INFO: task syz.0.16:6579 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.16 state:D stack:26168 pid:6579 tgid:6564 ppid:6435 task_flags:0x400040 flags:0x00080002
task:syz.0.16 state:D stack:26168 pid:6579 tgid:6564 ppid:6435 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x16ec/0x5620 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7564
rt_mutex_slowlock_block+0x508/0x680 kernel/locking/rtmutex.c:1662
__rt_mutex_slowlock kernel/locking/rtmutex.c:1739 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1779 [inline]
rt_mutex_slowlock+0x2dc/0x780 kernel/locking/rtmutex.c:1819
__rt_mutex_lock kernel/locking/rtmutex.c:1834 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:535 [inline]
mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:553
fdget_pos+0x252/0x320 fs/file.c:1261
class_fd_pos_constructor include/linux/file.h:85 [inline]
ksys_read+0x79/0x270 fs/read_write.c:708
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f280ae1a079
RSP: 002b:00007f280a05d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f280b046080 RCX: 00007f280ae1a079
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f280aeaca4c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f280b046080 R15: 00007ffc412db678
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8dfc8140 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8dfc8140 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8dfc8140 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5348:
#0: ffff888036c9e0a0 (&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+0x462/0x13a0 drivers/tty/n_tty.c:2211
4 locks held by syz.0.16/6565:
1 lock held by syz.0.16/6579:
#0: ffff888034344d28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1261
5 locks held by syz.1.17/6638:
1 lock held by syz.1.17/6640:
#0: ffff88803d375f28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1261
4 locks held by syz.2.19/6682:
1 lock held by syz.2.19/6684:
#0: ffff8880207a9928 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1261
2 locks held by syz.3.22/6734:
1 lock held by syz.3.22/6736:
#0: ffff88803796bd28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1261
4 locks held by syz.4.23/6787:
1 lock held by syz.4.23/6789:
#0: ffff888027877728 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1261
4 locks held by syz.5.27/6849:
1 lock held by syz.5.27/6851:
#0: ffff88801f2c9328 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1261
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
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+0xfd3/0x1030 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6682 Comm: syz.2.19 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x80 kernel/kcov.c:216
Code: 8b 3d 44 69 c6 0b 48 89 de 5b e9 63 d8 5b 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d 28 29 a6 10 65 8b 35 49 29 a6 10 81 e6 00 00 ff 00 ba
RSP: 0018:ffffc90003817820 EFLAGS: 00000293
RAX: ffffffff8211c14b RBX: ffff88803dbc4100 RCX: ffff888031828000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff52000702ef4 R12: ffff88803dbc4450
R13: ffffc90003817948 R14: 0000200000001000 R15: 0000000000000215
FS: 00007fed08afe6c0(0000) GS:ffff888126276000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 000000003a6dc000 CR4: 00000000003526f0
Call Trace:
arch_static_branch arch/x86/include/asm/jump_label.h:37 [inline]
__mmap_lock_trace_acquire_returned include/linux/mmap_lock.h:41 [inline]
mmap_read_trylock include/linux/mmap_lock.h:612 [inline]
get_mmap_lock_carefully mm/mmap_lock.c:441 [inline]
lock_mm_and_find_vma+0x4b/0x340 mm/mmap_lock.c:501
do_user_addr_fault+0x330/0x1340 arch/x86/mm/fault.c:1357
handle_page_fault arch/x86/mm/fault.c:1474 [inline]
exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0010:rep_movs_alternative+0x4a/0x90 arch/x86/lib/copy_user_64.S:74
Code: cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 db 83 f9 08 73 e8 eb c5 a4 c3 cc cc cc cc 48 8b 06 48 89 07 48 8d 47 08 48 83 e0 f8 48
RSP: 0018:ffffc900038179f8 EFLAGS: 00050206
RAX: ffffffff849ef601 RBX: ffff888028a3c000 RCX: 0000000000000032
RDX: 0000000000000000 RSI: ffff888028a3ce80 RDI: 0000200000001000
RBP: ffffc90003817b78 R08: ffff888028a3ceb1 R09: 1ffff110051479d6
R10: dffffc0000000000 R11: ffffed10051479d7 R12: 1ffff92000702faf
R13: 0000200000000180 R14: ffffc90003817d88 R15: 0000000000000eb2
copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline]
raw_copy_to_user arch/x86/include/asm/uaccess_64.h:147 [inline]
copy_to_user_iter lib/iov_iter.c:25 [inline]
iterate_ubuf include/linux/iov_iter.h:30 [inline]
iterate_and_advance2 include/linux/iov_iter.h:302 [inline]
iterate_and_advance include/linux/iov_iter.h:330 [inline]
_copy_to_iter+0x255/0x17d0 lib/iov_iter.c:197
copy_to_iter include/linux/uio.h:220 [inline]
seq_read_iter+0xbf6/0xe20 fs/seq_file.c:282
proc_reg_read_iter+0x1bf/0x290 fs/proc/inode.c:299
new_sync_read fs/read_write.c:493 [inline]
vfs_read+0x58b/0xa80 fs/read_write.c:574
ksys_read+0x156/0x270 fs/read_write.c:717
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fed0989a079
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fed08afe028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fed09ac5fa0 RCX: 00007fed0989a079
RDX: 0000000000002024 RSI: 0000200000000180 RDI: 0000000000000005
RBP: 00007fed0992ca4c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fed09ac5fa0 R15: 00007fffd8327588