INFO: task syz-executor0:6196 blocked for more than 140 seconds. Not tainted 4.20.0-rc3+ #126 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D18568 6196 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x8cf/0x21d0 kernel/sched/core.c:3472 schedule+0xfe/0x460 kernel/sched/core.c:3516 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3574 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0xaff/0x16f0 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 vfat_lookup+0xf1/0x640 fs/fat/namei_vfat.c:709 __lookup_slow+0x2b5/0x540 fs/namei.c:1671 lookup_slow+0x57/0x80 fs/namei.c:1688 walk_component+0x92b/0x2590 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+0x270/0x5150 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:00007ffd58edb3d0 EFLAGS: 00000202 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000455570 RDX: 0000000000000000 RSI: 0000000000090800 RDI: 00000000004bc2ae RBP: 0000000000000818 R08: 0000000000000001 R09: 0000000000a76940 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000018 R13: 000000000007332c R14: 0000000000000277 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/1018: #0: 000000005b974042 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4379 3 locks held by rs:main Q:Reg/6030: #0: 00000000d7372fa9 (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1126 [inline] #0: 00000000d7372fa9 (&rq->lock){-.-.}, at: __schedule+0x236/0x21d0 kernel/sched/core.c:3410 #1: 000000005b974042 (rcu_read_lock){....}, at: file_start_write include/linux/fs.h:2810 [inline] #1: 000000005b974042 (rcu_read_lock){....}, at: vfs_write+0x42a/0x560 fs/read_write.c:548 #2: 000000005b974042 (rcu_read_lock){....}, at: inode_trylock include/linux/fs.h:777 [inline] #2: 000000005b974042 (rcu_read_lock){....}, at: ext4_file_write_iter+0x2a1/0x1420 fs/ext4/file.c:232 1 lock held by rsyslogd/6032: #0: 00000000d24628db (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/6154: #0: 0000000099535500 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000003054e87f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6155: #0: 00000000a9a13b67 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000595b6daa (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6156: #0: 0000000045016cf5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000c77aac55 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6157: #0: 0000000040cd7920 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000001deab59a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6158: #0: 0000000095505b83 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000ecbd1b3c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6159: #0: 00000000d8e6fab4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000000ad0042e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6160: #0: 00000000e23be9d1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000122d289a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by syz-executor0/6196: #0: 0000000079890120 (&sb->s_type->i_mutex_key#21){++++}, at: inode_lock_shared include/linux/fs.h:767 [inline] #0: 0000000079890120 (&sb->s_type->i_mutex_key#21){++++}, at: lookup_slow+0x49/0x80 fs/namei.c:1687 #1: 00000000cf38da74 (&sbi->s_lock){+.+.}, at: vfat_lookup+0xf1/0x640 fs/fat/namei_vfat.c:709 3 locks held by syz-executor0/18964: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1018 Comm: khungtaskd Not tainted 4.20.0-rc3+ #126 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+0x244/0x39d lib/dump_stack.c:113 nmi_cpu_backtrace.cold.2+0x5c/0xa1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1e8/0x22a 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:205 [inline] watchdog+0xb51/0x1060 kernel/hung_task.c:289 kthread+0x35a/0x440 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: 18964 Comm: syz-executor0 Not tainted 4.20.0-rc3+ #126 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.831 msecs Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:rcu_lockdep_current_cpu_online+0x10e/0x210 kernel/rcu/tree.c:955 Code: 2a 00 0f 85 d6 00 00 00 4c 03 24 c5 20 30 27 89 48 b8 00 00 00 00 00 fc ff df 49 8d 7c 24 18 48 89 fa 48 c1 ea 03 80 3c 02 00 <0f> 85 c6 00 00 00 49 8d 7c 24 20 4d 8b 6c 24 18 48 b8 00 00 00 00 RSP: 0018:ffff8881aed063c0 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 1ffff11035da0c79 RCX: ffffc9000685f000 RDX: 1ffff1103b5c5b53 RSI: ffffffff83939b08 RDI: ffff8881dae2da98 RBP: ffff8881aed06450 R08: ffff8881bde10600 R09: ffffed103b5c5b67 R10: ffffed103b5c5b67 R11: ffff8881dae2db3b R12: ffff8881dae2da80 R13: dffffc0000000000 R14: ffff8881aed06428 R15: ffff8881aed06530 FS: 00007f0ae015d700(0000) GS:ffff8881dae00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 00000001b38dc000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock_held+0x90/0xc0 kernel/rcu/update.c:279 xa_entry include/linux/xarray.h:709 [inline] xas_descend+0x413/0x510 lib/xarray.c:198 xas_load+0x145/0x1e0 lib/xarray.c:234 find_get_entry+0x3ca/0x1120 mm/filemap.c:1415 pagecache_get_page+0x12f/0xf00 mm/filemap.c:1518 find_get_page_flags include/linux/pagemap.h:278 [inline] __find_get_block_slow fs/buffer.c:205 [inline] __find_get_block+0x63a/0xf20 fs/buffer.c:1294 __getblk_slow fs/buffer.c:1039 [inline] __getblk_gfp+0x2b3/0xd50 fs/buffer.c:1320 __bread_gfp+0x2d/0x310 fs/buffer.c:1354 sb_bread include/linux/buffer_head.h:307 [inline] fat__get_entry+0x5a6/0xa40 fs/fat/dir.c:101 fat_get_entry fs/fat/dir.c:129 [inline] fat_search_long+0x33b/0x1570 fs/fat/dir.c:479 vfat_find+0x16d/0x1a0 fs/fat/namei_vfat.c:697 vfat_lookup+0x107/0x640 fs/fat/namei_vfat.c:711 lookup_open+0x72e/0x1b90 fs/namei.c:3213 do_last fs/namei.c:3324 [inline] path_openat+0x2464/0x5150 fs/namei.c:3534 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: 0033:0x4111a1 Code: 75 14 b8 02 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 b4 17 00 00 c3 48 83 ec 08 e8 8a fa ff ff 48 89 04 24 b8 02 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 d3 fa ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007f0ae015c7a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 00000000004111a1 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f0ae015c850 RBP: 000000000072c220 R08: 000000000000000f R09: 0000000000000000 R10: 00007f0ae015d9d0 R11: 0000000000000293 R12: 00007f0ae015d6d4 R13: 00000000004c55cb R14: 00000000004d9478 R15: 00000000ffffffff