INFO: task syz-executor.5:24881 blocked for more than 143 seconds. Not tainted 5.10.0-rc4-next-20201123-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.5 state:D stack:28856 pid:24881 ppid: 8514 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:4316 [inline] __schedule+0x896/0x2050 kernel/sched/core.c:5067 schedule+0xcf/0x270 kernel/sched/core.c:5146 io_uring_cancel_files fs/io_uring.c:8745 [inline] io_uring_cancel_task_requests fs/io_uring.c:8797 [inline] __io_uring_files_cancel+0xc4d/0x14b0 fs/io_uring.c:8893 io_uring_files_cancel include/linux/io_uring.h:51 [inline] exit_files+0xe4/0x170 fs/file.c:456 do_exit+0xb61/0x29f0 kernel/exit.c:818 do_group_exit+0x125/0x310 kernel/exit.c:920 get_signal+0x3ec/0x2010 kernel/signal.c:2770 arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:811 handle_signal_work kernel/entry/common.c:144 [inline] exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x124/0x200 kernel/entry/common.c:198 syscall_exit_to_user_mode+0x36/0x260 kernel/entry/common.c:275 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45deb9 RSP: 002b:00007ffab09d5cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000118bf28 RCX: 000000000045deb9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000118bf28 RBP: 000000000118bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffeeb61faff R14: 00007ffab09d69c0 R15: 000000000118bf2c Showing all locks held in the system: 1 lock held by khungtaskd/1656: #0: ffffffff8b339e60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6254 2 locks held by systemd-journal/4892: 1 lock held by in:imklog/8173: #0: ffff88801cd814f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:932 2 locks held by agetty/8185: #0: ffff88802149a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:266 #1: ffffc90000f8c2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x21d/0x1aa0 drivers/tty/n_tty.c:2158 2 locks held by kworker/u4:8/22916: #0: ffff8880b9f34f98 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1318 [inline] #0: ffff8880b9f34f98 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x217/0x2050 kernel/sched/core.c:4984 #1: ffff8880b9f20088 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x305/0x440 kernel/sched/psi.c:833 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1656 Comm: khungtaskd Not tainted 5.10.0-rc4-next-20201123-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:147 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:253 [inline] watchdog+0xd89/0xf30 kernel/hung_task.c:338 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4892 Comm: systemd-journal Not tainted 5.10.0-rc4-next-20201123-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:virt_to_head_page include/linux/mm.h:866 [inline] RIP: 0010:___cache_free+0xb/0x4a0 mm/slub.c:3161 Code: 0b ff ff ff 8b 44 24 04 0b 05 11 de 43 0d eb cc e8 8a 31 37 07 66 2e 0f 1f 84 00 00 00 00 00 41 57 41 56 41 55 41 54 49 89 fc <48> 89 f7 55 53 48 89 f3 48 83 ec 18 48 89 54 24 08 e8 df ff 7d ff RSP: 0018:ffffc9000a3e7d58 EFLAGS: 00000a06 RAX: 1ffff11014ce51b8 RBX: 0000000000000008 RCX: ffffea000299c9bf RDX: ffffffff81b2f105 RSI: ffff8880a6728dc0 RDI: ffff888010cc9c80 RBP: 0000000000000000 R08: 0000000000000003 R09: ffffffff81b2f105 R10: 0000000000000000 R11: 0000000000000000 R12: ffff888010cc9c80 R13: ffffc9000a3e7db8 R14: ffffea0000000000 R15: ffff8880a6db2000 FS: 00007fccf57648c0(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fccf2c6f020 CR3: 0000000025e59000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: qlink_free mm/kasan/quarantine.c:149 [inline] qlist_free_all+0x5a/0xc0 mm/kasan/quarantine.c:168 quarantine_reduce+0x17e/0x200 mm/kasan/quarantine.c:261 __kasan_kmalloc.constprop.0+0x9e/0xd0 mm/kasan/common.c:458 lsm_cred_alloc security/security.c:533 [inline] security_prepare_creds+0x104/0x180 security/security.c:1632 prepare_creds+0x509/0x730 kernel/cred.c:285 access_override_creds fs/open.c:353 [inline] do_faccessat+0x3d7/0x820 fs/open.c:417 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fccf4a209c7 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:00007fffa2eac808 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007fffa2eaf720 RCX: 00007fccf4a209c7 RDX: 00007fccf5491a00 RSI: 0000000000000000 RDI: 000055fed93979a3 RBP: 00007fffa2eac840 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fffa2eaf720 R15: 00007fffa2eacd30