INFO: task syz-executor.0:7796 blocked for more than 143 seconds. Not tainted 5.9.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.0 state:D stack:29104 pid: 7796 ppid: 338 flags:0x80004006 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x889/0x1f70 kernel/sched/core.c:4527 schedule+0xcd/0x2b0 kernel/sched/core.c:4602 wdm_flush+0x2e9/0x3c0 drivers/usb/class/cdc-wdm.c:590 filp_close+0xb4/0x170 fs/open.c:1276 close_files fs/file.c:401 [inline] put_files_struct fs/file.c:429 [inline] put_files_struct+0x1d0/0x350 fs/file.c:426 exit_files+0x7e/0xa0 fs/file.c:458 do_exit+0xb75/0x2890 kernel/exit.c:801 do_group_exit+0x125/0x310 kernel/exit.c:903 get_signal+0x42d/0x1f10 kernel/signal.c:2757 arch_do_signal+0x88/0x1a00 arch/x86/kernel/signal.c:811 exit_to_user_mode_loop kernel/entry/common.c:135 [inline] exit_to_user_mode_prepare+0xf9/0x150 kernel/entry/common.c:166 syscall_exit_to_user_mode+0x36/0x260 kernel/entry/common.c:241 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d5b9 Code: Bad RIP value. RSP: 002b:00007fc1fa2f6cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000118cf48 RCX: 000000000045d5b9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000118cf48 RBP: 000000000118cf40 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffc2292c49f R14: 00007fc1fa2f79c0 R15: 000000000118cf4c Showing all locks held in the system: 1 lock held by khungtaskd/23: #0: ffffffff87313620 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x264 kernel/locking/lockdep.c:5825 1 lock held by in:imklog/225: #0: ffff8881c8018ff0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:930 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 23 Comm: khungtaskd Not tainted 5.9.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xf6/0x16e lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x74/0xb6 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1da/0x1f4 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xd6a/0xfd0 kernel/hung_task.c:295 kthread+0x392/0x470 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 108 Comm: systemd-journal Not tainted 5.9.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:unwind_next_frame+0x10b2/0x1f60 arch/x86/kernel/unwind_orc.c:590 Code: 0f 9e c1 40 84 f6 40 0f 95 c6 41 84 f1 0f 85 fb 0b 00 00 83 e0 07 38 c1 40 0f 9e c6 84 c9 0f 95 c0 40 84 c6 0f 85 e4 0b 00 00 <49> 0f bf 70 02 48 89 df 4c 01 e6 e8 ee ed ff ff 84 c0 0f 85 8f fd RSP: 0018:ffff8881d21ef960 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff8881d21efa38 RCX: 0000000000000000 RDX: ffff8881d21efa78 RSI: 0000000000000001 RDI: ffffffff885b7384 RBP: 1ffff1103a43df34 R08: ffffffff885b7382 R09: 0000000000000001 R10: 000000000001d731 R11: ffff8881d21efdb8 R12: ffff8881d21efdb8 R13: ffff8881d21efa6d R14: ffff8881d21efa88 R15: 0000000000000001 FS: 00007f1e196708c0(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1e16fbe000 CR3: 00000001d229b000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_stack_walk+0x81/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:123 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xf3/0x130 mm/kasan/common.c:422 slab_free_hook mm/slub.c:1548 [inline] slab_free_freelist_hook+0x53/0x140 mm/slub.c:1581 slab_free mm/slub.c:3142 [inline] kmem_cache_free+0x82/0x490 mm/slub.c:3158 __put_cred+0x1de/0x250 kernel/cred.c:148 put_cred include/linux/cred.h:287 [inline] put_cred include/linux/cred.h:280 [inline] revert_creds+0x1a8/0x1f0 kernel/cred.c:598 do_faccessat+0x2ca/0x820 fs/open.c:464 do_syscall_64+0x2d/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f1e1892c9c7 Code: 83 c4 08 48 3d 01 f0 ff ff 73 01 c3 48 8b 0d c8 d4 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 b8 15 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 d4 2b 00 f7 d8 64 89 01 48 RSP: 002b:00007ffc79d4dd48 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffc79d50d70 RCX: 00007f1e1892c9c7 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000055c1ebc6d9a3 RBP: 00007ffc79d4de90 R08: 000055c1ebc633e5 R09: 0000000000000018 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 000055c1ed7fe8a0 R15: 00007ffc79d4e380