rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 0, t=10002 jiffies, g=5013, q=605 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10001 (4294957759-4294947758), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10002 jiffies! g5013 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 4962 Comm: syz.3.1678 Not tainted syzkaller #0 815521559dbd70f1614977c300fd16d58acb59ef
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:next_peer fs/pnode.c:19 [inline]
RIP: 0010:do_make_slave fs/pnode.c:100 [inline]
RIP: 0010:change_mnt_propagation+0x112/0xb00 fs/pnode.c:128
Code: 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 47 51 e7 ff 4d 39 2e 0f 84 8f 00 00 00 <49> 81 c4 d8 00 00 00 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 00 fc
RSP: 0018:ffffc90009fe79c0 EFLAGS: 00000202
RAX: 1ffff110243d3a6c RBX: ffffffffffffff28 RCX: dffffc0000000000
RDX: ffffc90001e12000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc90009fe7a10 R08: ffff88811d67d7ef R09: 0000000000000000
R10: ffff88811d67d7e0 R11: ffffed1023acfafe R12: ffff888121e9d340
R13: ffff888112fc9bb0 R14: ffff888121e9d360 R15: ffff8881406eb500
FS:  00007f1b7ade36c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1b7d117d60 CR3: 0000000132e5e000 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: 0033:0x7f1b7c38efc9
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:00007f1b7ade3038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f1b7c5e5fa0 RCX: 00007f1b7c38efc9
RDX: 0000000000000000 RSI: 0000200000000200 RDI: 0000200000000380
RBP: 00007f1b7c411f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000002125099 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1b7c5e6038 R14: 00007f1b7c5e5fa0 R15: 00007ffd39395dd8
 </TASK>