FYI, we noticed the following commit (built with gcc-5): commit: b6957ee36c281c84f9fdd3deda5a78ddf303c296 ("locking/lockdep: Zap lock classes even with lock debugging disabled") https://github.com/bvanassche/linux for-next in testcase: trinity with following parameters: runtime: 300s test-description: Trinity is a linux system call fuzz tester. test-url: http://codemonkey.org.uk/projects/trinity/ on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 2G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +-----------------------------------------------------------------------------+------------+------------+ | | 0d498b752b | b6957ee36c | +-----------------------------------------------------------------------------+------------+------------+ | boot_successes | 0 | 0 | | boot_failures | 16 | 12 | | BUG:kernel_in_stage | 4 | 1 | | kobject(#):tried_to_init_an_initialized_object,something_is_seriously_wrong | 12 | 11 | | BUG:KASAN:use-after-free_in_t | 12 | 11 | | WARNING:at_kernel/locking/lockdep.c:#lockdep_unregister_key | 0 | 11 | | RIP:lockdep_unregister_key | 0 | 11 | +-----------------------------------------------------------------------------+------------+------------+ [ 526.537883] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:4920 lockdep_unregister_key+0x1dd/0x390 [ 526.540038] CPU: 0 PID: 1 Comm: swapper Tainted: G B T 5.1.0-rc3-00007-gb6957ee3 #1 [ 526.540038] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 526.540038] RIP: 0010:lockdep_unregister_key+0x1dd/0x390 [ 526.540038] Code: 48 c1 e8 03 42 80 3c 30 00 0f 85 81 01 00 00 48 8b 1b 48 85 db 75 c2 48 83 c5 01 48 89 2d 8b e6 d0 08 48 83 05 93 e6 d0 08 01 <0f> 0b 48 83 05 91 e6 d0 08 01 48 83 05 91 e6 d0 08 01 ba 01 00 00 [ 526.540038] RSP: 0000:ffff8880678af800 EFLAGS: 00010002 [ 526.540038] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff8534af18 [ 526.540038] RDX: 1ffffffff14c7b9d RSI: ffffffff814122f5 RDI: ffff8880678a10e8 [ 526.540038] RBP: ffffffff8a63dce8 R08: fffffbfff0e34159 R09: fffffbfff0e34159 [ 526.540038] R10: 0000000006f66365 R11: fffffbfff0e34158 R12: ffff888057b00b50 [ 526.540038] R13: 0000000000000202 R14: ffff8880678a0000 R15: ffffffff8a3b61c8 [ 526.540038] FS: 0000000000000000(0000) GS:ffffffff870d9000(0000) knlGS:0000000000000000 [ 526.540038] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 526.540038] CR2: 0000000000000000 CR3: 0000000007028000 CR4: 00000000000006f0 [ 526.540038] Call Trace: [ 526.540038] blk_free_flush_queue+0x2c/0x80 [ 526.540038] blk_mq_exit_hctx+0x295/0x420 [ 526.540038] blk_mq_free_queue+0x3a5/0x530 [ 526.540038] blk_cleanup_queue+0x1da/0x290 [ 526.540038] __scsi_remove_device+0x118/0x470 [ 526.540038] scsi_forget_host+0x16c/0x220 [ 526.540038] scsi_remove_host+0x124/0x300 [ 526.540038] sdebug_driver_remove+0x63/0x300 [ 526.540038] ? driver_sysfs_add+0x12b/0x380 [ 526.540038] ? config_cdb_len+0x3b0/0x3b0 [ 526.540038] really_probe+0x21a/0xbd0 [ 526.540038] ? resp_inquiry+0x3d80/0x3d80 [ 526.540038] driver_probe_device+0x115/0x2d0 [ 526.540038] __device_attach_driver+0x1dc/0x260 [ 526.540038] ? driver_allows_async_probing+0xe0/0xe0 [ 526.540038] bus_for_each_drv+0x16b/0x210 [ 526.540038] ? subsys_find_device_by_id+0x3e0/0x3e0 [ 526.540038] __device_attach+0x24a/0x370 [ 526.540038] ? device_bind_driver+0x100/0x100 [ 526.540038] ? kobject_uevent_env+0x39a/0x1500 [ 526.540038] device_initial_probe+0x1e/0x30 [ 526.540038] bus_probe_device+0x222/0x2d0 [ 526.540038] device_add+0xee1/0x18b0 [ 526.540038] ? dev_set_name+0xf0/0xf0 [ 526.540038] ? __raw_spin_lock_init+0x38/0x110 [ 526.540038] ? __init_waitqueue_head+0x45/0xa0 [ 526.540038] device_register+0x29/0x40 [ 526.540038] sdebug_add_adapter+0x22b/0x5f0 [ 526.540038] ? kobject_uevent+0x20/0x30 [ 526.540038] scsi_debug_init+0xd3c/0xfbd [ 526.540038] ? init_osst+0x24a/0x24a [ 526.540038] ? kobject_uevent+0x20/0x30 [ 526.540038] ? osst_setup+0x346/0x346 [ 526.540038] ? init_osst+0x24a/0x24a [ 526.540038] do_one_initcall+0x138/0x2eb [ 526.540038] ? start_kernel+0x933/0x933 [ 526.540038] ? reacquire_held_locks+0x550/0x550 [ 526.540038] ? lock_acquire+0xc3/0x180 [ 526.540038] ? __usermodehelper_set_disable_depth+0x1c/0x60 [ 526.540038] kernel_init_freeable+0x390/0x4b2 [ 526.540038] ? rest_init+0x200/0x200 [ 526.540038] kernel_init+0x17/0x250 [ 526.540038] ? rest_init+0x200/0x200 [ 526.540038] ? rest_init+0x200/0x200 [ 526.540038] ret_from_fork+0x1f/0x30 [ 526.540038] ---[ end trace 6914c1771d2db339 ]--- To reproduce: # build kernel cd linux cp config-5.1.0-rc3-00007-gb6957ee3 .config make HOSTCC=gcc-5 CC=gcc-5 ARCH=x86_64 olddefconfig make HOSTCC=gcc-5 CC=gcc-5 ARCH=x86_64 prepare make HOSTCC=gcc-5 CC=gcc-5 ARCH=x86_64 modules_prepare make HOSTCC=gcc-5 CC=gcc-5 ARCH=x86_64 SHELL=/bin/bash make HOSTCC=gcc-5 CC=gcc-5 ARCH=x86_64 bzImage git clone https://github.com/intel/lkp-tests.git cd lkp-tests bin/lkp qemu -k job-script # job-script is attached in this email Thanks, Rong Chen