INFO: task syz.0.707:9220 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.707 state:D stack:28296 pid:9220 tgid:9218 ppid:5853 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7058 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x81b/0x1060 kernel/locking/mutex.c:760 sync_bdevs+0xfd/0x360 block/bdev.c:1288 ksys_sync+0xb2/0x150 fs/sync.c:105 __do_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5d5af8ebe9 RSP: 002b:00007f5d5be67038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f5d5b1b6090 RCX: 00007f5d5af8ebe9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f5d5b1b6090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5d5b1b6128 R14: 00007f5d5b1b6090 R15: 00007fffcb347228 Showing all locks held in the system: 2 locks held by kworker/u8:1/13: #0: ffff88801b881148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90000127d10 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 1 lock held by khungtaskd/31: #0: ffffffff8e5c1220 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e5c1220 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e5c1220 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 2 locks held by getty/5604: #0: ffff88814ce820a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 1 lock held by udevd/6949: #0: ffff8881437ad358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x41a/0xe40 block/bdev.c:945 1 lock held by syz.0.707/9220: #0: ffff8881437ad358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0xfd/0x360 block/bdev.c:1288 1 lock held by syz.2.1294/11802: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline] watchdog+0xf0e/0x1260 kernel/hung_task.c:491 kthread+0x3c2/0x780 kernel/kthread.c:463 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5830 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:avtab_search_node+0x279/0x4b0 security/selinux/ss/avtab.c:188 Code: fd 66 41 39 ec 0f 82 3c 01 00 00 e8 51 92 20 fd 48 8d 7b 10 48 89 f8 48 c1 e8 03 42 80 3c 28 00 0f 85 ee 01 00 00 48 8b 5b 10 <48> 85 db 0f 84 14 01 00 00 e8 29 92 20 fd 48 89 d8 48 c1 e8 03 42 RSP: 0018:ffffc900032e76e0 EFLAGS: 00000246 RAX: 1ffff110065ab248 RBX: ffff8880326286b8 RCX: ffffffff849af990 RDX: ffff8880343fc880 RSI: ffffffff849af99f RDI: ffff888032d59240 RBP: 000000000000035a R08: 0000000000000002 R09: 000000000000043d R10: 000000000000035a R11: 0000000000000000 R12: 000000000000043d R13: dffffc0000000000 R14: 00000000000001e4 R15: 000000000000000f FS: 000055555a41f500(0000) GS:ffff8881246b9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f985a7701d4 CR3: 0000000074a3b000 CR4: 00000000003526f0 Call Trace: context_struct_compute_av+0x622/0x1270 security/selinux/ss/services.c:664 security_compute_av+0x5ec/0x11d0 security/selinux/ss/services.c:1177 avc_compute_av+0x83/0x7f0 security/selinux/avc.c:992 avc_perm_nonode+0xab/0x180 security/selinux/avc.c:1117 avc_has_perm_noaudit+0x2de/0x3b0 security/selinux/avc.c:1160 avc_has_perm+0xbe/0x1f0 security/selinux/avc.c:1195 inode_has_perm+0x168/0x1d0 security/selinux/hooks.c:1681 file_has_perm+0x2e4/0x350 security/selinux/hooks.c:1777 selinux_revalidate_file_permission security/selinux/hooks.c:3766 [inline] selinux_file_permission+0x498/0x660 security/selinux/hooks.c:3787 security_file_permission+0x1e3/0x210 security/security.c:2874 rw_verify_area+0xb9/0x6c0 fs/read_write.c:473 vfs_read+0x150/0xcf0 fs/read_write.c:563 ksys_read+0x1f8/0x250 fs/read_write.c:715 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff86778d5bd Code: a8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb b5 e8 a8 48 00 00 0f 1f 84 00 00 00 00 00 80 3d a1 af 1f 00 00 74 17 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 5b c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec RSP: 002b:00007ffe2ff2b2d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff86778d5bd RDX: 0000000000000004 RSI: 00007ffe2ff2b2ec RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000013f8c R09: 00007ff868588000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe2ff2b700 R13: 0000000000000004 R14: 00007ffe2ff2b2ec R15: 00007ffe2ff2b380