INFO: task syz-executor0:17833 blocked for more than 140 seconds. Not tainted 4.20.0+ #11 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D27160 17833 8362 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x897/0x1e60 kernel/sched/core.c:3472 schedule+0xfe/0x350 kernel/sched/core.c:3516 __rwsem_down_write_failed_common+0xa4d/0x1620 kernel/locking/rwsem-xadd.c:577 rwsem_down_write_failed+0xe/0x10 kernel/locking/rwsem-xadd.c:606 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 __down_write arch/x86/include/asm/rwsem.h:142 [inline] down_write+0xa5/0x130 kernel/locking/rwsem.c:72 inode_lock include/linux/fs.h:757 [inline] do_last fs/namei.c:3321 [inline] path_openat+0x1967/0x5650 fs/namei.c:3534 do_filp_open+0x26f/0x370 fs/namei.c:3564 do_sys_open+0x59a/0x7c0 fs/open.c:1063 ksys_open include/linux/syscalls.h:1298 [inline] __do_sys_creat fs/open.c:1121 [inline] __se_sys_creat fs/open.c:1119 [inline] __x64_sys_creat+0x61/0x80 fs/open.c:1119 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457ec9 Code: Bad RIP value. RSP: 002b:00007fefe4442c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 0000000000457ec9 RDX: 0000000000000000 RSI: 0000000000000044 RDI: 0000000020000a00 RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fefe44436d4 R13: 00000000004be42a R14: 00000000004ce8b8 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1039: #0: 00000000b1c831b7 (rcu_read_lock){....}, at: debug_show_all_locks+0xc6/0x41d kernel/locking/lockdep.c:4389 1 lock held by rsyslogd/8203: #0: 000000007ce86d34 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1b3/0x1f0 fs/file.c:795 2 locks held by getty/8325: #0: 000000005419fff7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000005f1e89a4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8326: #0: 00000000d34adae6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000acf46e9e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8327: #0: 00000000ddab4ed6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000bbfb500d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8328: #0: 00000000cd60dfc5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000f65a0e04 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8329: #0: 0000000091fe072a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000ef2f8cb0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8330: #0: 000000005f098c1b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000009309140f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8331: #0: 00000000844839be (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000030df8ed2 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 4 locks held by syz-executor0/17821: 2 locks held by syz-executor0/17833: #0: 00000000ca3159ac (sb_writers#14){.+.+}, at: sb_start_write include/linux/fs.h:1602 [inline] #0: 00000000ca3159ac (sb_writers#14){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 00000000a5e153ba (&sb->s_type->i_mutex_key#24){++++}, at: inode_lock include/linux/fs.h:757 [inline] #1: 00000000a5e153ba (&sb->s_type->i_mutex_key#24){++++}, at: do_last fs/namei.c:3321 [inline] #1: 00000000a5e153ba (&sb->s_type->i_mutex_key#24){++++}, at: path_openat+0x1967/0x5650 fs/namei.c:3534 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1039 Comm: khungtaskd Not tainted 4.20.0+ #11 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+0x1db/0x2d0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1be/0x236 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0xbbb/0x1170 kernel/hung_task.c:287 kthread+0x357/0x430 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 9046 Comm: kworker/u4:6 Not tainted 4.20.0+ #11 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:__lock_acquire+0x8b7/0x4a30 kernel/locking/lockdep.c:3203 Code: 85 1d 3b 00 00 44 8b 1d 8b f7 f7 08 45 85 db 0f 84 ec b0 00 00 45 31 db 48 ba 00 00 00 00 00 fc ff df 48 03 94 24 90 00 00 00 <31> c0 b9 06 00 00 00 48 89 d7 f3 48 ab 44 89 d8 c7 07 00 00 00 00 RSP: 0018:ffff88804facf510 EFLAGS: 00000082 RAX: 0000000000000003 RBX: 000000007622e6b2 RCX: 0000000000000001 RDX: ffffed1009f59eb6 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88804facf7a0 R08: 0000000000000002 R09: ffff8880933cee70 R10: ffff8880933cee50 R11: 0000000000000001 R12: ffff8880933ce580 R13: 000000005af72ea8 R14: 0000000000000000 R15: 86fa2cd1c5a5384f FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd0e9cfe78 CR3: 000000009a25b000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841 rcu_lock_acquire include/linux/rcupdate.h:223 [inline] rcu_read_lock include/linux/rcupdate.h:607 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:419 [inline] batadv_nc_worker+0x19b/0x920 net/batman-adv/network-coding.c:730 process_one_work+0xd0c/0x1ce0 kernel/workqueue.c:2153 worker_thread+0x143/0x14a0 kernel/workqueue.c:2296 kthread+0x357/0x430 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352