites, mod->kunit_suites + mod->num_kunit_suites,
};
- const char *action = kunit_action();
int err = 0;
suite_set = kunit_filter_suites(&suite_set,
@@ -752,16 +751,28 @@ static int kunit_module_init(struct module *mod)
mod->kunit_suites = (struct kunit_suite **)suite_set.start;
mod->num_kunit_suites = suite_set.end - suite_set.start;
- if (!action)
+ return err;
+}
+
+static void kunit_module_exec(struct module *mod)
+{
+ struct kunit_suite_set suite_set = {
+ mod->kunit_suites, mod->kunit_suites + mod->num_kunit_suites,
+ };
+ const char *action = kunit_action();
+
+ if (!action) {
kunit_exec_run_tests(&suite_set, false);
+
+ __kunit_test_suites_exit(mod->kunit_suites,
+ mod->num_kunit_suites);
+ }
else if (!strcmp(action, "list"))
kunit_exec_list_tests(&suite_set, false);
else if (!strcmp(action, "list_attr"))
kunit_exec_list_tests(&suite_set, true);
else
pr_err("kunit: unknown action '%s'\n", action);
-
- return err;
}
static void kunit_module_exit(struct module *mod)
@@ -769,11 +780,6 @@ static void kunit_module_exit(struct module *mod)
struct kunit_suite_set suite_set = {
mod->kunit_suites, mod->kunit_suites + mod->num_kunit_suites,
};
- const char *action = kunit_action();
-
- if (!action)
- __kunit_test_suites_exit(mod->kunit_suites,
- mod->num_kunit_suites);
kunit_free_suite_set(suite_set);
}
@@ -789,6 +795,7 @@ static int kunit_module_notify(struct notifier_block *nb, unsigned long val,
ret = kunit_module_init(mod);
break;
case MODULE_STATE_LIVE:
+ kunit_module_exec(mod);
break;
case MODULE_STATE_GOING:
kunit_module_exit(mod);
--
2.34.1
