syzbot

INFO: task syz.3.36:6180 blocked for more than 143 seconds.
      Not tainted syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.36        state:D stack:24768 pid:6180  tgid:6180  ppid:5966   task_flags:0x40004c flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5352 [inline]
 __schedule+0x1665/0x5590 kernel/sched/core.c:6964
 __schedule_loop kernel/sched/core.c:7047 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7062
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7119
 rwsem_down_read_slowpath+0x6d9/0x940 kernel/locking/rwsem.c:1114
 __down_read_common kernel/locking/rwsem.c:1291 [inline]
 __down_read kernel/locking/rwsem.c:1304 [inline]
 down_read+0x99/0x2e0 kernel/locking/rwsem.c:1570
 mmap_read_lock include/linux/mmap_lock.h:592 [inline]
 exit_mm+0x73/0x250 kernel/exit.c:557
 do_exit+0x8b9/0x2490 kernel/exit.c:962
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1116
 __do_sys_exit_group kernel/exit.c:1127 [inline]
 __se_sys_exit_group kernel/exit.c:1125 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1125
 x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f959eb9c799
RSP: 002b:00007fffe5792a88 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f959eb9c799
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fffe5792aec R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000006 R11: 0000000000000246 R12: 0000000000000004
R13: 00000000000927c0 R14: 0000000000019f16 R15: 00007fffe5792b40
 </TASK>
INFO: task syz.3.36:6181 blocked for more than 144 seconds.
      Not tainted syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.36        state:D stack:26424 pid:6181  tgid:6180  ppid:5966   task_flags:0x40044c flags:0x00080001
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5352 [inline]
 __schedule+0x1665/0x5590 kernel/sched/core.c:6964
 __schedule_loop kernel/sched/core.c:7047 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7062
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7119
 rwsem_down_read_slowpath+0x6d9/0x940 kernel/locking/rwsem.c:1114
 __down_read_common kernel/locking/rwsem.c:1291 [inline]
 __down_read kernel/locking/rwsem.c:1304 [inline]
 down_read+0x99/0x2e0 kernel/locking/rwsem.c:1570
 mmap_read_lock include/linux/mmap_lock.h:592 [inline]
 exit_mm+0x73/0x250 kernel/exit.c:557
 do_exit+0x8b9/0x2490 kernel/exit.c:962
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1116
 get_signal+0x1284/0x1330 kernel/signal.c:3035
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:269 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f959eb9c799
RSP: 002b:00007f959f9e0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: 0000000000000116 RBX: 00007f959ee15fa0 RCX: 00007f959eb9c799
RDX: 0000000000000318 RSI: 00002000000bd000 RDI: 0000000000000004
RBP: 00007f959ec32c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f959ee16038 R14: 00007f959ee15fa0 R15: 00007fffe5792748
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8e75d6a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8e75d6a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8e75d6a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5597:
 #0: ffff8880329a20a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211
1 lock held by syz.3.36/6180:
 #0: ffff88807b338fb8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
 #0: ffff88807b338fb8 (&mm->mmap_lock){++++}-{4:4}, at: exit_mm+0x73/0x250 kernel/exit.c:557
1 lock held by syz.3.36/6181:
 #0: ffff88807b338fb8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
 #0: ffff88807b338fb8 (&mm->mmap_lock){++++}-{4:4}, at: exit_mm+0x73/0x250 kernel/exit.c:557
2 locks held by syz.5.555/8621:
 #0: ffff8880b863ade0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:647
 #1: ffff8880b8624588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933
1 lock held by syz.4.558/8634:
1 lock held by syz.2.559/8639:

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 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+0x1002/0x1060 kernel/hung_task.c:561
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 8631 Comm: syz.0.557 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:memset_orig+0x25/0xb0 arch/x86/lib/memset_64.S:64
Code: 90 90 90 90 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 01 01 48 0f af c1 41 89 f9 41 83 e1 07 75 74 48 89 d1 48 c1 e9 06 <74> 39 66 0f 1f 84 00 00 00 00 00 48 ff c9 48 89 07 48 89 47 08 48
RSP: 0018:ffffc9000daf76f8 EFLAGS: 00000247
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000020 RSI: 0000000000000000 RDI: ffffc9000daf7780
RBP: ffffc9000daf7878 R08: ffffc9000daf779f R09: 0000000000000000
R10: ffffc9000daf7780 R11: fffff52001b5eef4 R12: ffff8880336438c0
R13: dffffc0000000000 R14: 1ffff92001b5eeec R15: ffff88807c926600
FS:  00007f7421d1a6c0(0000) GS:ffff888125435000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000002f2030 CR3: 000000007e904000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __unix_dgram_recvmsg+0x707/0xd60 net/unix/af_unix.c:2622
 sock_recvmsg_nosec+0x10c/0x140 net/socket.c:1151
 ____sys_recvmsg+0x245/0x510 net/socket.c:-1
 ___sys_recvmsg+0x215/0x590 net/socket.c:2930
 do_recvmmsg+0x334/0x800 net/socket.c:3025
 __sys_recvmmsg net/socket.c:3099 [inline]
 __do_sys_recvmmsg net/socket.c:3122 [inline]
 __se_sys_recvmmsg net/socket.c:3115 [inline]
 __x64_sys_recvmmsg+0x198/0x250 net/socket.c:3115
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7420d9c799
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:00007f7421d1a028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f7421016090 RCX: 00007f7420d9c799
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003
RBP: 00007f7420e32c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7421016128 R14: 00007f7421016090 R15: 00007fff17ff7168
 </TASK>