INFO: task syz-executor.1:10277 blocked for more than 143 seconds. Not tainted 5.6.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D23984 10277 1 0x00004004 Call Trace: context_switch kernel/sched/core.c:3386 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4082 schedule+0xdc/0x2b0 kernel/sched/core.c:4156 rwsem_down_write_slowpath+0x706/0xf90 kernel/locking/rwsem.c:1238 __down_write kernel/locking/rwsem.c:1392 [inline] down_write+0x13c/0x150 kernel/locking/rwsem.c:1535 inode_lock include/linux/fs.h:791 [inline] vfs_unlink+0xd5/0x620 fs/namei.c:4064 do_unlinkat+0x3f7/0x6d0 fs/namei.c:4137 __do_sys_unlink fs/namei.c:4184 [inline] __se_sys_unlink fs/namei.c:4182 [inline] __x64_sys_unlink+0x42/0x50 fs/namei.c:4182 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c417 Code: 00 66 90 b8 58 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 4d b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 57 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 2d b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffe9dc208f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000045c417 RDX: 00007ffe9dc20910 RSI: 00007ffe9dc20910 RDI: 00007ffe9dc209a0 RBP: 0000000000000458 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000003 R11: 0000000000000246 R12: 00007ffe9dc21a30 R13: 0000000001be2940 R14: 0000000000000000 R15: 00007ffe9dc21a30 INFO: task syz-executor.2:10278 blocked for more than 143 seconds. Not tainted 5.6.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D23984 10278 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:3386 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4082 schedule+0xdc/0x2b0 kernel/sched/core.c:4156 rwsem_down_write_slowpath+0x706/0xf90 kernel/locking/rwsem.c:1238 __down_write kernel/locking/rwsem.c:1392 [inline] down_write+0x13c/0x150 kernel/locking/rwsem.c:1535 inode_lock include/linux/fs.h:791 [inline] vfs_unlink+0xd5/0x620 fs/namei.c:4064 do_unlinkat+0x3f7/0x6d0 fs/namei.c:4137 __do_sys_unlink fs/namei.c:4184 [inline] __se_sys_unlink fs/namei.c:4182 [inline] __x64_sys_unlink+0x42/0x50 fs/namei.c:4182 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c417 Code: 00 66 90 b8 58 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 4d b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 57 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 2d b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffc041b9ea8 EFLAGS: 00000246 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000045c417 RDX: 00007ffc041b9ec0 RSI: 00007ffc041b9ec0 RDI: 00007ffc041b9f50 RBP: 000000000000043e R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000003 R11: 0000000000000246 R12: 00007ffc041bafe0 R13: 00000000015d5940 R14: 0000000000000000 R15: 00007ffc041bafe0 Showing all locks held in the system: 2 locks held by kworker/u4:5/353: 1 lock held by khungtaskd/1131: #0: ffffffff89bac240 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5333 1 lock held by rsyslogd/9630: #0: ffff8880a8ed2de0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:821 2 locks held by getty/9720: #0: ffff8880993b2090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900067232e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9721: #0: ffff888099d9d090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900066fb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9722: #0: ffff88808d754090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900067332e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9723: #0: ffff888099c64090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900067142e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9724: #0: ffff888099bc0090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900066ab2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9725: #0: ffff88808ed75090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900067432e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9726: #0: ffff888091e35090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000667b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 3 locks held by syz-executor.1/10277: #0: ffff8880991fe428 (sb_writers#3){.+.+}, at: sb_start_write include/linux/fs.h:1649 [inline] #0: ffff8880991fe428 (sb_writers#3){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:354 #1: ffff8880960e88c8 (&type->i_mutex_dir_key#3/1){+.+.}, at: inode_lock_nested include/linux/fs.h:826 [inline] #1: ffff8880960e88c8 (&type->i_mutex_dir_key#3/1){+.+.}, at: do_unlinkat+0x29f/0x6d0 fs/namei.c:4123 #2: ffff8880309eb708 (&sb->s_type->i_mutex_key#11){+.+.}, at: inode_lock include/linux/fs.h:791 [inline] #2: ffff8880309eb708 (&sb->s_type->i_mutex_key#11){+.+.}, at: vfs_unlink+0xd5/0x620 fs/namei.c:4064 3 locks held by syz-executor.2/10278: #0: ffff8880991fe428 (sb_writers#3){.+.+}, at: sb_start_write include/linux/fs.h:1649 [inline] #0: ffff8880991fe428 (sb_writers#3){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:354 #1: ffff8880919f5908 (&type->i_mutex_dir_key#3/1){+.+.}, at: inode_lock_nested include/linux/fs.h:826 [inline] #1: ffff8880919f5908 (&type->i_mutex_dir_key#3/1){+.+.}, at: do_unlinkat+0x29f/0x6d0 fs/namei.c:4123 #2: ffff88808dd1e9c8 (&sb->s_type->i_mutex_key#11){+.+.}, at: inode_lock include/linux/fs.h:791 [inline] #2: ffff88808dd1e9c8 (&sb->s_type->i_mutex_key#11){+.+.}, at: vfs_unlink+0xd5/0x620 fs/namei.c:4064 2 locks held by syz-executor.2/20654: #0: ffff8880991fe428 (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2903 [inline] #0: ffff8880991fe428 (sb_writers#3){.+.+}, at: vfs_write+0x485/0x5d0 fs/read_write.c:557 #1: ffff88808dd1e9c8 (&sb->s_type->i_mutex_key#11){+.+.}, at: inode_lock include/linux/fs.h:791 [inline] #1: ffff88808dd1e9c8 (&sb->s_type->i_mutex_key#11){+.+.}, at: ext4_buffered_write_iter+0xba/0x460 fs/ext4/file.c:264 2 locks held by syz-executor.1/20676: #0: ffff8880991fe428 (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2903 [inline] #0: ffff8880991fe428 (sb_writers#3){.+.+}, at: vfs_write+0x485/0x5d0 fs/read_write.c:557 #1: ffff8880309eb708 (&sb->s_type->i_mutex_key#11){+.+.}, at: inode_lock include/linux/fs.h:791 [inline] #1: ffff8880309eb708 (&sb->s_type->i_mutex_key#11){+.+.}, at: ext4_buffered_write_iter+0xba/0x460 fs/ext4/file.c:264 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1131 Comm: khungtaskd Not tainted 5.6.0-rc1-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+0x197/0x210 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b 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+0xb11/0x10c0 kernel/hung_task.c:289 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60