On Thu, Nov 10, 2016 at 01:06:39PM -0800, Yang Shi wrote:

When running locktorture module with the below commands with kmemleak enabled:

$ modprobe locktorture torture_type=rw_lock_irq $ rmmod locktorture

The below kmemleak got caught:

root@10:~# echo scan > /sys/kernel/debug/kmemleak [ 323.197029] kmemleak: 2 new suspected memory leaks (see /sys/kernel/debug/kmemleak) root@10:~# cat /sys/kernel/debug/kmemleak unreferenced object 0xffffffc07592d500 (size 128): comm "modprobe", pid 368, jiffies 4294924118 (age 205.824s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 c3 7b 02 00 00 00 00 00 .........{...... 00 00 00 00 00 00 00 00 d7 9b 02 00 00 00 00 00 ................ backtrace: [<ffffff80081e5a88>] create_object+0x110/0x288 [<ffffff80086c6078>] kmemleak_alloc+0x58/0xa0 [<ffffff80081d5acc>] __kmalloc+0x234/0x318 [<ffffff80006fa130>] 0xffffff80006fa130 [<ffffff8008083ae4>] do_one_initcall+0x44/0x138 [<ffffff800817e28c>] do_init_module+0x68/0x1cc [<ffffff800811c848>] load_module+0x1a68/0x22e0 [<ffffff800811d340>] SyS_finit_module+0xe0/0xf0 [<ffffff80080836f0>] el0_svc_naked+0x24/0x28 [<ffffffffffffffff>] 0xffffffffffffffff unreferenced object 0xffffffc07592d480 (size 128): comm "modprobe", pid 368, jiffies 4294924118 (age 205.824s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 3b 6f 01 00 00 00 00 00 ........;o...... 00 00 00 00 00 00 00 00 23 6a 01 00 00 00 00 00 ........#j...... backtrace: [<ffffff80081e5a88>] create_object+0x110/0x288 [<ffffff80086c6078>] kmemleak_alloc+0x58/0xa0 [<ffffff80081d5acc>] __kmalloc+0x234/0x318 [<ffffff80006fa22c>] 0xffffff80006fa22c [<ffffff8008083ae4>] do_one_initcall+0x44/0x138 [<ffffff800817e28c>] do_init_module+0x68/0x1cc [<ffffff800811c848>] load_module+0x1a68/0x22e0 [<ffffff800811d340>] SyS_finit_module+0xe0/0xf0 [<ffffff80080836f0>] el0_svc_naked+0x24/0x28 [<ffffffffffffffff>] 0xffffffffffffffff

It is because cxt.lwsa and cxt.lrsa don't get freed in module_exit, so free them in lock_torture_cleanup() and free writer_tasks if reader_tasks is failed at memory allocation.

Signed-off-by: Yang Shi yang.shi@linaro.org

Good catch! Queued for review and testing.

Thanx, Paul

---

kernel/locking/locktorture.c | 6 ++++++ 1 file changed, 6 insertions(+)

diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c index f8c5af5..d3de04b 100644 --- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -780,6 +780,10 @@ static void lock_torture_cleanup(void) else lock_torture_print_module_parms(cxt.cur_ops, "End of test: SUCCESS");

• kfree(cxt.lwsa);
• kfree(cxt.lrsa);

end: torture_cleanup_end(); } @@ -924,6 +928,8 @@ static int __init lock_torture_init(void) GFP_KERNEL); if (reader_tasks == NULL) { VERBOSE_TOROUT_ERRSTRING("reader_tasks: Out of memory");

• 	kfree(writer_tasks);
  

• 	writer_tasks = NULL;
  firsterr = -ENOMEM;
  goto unwind;
  

  }

-- 2.0.2