INFO: task syz-executor.5:6794 blocked for more than 143 seconds. Not tainted 5.7.0-rc6-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28528 6794 7649 0x20020004 Call Trace: context_switch kernel/sched/core.c:3367 [inline] __schedule+0x937/0x1ff0 kernel/sched/core.c:4083 spin_unlock include/linux/spinlock.h:393 [inline] __mutex_lock_common kernel/locking/mutex.c:1032 [inline] __mutex_lock+0x7a6/0x13c0 kernel/locking/mutex.c:1103 __sched_text_start+0x8/0x8 rwlock_bug.part.0+0x90/0x90 include/linux/sched.h:1329 schedule+0xd0/0x2a0 kernel/sched/core.c:4158 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4217 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 mutex_trylock+0x2c0/0x2c0 kernel/locking/mutex.c:126 atomic64_cmpxchg include/asm-generic/atomic-instrumented.h:1463 [inline] atomic_long_cmpxchg_release include/asm-generic/atomic-long.h:424 [inline] __mutex_unlock_slowpath+0xe2/0x660 kernel/locking/mutex.c:1249 spin_unlock include/linux/spinlock.h:393 [inline] chrdev_open+0xc4/0x5c0 fs/char_dev.c:402 lock_downgrade+0x840/0x840 kernel/locking/lockdep.c:4579 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 get_fb_info.part.0+0x80/0x80 drivers/video/fbdev/core/fbmem.c:68 chrdev_open+0x219/0x5c0 fs/char_dev.c:414 cdev_put.part.0+0x50/0x50 fs/char_dev.c:364 security_file_open+0x84/0x410 security/security.c:1548 do_dentry_open+0x4ba/0x1290 fs/open.c:797 cdev_put.part.0+0x50/0x50 fs/char_dev.c:364 security_inode_permission+0xc4/0xf0 security/security.c:1253 chown_common+0x550/0x550 fs/open.c:629 inode_permission+0xab/0x500 fs/namei.c:450 do_open fs/namei.c:3229 [inline] path_openat+0x1e59/0x27d0 fs/namei.c:3346 path_lookupat.isra.0+0x530/0x530 fs/namei.c:2332 check_preemption_disabled lib/smp_processor_id.c:52 [inline] debug_smp_processor_id+0x2f/0x185 lib/smp_processor_id.c:57 perf_trace_lock+0xeb/0x4c0 include/trace/events/lock.h:39 __bfs+0x520/0x520 kernel/locking/lockdep.c:1539 __bfs+0x520/0x520 kernel/locking/lockdep.c:1539 trace_hardirqs_on_thunk+0x1a/0x1c arch/x86/entry/thunk_64.S:41 do_filp_open+0x192/0x260 fs/namei.c:3373 expand_files+0x433/0x7a0 fs/file.c:225 may_open_dev+0xf0/0xf0 fs/namei.c:2821 spin_unlock include/linux/spinlock.h:393 [inline] __alloc_fd+0x46d/0x600 fs/file.c:534 atomic_try_cmpxchg include/asm-generic/atomic-instrumented.h:694 [inline] queued_spin_lock include/asm-generic/qspinlock.h:78 [inline] do_raw_spin_lock+0x129/0x2e0 kernel/locking/spinlock_debug.c:113 rwlock_bug.part.0+0x90/0x90 include/linux/sched.h:1329 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock+0x24/0x40 kernel/locking/spinlock.c:183 spin_unlock include/linux/spinlock.h:393 [inline] __alloc_fd+0x46d/0x600 fs/file.c:534 do_sys_openat2+0x585/0x7d0 fs/open.c:1148 file_open_root+0x400/0x400 fs/open.c:1129 put_old_timespec32+0x100/0x1f0 kernel/time/time.c:854 get_old_timespec32+0x1f0/0x1f0 kernel/time/time.c:827 do_sys_open+0xc3/0x140 fs/open.c:1164 filp_open+0x70/0x70 fs/open.c:1117 __x64_sys_clock_gettime32+0x240/0x240 kernel/time/posix-timers.c:1410 trace_hardirqs_off_caller+0x55/0x230 kernel/trace/trace_preemptirq.c:73 trace_hardirqs_off_caller+0x55/0x230 kernel/trace/trace_preemptirq.c:73 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline] do_fast_syscall_32+0x270/0xe90 arch/x86/entry/common.c:396 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 INFO: lockdep is turned off. NMI backtrace for cpu 0 CPU: 0 PID: 1147 Comm: khungtaskd Not tainted 5.7.0-rc6-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+0x188/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 lapic_can_unplug_cpu.cold+0x3b/0x3b nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xa8c/0x1010 kernel/hung_task.c:289 reset_hung_task_detector+0x30/0x30 kernel/hung_task.c:243 kthread+0x388/0x470 kernel/kthread.c:268 kthread_mod_delayed_work+0x1a0/0x1a0 kernel/kthread.c:1090 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 986 Comm: kworker/u4:0 Not tainted 5.7.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet RIP: 0010:__preempt_count_add arch/x86/include/asm/preempt.h:79 [inline] RIP: 0010:rcu_read_lock_sched_notrace include/linux/rcupdate.h:717 [inline] RIP: 0010:trace_workqueue_execute_end include/trace/events/workqueue.h:108 [inline] RIP: 0010:process_one_work+0xf63/0x16a0 kernel/workqueue.c:2273 Code: 65 ff 0d e8 68 b6 7e 0f 94 c3 31 ff 89 de e8 d4 81 27 00 84 db 0f 84 e8 f9 ff ff e8 97 80 27 00 e8 86 c0 b4 ff e9 d9 f9 ff ff 88 80 27 00 65 ff 05 b9 68 b6 7e 48 8b 05 12 54 39 09 e8 a5 00 RSP: 0018:ffffc9000825fd28 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff814bb064 RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000001 RBP: ffff8880a14ce048 R08: ffff888043dec3c0 R09: fffffbfff1513239 R10: ffffffff8a8991c7 R11: fffffbfff1513238 R12: 0000000000000100 R13: ffff8880a14ce058 R14: ffff8880972bee00 R15: ffff8880aa034800 FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000056276e41ac80 CR3: 0000000051031000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_release+0x800/0x800 kernel/locking/lockdep.c:4689 pwq_dec_nr_in_flight+0x310/0x310 kernel/workqueue.c:1198 rwlock_bug.part.0+0x90/0x90 include/linux/sched.h:1329 worker_thread+0x96/0xe20 kernel/workqueue.c:2414 process_one_work+0x16a0/0x16a0 kernel/workqueue.c:2273 kthread+0x388/0x470 kernel/kthread.c:268 kthread_mod_delayed_work+0x1a0/0x1a0 kernel/kthread.c:1090 kthread_mod_delayed_work+0x1a0/0x1a0 kernel/kthread.c:1090 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351