rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5881/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=9121, q=648 ncpus=2)
task:syz.3.5         state:R  running task     stack:25352 pid:5881  ppid:5788   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866
 preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 finish_fault+0x490/0x970 mm/memory.c:4486
 do_read_fault mm/memory.c:4620 [inline]
 do_fault mm/memory.c:4753 [inline]
 do_pte_missing mm/memory.c:3688 [inline]
 handle_pte_fault mm/memory.c:5025 [inline]
 __handle_mm_fault mm/memory.c:5166 [inline]
 handle_mm_fault+0x38ae/0x4920 mm/memory.c:5331
 faultin_page mm/gup.c:868 [inline]
 __get_user_pages+0x5ea/0x1470 mm/gup.c:1167
 populate_vma_page_range+0x2b6/0x370 mm/gup.c:1593
 __mm_populate+0x24c/0x380 mm/gup.c:1696
 mm_populate include/linux/mm.h:3328 [inline]
 vm_mmap_pgoff+0x2e7/0x400 mm/util.c:561
 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: 0033:0x7f71b2b8eba9
RSP: 002b:00007f71b0dd5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f71b2dd6180 RCX: 00007f71b2b8eba9
RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007f71b2c11e19 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f71b2dd6218 R14: 00007f71b2dd6180 R15: 00007ffce8256f88
 </TASK>
rcu: rcu_preempt kthread starved for 10511 jiffies! g9121 f0x0 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:27480 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5883 Comm: syz.1.2 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:copy_user_generic arch/x86/include/asm/uaccess_64.h:112 [inline]
RIP: 0010:raw_copy_from_user arch/x86/include/asm/uaccess_64.h:127 [inline]
RIP: 0010:_copy_from_user+0x86/0xe0 lib/usercopy.c:23
Code: 89 d8 4c 01 f8 78 67 4c 39 f8 72 62 e8 63 c1 66 fd 0f ae e8 4c 89 f7 89 de e8 56 0e be fd 0f 01 cb 48 89 d9 4c 89 fe 4c 89 f7 <e8> f5 a6 42 06 49 89 cf 0f 01 ca 31 ff 4c 89 fe e8 75 c5 66 fd 4d
RSP: 0018:ffffc90004f47cd8 EFLAGS: 00040246
RAX: ffffffff841ece01 RBX: 00000000000000c0 RCX: 00000000000000c0
RDX: 0000000000000001 RSI: 00007f9c45d97b68 RDI: ffffc90004f47d60
RBP: ffffc90004f47f10 R08: ffffc90004f47e1f R09: 1ffff920009e8fc3
R10: dffffc0000000000 R11: fffff520009e8fc4 R12: 00007f9c45d97c28
R13: 1ffff920009e8ffe R14: ffffc90004f47d60 R15: 00007f9c45d97b68
FS:  00007f9c45d986c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc8ef5e9000 CR3: 000000002ee87000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 copy_from_user include/linux/uaccess.h:183 [inline]
 restore_sigcontext arch/x86/kernel/signal_64.c:59 [inline]
 __ia32_sys_rt_sigreturn+0x27a/0x7b0 arch/x86/kernel/signal_64.c:266
 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: 0033:0x7f9c44f2ada9
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:00007f9c45d97b40 EFLAGS: 00000246 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007f9c451d6098 RCX: 00007f9c44f2ada9
RDX: 00007f9c45d97b40 RSI: 00007f9c45d97c70 RDI: 0000000000000011
RBP: 00007f9c451d6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9c451d6128 R14: 00007fff4d678af0 R15: 00007fff4d678bd8
 </TASK>
sched: RT throttling activated