watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [kworker/1:0:18] Modules linked in: irq event stamp: 485116 hardirqs last enabled at (485115): [] asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 hardirqs last disabled at (485116): [] irqentry_enter+0x1d/0x50 kernel/entry/common.c:318 softirqs last enabled at (480592): [] asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706 softirqs last disabled at (480575): [] asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706 CPU: 1 PID: 18 Comm: kworker/1:0 Not tainted 5.8.0-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 Workqueue: events drm_fb_helper_dirty_work RIP: 0010:csd_lock_wait kernel/smp.c:108 [inline] RIP: 0010:smp_call_function_many_cond+0x7c4/0x990 kernel/smp.c:555 Code: 0a 00 85 ed 74 4d 48 b8 00 00 00 00 00 fc ff df 4d 89 f4 4c 89 f5 49 c1 ec 03 83 e5 07 49 01 c4 83 c5 03 e8 1e fa 0a 00 f3 90 <41> 0f b6 04 24 40 38 c5 7c 08 84 c0 0f 85 a2 00 00 00 8b 43 08 31 RSP: 0018:ffffc900004cf980 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff88802d040fe0 RCX: ffffffff816922d8 RDX: ffff88802c2985c0 RSI: ffffffff816922b2 RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000000 R09: ffffffff8aaf8873 R10: 0000000000000000 R11: 0000000000000183 R12: ffffed1005a081fd R13: 0000000000000002 R14: ffff88802d040fe8 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff88802cf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcb7fd869de CR3: 000000002988c000 CR4: 0000000000350ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: smp_call_function_many kernel/smp.c:577 [inline] smp_call_function kernel/smp.c:599 [inline] on_each_cpu+0x4a/0x240 kernel/smp.c:698 __purge_vmap_area_lazy+0x11e/0x1f20 mm/vmalloc.c:1367 try_purge_vmap_area_lazy mm/vmalloc.c:1404 [inline] free_vmap_area_noflush+0x2bc/0x370 mm/vmalloc.c:1440 free_unmap_vmap_area mm/vmalloc.c:1453 [inline] remove_vm_area+0x1ca/0x230 mm/vmalloc.c:2204 vm_remove_mappings mm/vmalloc.c:2231 [inline] __vunmap+0x348/0xac0 mm/vmalloc.c:2293 vunmap+0x50/0x60 mm/vmalloc.c:2398 drm_gem_shmem_vunmap_locked drivers/gpu/drm/drm_gem_shmem_helper.c:323 [inline] drm_gem_shmem_vunmap+0x174/0x1c0 drivers/gpu/drm/drm_gem_shmem_helper.c:340 drm_gem_vunmap+0x81/0x130 drivers/gpu/drm/drm_gem.c:1275 drm_client_buffer_vunmap+0x51/0xa0 drivers/gpu/drm/drm_client.c:340 drm_fb_helper_dirty_work+0x5c4/0x810 drivers/gpu/drm/drm_fb_helper.c:442 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294