rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 0, t=10502 jiffies, g=6729, q=76 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10496 (4294954385-4294943889), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10496 jiffies! g6729 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:27976 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </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 PID: 5815 Comm: syz-executor331 Not tainted 6.6.102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__access_ok arch/x86/include/asm/uaccess_64.h:91 [inline]
RIP: 0010:_copy_from_user+0x41/0xe0 lib/usercopy.c:15
Code: 67 fd 48 c7 c7 c0 10 fc 8a be 0e 00 00 00 e8 c6 87 aa fd e8 e1 12 31 00 84 c0 74 0a e8 d8 2c 67 fd 49 89 df eb 54 4e 8d 24 3b <48> c7 c7 ff ff ff ff 4c 89 e6 e8 00 31 67 fd 4c 89 e7 4c 89 fe e8
RSP: 0018:ffffc90004a5fbd8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000018 RCX: ffff888024f69e00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff8d3e6640
RBP: ffffc90004a5fcf0 R08: ffffffff8e4a882f R09: 1ffffffff1c95105
R10: dffffc0000000000 R11: fffffbfff1c95106 R12: 00007ffd7b7a6428
R13: dffffc0000000000 R14: ffffc90004a5fc60 R15: 00007ffd7b7a6410
FS:  000055557c4213c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6e43c56fa0 CR3: 00000000794c3000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 copy_from_user include/linux/uaccess.h:183 [inline]
 restore_altstack+0x9e/0x4a0 kernel/signal.c:4290
 __ia32_sys_rt_sigreturn+0x1f6/0x7b0 arch/x86/kernel/signal_64.c:263
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6e43c56fa9
Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25
RSP: 002b:00007ffd7b7a6400 EFLAGS: 00000206 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f6e43c56fa9
RDX: 00007ffd7b7a6400 RSI: 00007ffd7b7a6530 RDI: 0000000000000021
RBP: 0000000000000000 R08: 00007f6e43bf6990 R09: 00007f6e43bf6990
R10: 0000000000000000 R11: 0000000000000206 R12: 00007f6e43c9603c
R13: 00007f6e43c8f1d1 R14: 00007ffd7b7a69d0 R15: 0000000000000000
 </TASK>