rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 1, t=10002 jiffies, g=1893, q=855 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10003 (4294953035-4294943032), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10004 jiffies! g1893 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:0     pid:18    tgid:18    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x1322/0x1df0 kernel/sched/core.c:7791
 __schedule_loop kernel/sched/core.c:7872 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7887
 schedule_timeout+0x139/0x3a0 kernel/time/timer.c:2619
 rcu_gp_fqs_loop+0x2f2/0x12f0 kernel/rcu/tree.c:2053
 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:2255
 kthread+0x2ca/0x370 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 591 Comm: syz.2.32 Not tainted syzkaller #0 fd3c8435afaec28a7972119bdf0736bdcfd16977
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:do_make_slave fs/pnode.c:101 [inline]
RIP: 0010:change_mnt_propagation+0xff/0xb00 fs/pnode.c:128
Code: 4e e7 ff 4d 8b 2e 48 c7 c3 28 ff ff ff 4d 89 fc 4d 8d 74 24 20 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 <74> 08 4c 89 f7 e8 e7 4d e7 ff 4d 39 2e 0f 84 8f 00 00 00 49 81 c4
RSP: 0018:ffffc9000139f9c0 EFLAGS: 00000246
RAX: 1ffff1102633a03c RBX: ffffffffffffff28 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000040000 RDI: 0000000000100000
RBP: ffffc9000139fa10 R08: ffff88813425deef R09: 0000000000000000
R10: ffff88813425dee0 R11: ffffed102684bbde R12: ffff8881319d01c0
R13: ffff88812b34daa0 R14: ffff8881319d01e0 R15: ffff88813405e700
FS:  00007f4c2f57e6c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f814d731f98 CR3: 0000000136a6c000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 umount_tree+0xdfd/0xf70 fs/namespace.c:1803
 attach_recursive_mnt+0x6df/0x21e0 fs/namespace.c:2549
 graft_tree+0x157/0x1c0 fs/namespace.c:2684
 do_loopback+0x364/0x4b0 fs/namespace.c:2816
 path_mount+0x582/0x1050 fs/namespace.c:3858
 do_mount fs/namespace.c:3877 [inline]
 __do_sys_mount fs/namespace.c:4087 [inline]
 __se_sys_mount+0x2bd/0x480 fs/namespace.c:4064
 __x64_sys_mount+0xc3/0xf0 fs/namespace.c:4064
 x64_sys_call+0x2021/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f4c2e78e9a9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4c2f57e038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f4c2e9b6320 RCX: 00007f4c2e78e9a9
RDX: 0000000000000000 RSI: 0000200000000080 RDI: 0000200000000240
RBP: 00007f4c2e810d69 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000080700a R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f4c2e9b6320 R15: 00007fff8794bac8
 </TASK>