INFO: task syz-executor0:5384 blocked for more than 140 seconds. Not tainted 4.19.0+ #76 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D18984 5384 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x86c/0x1ed0 kernel/sched/core.c:3473 schedule+0xfe/0x460 kernel/sched/core.c:3517 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:269 [inline] rwsem_down_read_failed+0x362/0x610 kernel/locking/rwsem-xadd.c:286 call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94 __down_read arch/x86/include/asm/rwsem.h:83 [inline] down_read+0xbe/0x1d0 kernel/locking/rwsem.c:26 inode_lock_shared include/linux/fs.h:748 [inline] lookup_slow+0x49/0x80 fs/namei.c:1687 walk_component+0x92b/0x25c0 fs/namei.c:1810 link_path_walk.part.40+0xa61/0x1530 fs/namei.c:2141 link_path_walk fs/namei.c:2072 [inline] path_openat+0x270/0x5160 fs/namei.c:3533 do_filp_open+0x255/0x380 fs/namei.c:3564 do_sys_open+0x568/0x700 fs/open.c:1063 __do_sys_open fs/open.c:1081 [inline] __se_sys_open fs/open.c:1076 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1076 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455570 Code: Bad RIP value. RSP: 002b:00007fff5ffe71c0 EFLAGS: 00000206 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000455570 RDX: 0000000000000000 RSI: 0000000000090800 RDI: 00000000004bc2ae RBP: 00000000000007cb R08: 0000000000000001 R09: 0000000001735940 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000004 R13: 000000000008f873 R14: 0000000000000326 R15: 0000000000000000 INFO: task syz-executor0:22092 blocked for more than 140 seconds. Not tainted 4.19.0+ #76 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D24824 22092 5384 0x00000004 Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x86c/0x1ed0 kernel/sched/core.c:3473 schedule+0xfe/0x460 kernel/sched/core.c:3517 __rwsem_down_write_failed_common+0xbb9/0x1670 kernel/locking/rwsem-xadd.c:566 rwsem_down_write_failed+0xe/0x10 kernel/locking/rwsem-xadd.c:595 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:738 [inline] do_last fs/namei.c:3321 [inline] path_openat+0x15c7/0x5160 fs/namei.c:3534 do_filp_open+0x255/0x380 fs/namei.c:3564 do_sys_open+0x568/0x700 fs/open.c:1063 __do_sys_openat fs/open.c:1090 [inline] __se_sys_openat fs/open.c:1084 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1084 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457569 Code: Bad RIP value. RSP: 002b:00007fd8a2b26c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457569 RDX: 0000000000002761 RSI: 0000000020000480 RDI: ffffffffffffffff RBP: 000000000072bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd8a2b276d4 R13: 00000000004c2b12 R14: 00000000004d4140 R15: 00000000ffffffff Showing all locks held in the system: 4 locks held by kworker/u4:0/7: 1 lock held by khungtaskd/983: #0: 00000000fe7623b0 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4435 1 lock held by rsyslogd/5255: #0: 00000000943f47c0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/5345: #0: 0000000061a37fc2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000007c3ab737 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5346: #0: 000000003819dd91 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000055458b1f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5347: #0: 00000000a1ff814e (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000002691fdcc (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5348: #0: 00000000182b03fc (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000006e84cfa1 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5349: #0: 0000000029109a34 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000000c09030b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5350: #0: 00000000496df92d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000320d61bd (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5351: #0: 00000000c07c227c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000007f673b74 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 1 lock held by syz-executor0/5384: #0: 0000000053161299 (&sb->s_type->i_mutex_key#25){++++}, at: inode_lock_shared include/linux/fs.h:748 [inline] #0: 0000000053161299 (&sb->s_type->i_mutex_key#25){++++}, at: lookup_slow+0x49/0x80 fs/namei.c:1687 2 locks held by syz-executor4/21530: #0: 000000008650f871 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000cdf1be13 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 3 locks held by syz-executor0/22085: 2 locks held by syz-executor0/22092: #0: 00000000a87732a1 (sb_writers#16){.+.+}, at: sb_start_write include/linux/fs.h:1566 [inline] #0: 00000000a87732a1 (sb_writers#16){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 0000000053161299 (&sb->s_type->i_mutex_key#25){++++}, at: inode_lock include/linux/fs.h:738 [inline] #1: 0000000053161299 (&sb->s_type->i_mutex_key#25){++++}, at: do_last fs/namei.c:3321 [inline] #1: 0000000053161299 (&sb->s_type->i_mutex_key#25){++++}, at: path_openat+0x15c7/0x5160 fs/namei.c:3534 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 983 Comm: khungtaskd Not tainted 4.19.0+ #76 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+0x1c4/0x2b6 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.3+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x1ed 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:144 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline] watchdog+0xb3e/0x1050 kernel/hung_task.c:265 kthread+0x35a/0x420 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413 Sending NMI from CPU 0 to CPUs 1: INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 2.199 msecs NMI backtrace for cpu 1 CPU: 1 PID: 7 Comm: kworker/u4:0 Not tainted 4.19.0+ #76 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-7:0) RIP: 0010:check_preemption_disabled+0x10/0x280 lib/smp_processor_id.c:12 Code: f3 ff ff e8 72 92 34 fe e9 5d ec ff ff e8 68 92 34 fe e9 26 ec ff ff 90 90 90 55 48 89 e5 41 57 41 56 49 89 f6 41 55 49 89 fd <41> 54 53 48 83 ec 08 e8 a4 0d f1 fd 65 44 8b 25 0c db 73 7c 65 8b RSP: 0018:ffff8801d9ac61b8 EFLAGS: 00000093 RAX: ffff8801d9ab81c0 RBX: ffffffff88158660 RCX: ffffffff81df3405 RDX: 0000000000000000 RSI: ffffffff88158660 RDI: ffffffff88409b80 RBP: ffff8801d9ac61d0 R08: ffff8801d9ab81c0 R09: fffff94000c535ae R10: fffff94000c535ae R11: ffffea000629ad77 R12: 0000000000000003 R13: ffffffff88409b80 R14: ffffffff88158660 R15: 000000000000042b FS: 0000000000000000(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000455546 CR3: 00000001bc720000 CR4: 00000000001426e0 Call Trace: __this_cpu_preempt_check+0x1c/0x20 lib/smp_processor_id.c:62 lookup_bh_lru fs/buffer.c:1261 [inline] __find_get_block+0x183/0xf20 fs/buffer.c:1290 __getblk_slow fs/buffer.c:1039 [inline] __getblk_gfp+0x2b3/0xd50 fs/buffer.c:1320 __bread_gfp+0x2d/0x300 fs/buffer.c:1354 sb_bread include/linux/buffer_head.h:307 [inline] __fat_write_inode+0x347/0xb60 fs/fat/inode.c:859 fat_write_inode+0x97/0x180 fs/fat/inode.c:908 write_inode fs/fs-writeback.c:1183 [inline] __writeback_single_inode+0xf1f/0x1620 fs/fs-writeback.c:1382 writeback_sb_inodes+0x71f/0x11d0 fs/fs-writeback.c:1587 __writeback_inodes_wb+0x1b9/0x340 fs/fs-writeback.c:1656 wb_writeback+0xa73/0xfc0 fs/fs-writeback.c:1765 wb_check_old_data_flush fs/fs-writeback.c:1867 [inline] wb_do_writeback fs/fs-writeback.c:1920 [inline] wb_workfn+0x1008/0x1790 fs/fs-writeback.c:1949 process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153 worker_thread+0x17f/0x1390 kernel/workqueue.c:2296 kthread+0x35a/0x420 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413