INFO: task syz-fuzzer:7988 blocked for more than 140 seconds. Not tainted 4.19.61 #35 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-fuzzer D25392 7988 7972 0x00000000 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x866/0x1dc0 kernel/sched/core.c:3474 schedule+0x92/0x1c0 kernel/sched/core.c:3518 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x21b/0x3c0 kernel/locking/rwsem-xadd.c:309 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+0x49/0xb0 kernel/locking/rwsem.c:26 __do_page_fault+0xb1a/0xe90 arch/x86/mm/fault.c:1329 do_page_fault+0x71/0x57d arch/x86/mm/fault.c:1468 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1203 RIP: 0033:0x45a2a3 Code: Bad RIP value. RSP: 002b:000000c4201a7738 EFLAGS: 00010283 RAX: 0000000000000000 RBX: 0000000000000580 RCX: 000000c4272d8100 RDX: 000000c420056400 RSI: 000000000000051c RDI: 000000c4272d8100 RBP: 000000c4201a77d0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffffffffffffffff R13: 0000000000000007 R14: 0000000000000006 R15: 000000000000000b Showing all locks held in the system: 1 lock held by khungtaskd/1036: #0: 00000000da02195a (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:4435 3 locks held by rs:main Q:Reg/7826: #0: 000000001563e95b (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:767 #1: 00000000b02c645d (sb_writers#4){.+.+}, at: file_start_write include/linux/fs.h:2773 [inline] #1: 00000000b02c645d (sb_writers#4){.+.+}, at: vfs_write+0x429/0x560 fs/read_write.c:548 #2: 000000002d0b3376 (&sb->s_type->i_mutex_key#9){++++}, at: inode_trylock include/linux/fs.h:767 [inline] #2: 000000002d0b3376 (&sb->s_type->i_mutex_key#9){++++}, at: ext4_file_write_iter+0x23f/0x1060 fs/ext4/file.c:232 1 lock held by rsyslogd/7829: #0: 00000000ad37a4ee (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:767 2 locks held by getty/7950: #0: 00000000c1316f1c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363 #1: 00000000529c23f6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7951: #0: 0000000032c0924d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363 #1: 000000008f32ed13 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7952: #0: 00000000e24ee402 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363 #1: 00000000dfa79c93 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7953: #0: 0000000038bf631c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363 #1: 00000000f313c78c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7954: #0: 0000000008dcfe7d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363 #1: 00000000e745afda (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7955: #0: 000000009f25066b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363 #1: 00000000755a6877 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7956: #0: 00000000e65490c2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363 #1: 000000002c6d46cc (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 1 lock held by syz-fuzzer/7975: #0: 000000003fb1cd04 (&mm->mmap_sem){++++}, at: __do_sys_madvise mm/madvise.c:837 [inline] #0: 000000003fb1cd04 (&mm->mmap_sem){++++}, at: __se_sys_madvise mm/madvise.c:801 [inline] #0: 000000003fb1cd04 (&mm->mmap_sem){++++}, at: __x64_sys_madvise+0x2b3/0x14f0 mm/madvise.c:801 1 lock held by syz-fuzzer/7978: #0: 000000003fb1cd04 (&mm->mmap_sem){++++}, at: __do_page_fault+0x3c9/0xe90 arch/x86/mm/fault.c:1322 1 lock held by syz-fuzzer/7988: #0: 000000003fb1cd04 (&mm->mmap_sem){++++}, at: __do_page_fault+0xb1a/0xe90 arch/x86/mm/fault.c:1329 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1036 Comm: khungtaskd Not tainted 4.19.61 #35 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+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b0/0x1f8 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+0x9df/0xee0 kernel/hung_task.c:287 kthread+0x354/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3602 Comm: udevd Not tainted 4.19.61 #35 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:788 [inline] RIP: 0010:lock_is_held_type+0x17e/0x210 kernel/locking/lockdep.c:3940 Code: 00 00 00 fc ff df 41 c7 85 7c 08 00 00 00 00 00 00 48 c1 e8 03 80 3c 10 00 75 63 48 83 3d 41 7c 20 07 00 74 30 48 89 df 57 9d <0f> 1f 44 00 00 48 83 c4 08 44 89 e0 5b 41 5c 41 5d 5d c3 48 83 c4 RSP: 0018:ffff888097d0fae0 EFLAGS: 00000282 RAX: 1ffffffff10e4879 RBX: 0000000000000282 RCX: ffff888097d04a40 RDX: dffffc0000000000 RSI: ffff88809603fa60 RDI: 0000000000000282 RBP: ffff888097d0fb00 R08: ffff888097d041c0 R09: ffff888097d04a60 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffff888097d041c0 R14: ffff888097d0fdc0 R15: ffff888097d0fc60 FS: 00007f697780a7a0(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f994c2d3108 CR3: 0000000096a45000 CR4: 00000000001406e0 Call Trace: lock_is_held include/linux/lockdep.h:344 [inline] ep_wakeup_source fs/eventpoll.c:630 [inline] ep_send_events_proc+0x3e9/0xc10 fs/eventpoll.c:1654 ep_scan_ready_list+0x305/0xb20 fs/eventpoll.c:708 ep_send_events fs/eventpoll.c:1713 [inline] ep_poll+0x3b4/0xd10 fs/eventpoll.c:1840 do_epoll_wait+0x1b3/0x200 fs/eventpoll.c:2198 __do_sys_epoll_wait fs/eventpoll.c:2208 [inline] __se_sys_epoll_wait fs/eventpoll.c:2205 [inline] __x64_sys_epoll_wait+0x97/0xf0 fs/eventpoll.c:2205 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f6976f1e943 Code: 00 31 d2 48 29 c2 64 89 11 48 83 c8 ff eb ea 90 90 90 90 90 90 90 90 83 3d b5 dc 2a 00 00 75 13 49 89 ca b8 e8 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 3b c4 00 00 48 89 04 24 RSP: 002b:00007ffd4bdb1518 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8 RAX: ffffffffffffffda RBX: 0000000000000bb8 RCX: 00007f6976f1e943 RDX: 0000000000000008 RSI: 00007ffd4bdb1610 RDI: 000000000000000a RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000bb8 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000000 R14: 000000000187bd00 R15: 0000000001861030