INFO: task syz.5.984:11061 blocked for mo[ 941.135603][ T38] INFO: task syz.5.984:11061 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.5.984 state:D stack:28424 pid:11061 tgid:11057 ppid:9552 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x16dc/0x5500 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7607 rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline] __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline] rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline] __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline] mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578 write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 nfsctl_transaction_write+0x112/0x160 fs/nfsd/nfsctl.c:112 vfs_write+0x29f/0xbb0 fs/read_write.c:685 ksys_write+0x156/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbc557ede99 RSP: 002b:00007fbc53a25028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fbc55a76090 RCX: 00007fbc557ede99 RDX: 0000000000000002 RSI: 00002000000002c0 RDI: 0000000000000003 RBP: 00007fbc55883eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fbc55a76128 R14: 00007fbc55a76090 R15: 00007ffe50d1bd08 INFO: task syz.8.1012:11147 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.8.1012 state:D stack:28424 pid:11147 tgid:11145 ppid:9996 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x16dc/0x5500 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7607 rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline] __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline] rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline] __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline] mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578 write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 nfsctl_transaction_write+0x112/0x160 fs/nfsd/nfsctl.c:112 vfs_write+0x29f/0xbb0 fs/read_write.c:685 ksys_write+0x156/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fef6066de99 RSP: 002b:00007fef5e8c6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fef608f5fa0 RCX: 00007fef6066de99 RDX: 0000000000000009 RSI: 0000200000000300 RDI: 0000000000000003 RBP: 00007fef60703eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fef608f6038 R14: 00007fef608f5fa0 R15: 00007ffe13ee2808 INFO: task syz.8.1012:11149 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.8.1012 state:D stack:28424 pid:11149 tgid:11145 ppid:9996 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x16dc/0x5500 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7607 rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline] __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline] rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline] __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline] mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578 write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 nfsctl_transaction_write+0x112/0x160 fs/nfsd/nfsctl.c:112 vfs_write+0x29f/0xbb0 fs/read_write.c:685 ksys_write+0x156/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fef6066de99 RSP: 002b:00007fef5e8a5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fef608f6090 RCX: 00007fef6066de99 RDX: 0000000000000002 RSI: 0000200000000380 RDI: 0000000000000004 RBP: 00007fef60703eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fef608f6128 R14: 00007fef608f6090 R15: 00007ffe13ee2808 INFO: task syz.7.1013:11152 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.7.1013 state:D stack:28424 pid:11152 tgid:11151 ppid:10012 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x16dc/0x5500 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7607 rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline] __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline] rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline] __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline] mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578 write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:701 nfsctl_transaction_write+0x112/0x160 fs/nfsd/nfsctl.c:112 vfs_write+0x29f/0xbb0 fs/read_write.c:685 ksys_write+0x156/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc2ef30de99 RSP: 002b:00007fc2ed566028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fc2ef595fa0 RCX: 00007fc2ef30de99 RDX: 0000000000000007 RSI: 0000200000000340 RDI: 0000000000000003 RBP: 00007fc2ef3a3eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc2ef596038 R14: 00007fc2ef595fa0 R15: 00007ffe56e3b2b8 Showing all locks held in the system: 1 lock held by khungtaskd/38: #0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:9/997: 2 locks held by getty/5352: #0: ffff888035b1e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003cbe2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211 7 locks held by kworker/u8:18/5901: 6 locks held by kworker/u8:19/6165: 3 locks held by syz.5.984/11058: #0: ffff88805bdcdd28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888036f2c500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888036f2c500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 3 locks held by syz.5.984/11061: #0: ffff88805d166728 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888036f2c500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888036f2c500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz.8.1012/11147: #0: ffff88803301f328 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888036f24500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888036f24500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 3 locks held by syz.8.1012/11149: #0: ffff8880367e9b28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888036f24500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888036f24500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz.7.1013/11152: #0: ffff88803573e528 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88803cf90500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88803cf90500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:701 3 locks held by syz.9.1039/11236: #0: ffff88803f73d928 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888069698500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888069698500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:701 3 locks held by syz.9.1039/11237: #0: ffff88803f73c728 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888069698500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888069698500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 3 locks held by syz.9.1039/11238: #0: ffff888029562528 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888069698500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888069698500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz.9.1039/11241: #0: ffff88803f73d328 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888069698500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888069698500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz.1.1048/11284: #0: ffff88805420a128 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888068b42500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888068b42500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 3 locks held by syz.1.1048/11285: #0: ffff88805420a728 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888068b42500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888068b42500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz.3.1151/11708: #0: ffff888033d16d28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88803ec48500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88803ec48500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 3 locks held by syz.4.1165/11756: #0: ffff888034a38b28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888084d82500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888084d82500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:701 3 locks held by syz.4.1165/11759: #0: ffff88802b136f28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888084d82500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888084d82500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 3 locks held by syz.4.1165/11763: #0: ffff88802b137728 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888084d82500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888084d82500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz.0.1172/11787: #0: ffff888034a36d28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88803b070500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88803b070500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:701 3 locks held by syz.0.1172/11788: #0: ffff8880370ea328 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88803b070500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88803b070500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 3 locks held by syz.0.1172/11789: #0: ffff88803d6d3328 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88803b070500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88803b070500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz.2.1181/11815: #0: ffff8880288e3928 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88806a22a500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88806a22a500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 3 locks held by syz.6.1195/11846: #0: ffff888035740d28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff8880368f4500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff8880368f4500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:701 3 locks held by syz.6.1195/11847: #0: ffff888035740b28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff8880368f4500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff8880368f4500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 3 locks held by syz.6.1195/11848: #0: ffff88803546b928 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff8880368f4500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff8880368f4500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz.6.1195/11849: #0: ffff888035741528 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff8880368f4500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff8880368f4500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 3 locks held by syz.6.1195/11850: #0: ffff88803546b328 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff8880368f4500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff8880368f4500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 6 locks held by kworker/u8:2/11944: 3 locks held by syz.8.1263/12262: #0: ffff88803754b928 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888028328500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888028328500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:701 3 locks held by syz.8.1263/12263: #0: ffff8880288e3528 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888028328500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888028328500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 3 locks held by syz.8.1263/12264: #0: ffff888034a24928 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888028328500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888028328500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz.7.1343/12467: #0: ffff888082d63d28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888022712500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888022712500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 3 locks held by syz.9.1409/12640: #0: ffff88803bd3af28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888062b66500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888062b66500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 3 locks held by syz.9.1409/12645: #0: ffff8880591b7128 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888062b66500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888062b66500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz.1.1512/12984: #0: ffff8880591b6b28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff888020b0c500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff888020b0c500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz.5.1557/13143: #0: ffff88803634e328 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88805f738500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88805f738500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:701 3 locks held by syz.5.1557/13146: #0: ffff888033191b28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88805f738500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88805f738500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 3 locks held by syz.5.1557/13150: #0: ffff888033f0c128 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88805f738500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88805f738500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz-executor/13260: 3 locks held by syz.0.1596/13278: #0: ffff88802554e328 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88803ac3e500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88803ac3e500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:701 3 locks held by syz.0.1596/13280: #0: ffff888082d63528 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88803ac3e500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88803ac3e500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 3 locks held by syz.0.1596/13285: #0: ffff88803277e928 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88803ac3e500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88803ac3e500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz.3.1598/13290: #0: ffff88802b136328 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88803775e500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88803775e500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:701 3 locks held by syz.3.1598/13292: #0: ffff88802b136728 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88803775e500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88803775e500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:860 3 locks held by syz.3.1598/13293: #0: ffff88802fdc8728 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88803775e500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88803775e500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz.3.1598/13294: #0: ffff88802b136b28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88803775e500 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88803775e500 (sb_writers#17){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffffffff8e4e9538 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3a0/0x5a0 fs/nfsd/nfsctl.c:432 3 locks held by syz.4.1600/13299: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122 nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline] watchdog+0xfd7/0x1030 kernel/hung_task.c:561 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 17 Comm: pr/legacy Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401 Code: e8 ae bd 6f fc 44 89 f9 d3 e3 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 ff 2f d9 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07 RSP: 0000:ffffc90000167a28 EFLAGS: 00000202 RAX: 1ffffffff33c9500 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000 RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffffff85560cf0 R12: dffffc0000000000 R13: 0000000000000000 R14: ffffffff99e4ad40 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125c41000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2f623ffc CR3: 00000000202d0000 CR4: 00000000003526f0 Call Trace: serial_in drivers/tty/serial/8250/8250.h:128 [inline] serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline] wait_for_lsr+0x190/0x300 drivers/tty/serial/8250/8250_port.c:1982 serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3235 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3300 [inline] serial8250_console_write+0x113a/0x1b40 drivers/tty/serial/8250/8250_port.c:3385 console_emit_next_record kernel/printk/printk.c:3163 [inline] console_flush_one_record+0x642/0xb50 kernel/printk/printk.c:3269 legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3712 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245