FYI, we noticed the following commit (built with gcc-7): commit: a3232987fdbf0bede92a9d7c7e2db99a5084d31b ("drm/bochs: Convert bochs driver to |struct drm_gem_vram_object|") git://anongit.freedesktop.org/drm/drm-misc drm-misc-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): +-----------------------------------------------------------------------------+------------+------------+ | | 3f87330e50 | a3232987fd | +-----------------------------------------------------------------------------+------------+------------+ | boot_successes | 16 | 0 | | boot_failures | 0 | 16 | | WARNING:at_drivers/gpu/drm/ttm/ttm_bo.c:#ttm_bo_validate[ttm] | 0 | 16 | | RIP:ttm_bo_validate[ttm] | 0 | 16 | | WARNING:at_drivers/dma-buf/reservation.c:#reservation_object_reserve_shared | 0 | 16 | | RIP:reservation_object_reserve_shared | 0 | 16 | | WARNING:suspicious_RCU_usage | 0 | 16 | | include/linux/reservation.h:#suspicious_rcu_dereference_protected()usage | 0 | 16 | | WARNING:at_drivers/dma-buf/reservation.c:#reservation_object_add_excl_fence | 0 | 16 | | RIP:reservation_object_add_excl_fence | 0 | 16 | +-----------------------------------------------------------------------------+------------+------------+ If you fix the issue, kindly add following tag Reported-by: kernel test robot <lkp(a)intel.com&gt; [ 10.171773] WARNING: CPU: 0 PID: 403 at drivers/gpu/drm/ttm/ttm_bo.c:1161 ttm_bo_validate+0x41/0x141 [ttm] [ 10.173555] Modules linked in: parport_pc parport bochs_drm(+) drm_vram_helper ttm drm_kms_helper drm drm_panel_orientation_quirks fb_sys_fops psmouse button syscopyarea sysfillrect sysimgblt cfbfillrect virtio_pci(+) cfbimgblt cfbcopyarea i2c_piix4 fb fbdev i2c_core [ 10.177221] CPU: 0 PID: 403 Comm: modprobe Tainted: G T 5.1.0-rc5-01639-ga3232987 #23 [ 10.178618] RIP: 0010:ttm_bo_validate+0x41/0x141 [ttm] [ 10.179421] Code: 00 00 00 48 89 44 24 70 31 c0 83 3d 8e 52 5b e2 00 74 19 48 8b 87 00 02 00 00 83 ce ff 48 8d 78 70 e8 2e f9 f8 e0 85 c0 75 02 <0f> 0b 48 8d 73 30 4c 89 e7 48 8d 54 24 0c e8 25 e4 ff ff 84 c0 0f [ 10.182267] RSP: 0018:ffffc9000077f928 EFLAGS: 00010246 [ 10.183125] RAX: 0000000000000000 RBX: ffff88807dad5a38 RCX: 0000000000000000 [ 10.184211] RDX: 0000000000000246 RSI: ffff88807dad5cb0 RDI: ffff88807e4c6538 [ 10.185299] RBP: ffffc9000077f9c0 R08: 00000000c5611196 R09: 0000000000000006 [ 10.186399] R10: 0000000000000000 R11: ffff88807dae2838 R12: ffff88807dad5df8 [ 10.187492] R13: 0000000000000300 R14: 0000000000000400 R15: 0000000034325258 [ 10.188618] FS: 00007fca184c6700(0000) GS:ffff888077a00000(0000) knlGS:0000000000000000 [ 10.189901] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 10.190811] CR2: 00007ffd685c2000 CR3: 000000007e73a000 CR4: 00000000000406f0 [ 10.191945] Call Trace: [ 10.192365] ? kvm_sched_clock_read+0x5/0xd [ 10.193035] ? get_lock_stats+0x11/0x3f [ 10.193674] drm_gem_vram_pin+0x77/0xa2 [drm_vram_helper] [ 10.194550] drm_gem_vram_driver_gem_prime_vmap+0xe/0x39 [drm_vram_helper] [ 10.195671] drm_gem_vmap+0x36/0x43 [drm] [ 10.196347] drm_client_framebuffer_create+0xc6/0x1ca [drm] [ 10.197290] drm_fb_helper_generic_probe+0x4c/0x157 [drm_kms_helper] [ 10.198327] __drm_fb_helper_initial_config_and_unlock+0x307/0x442 [drm_kms_helper] [ 10.199549] drm_fbdev_client_hotplug+0xc8/0x115 [drm_kms_helper] [ 10.200546] drm_fbdev_generic_setup+0xc4/0xf1 [drm_kms_helper] [ 10.201464] bochs_pci_probe+0x123/0x143 [bochs_drm] [ 10.202218] local_pci_probe+0x34/0x75 [ 10.202810] pci_device_probe+0xf8/0x150 [ 10.203432] really_probe+0x199/0x360 [ 10.204015] driver_probe_device+0xcf/0xff [ 10.204660] device_driver_attach+0x38/0x4f [ 10.205334] __driver_attach+0x105/0x10d [ 10.205937] ? device_driver_attach+0x4f/0x4f [ 10.206647] bus_for_each_dev+0x6c/0x9e [ 10.207245] bus_add_driver+0x125/0x1d4 [ 10.207870] ? 0xffffffffa009e000 [ 10.208398] driver_register+0x94/0xc6 [ 10.208979] ? 0xffffffffa009e000 [ 10.209507] do_one_initcall+0x10e/0x297 [ 10.210085] ? rcu_read_lock_sched_held+0x58/0x5e [ 10.210771] ? kmem_cache_alloc_trace+0x21b/0x25b [ 10.211478] do_init_module+0x59/0x491 [ 10.212047] load_module+0x1178/0x138a [ 10.212642] ? __se_sys_init_module+0x103/0x13e [ 10.213318] __se_sys_init_module+0x103/0x13e [ 10.213987] do_syscall_64+0x78/0x188 [ 10.214527] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 10.215261] RIP: 0033:0x7fca17fe0bca [ 10.215794] Code: 48 8b 0d 79 32 2c 00 31 d2 48 29 c2 64 89 11 48 83 c8 ff eb ea 90 90 90 90 90 90 90 90 90 90 90 49 89 ca b8 af 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 46 32 2c 00 31 d2 48 29 c2 64 [ 10.218407] RSP: 002b:00007ffc21228fd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000af [ 10.219537] RAX: ffffffffffffffda RBX: 00000000006115d0 RCX: 00007fca17fe0bca [ 10.220605] RDX: 0000000000611700 RSI: 0000000000048620 RDI: 00007fca1847c000 [ 10.221709] RBP: 0000000000611700 R08: 00000000ffffffff R09: 0000000000000001 [ 10.222758] R10: 00007fca17fd3100 R11: 0000000000000246 R12: 000000000060f150 [ 10.223770] R13: 000000000060f1f0 R14: 0000000000000000 R15: 00000000006115e8 [ 10.224803] irq event stamp: 23288 [ 10.225321] hardirqs last enabled at (23287): [<ffffffff811ad400>] kmem_cache_alloc_trace+0x133/0x25b [ 10.226681] hardirqs last disabled at (23288): [<ffffffff81001621>] trace_hardirqs_off_thunk+0x1a/0x1c [ 10.228034] softirqs last enabled at (23228): [<ffffffff81c003cf>] __do_softirq+0x3cf/0x411 [ 10.229227] softirqs last disabled at (23215): [<ffffffff8107de91>] irq_exit+0x66/0xe1 [ 10.230358] ---[ end trace cf9927661fdd2749 ]--- To reproduce: # build kernel cd linux cp config-5.1.0-rc5-01639-ga3232987 .config make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 olddefconfig make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 prepare make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 modules_prepare make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 SHELL=/bin/bash make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 bzImage git clone https://github.com/intel/lkp-tests.git cd lkp-tests bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email Thanks, lkp