rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P7940/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=19917, q=702 ncpus=2)
task:syz.2.530       state:R  running task     stack:27608 pid:7940  tgid:7938  ppid:5831   task_flags:0x40044c flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7090
 irqentry_exit+0x36/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:stack_access_ok+0x166/0x200 arch/x86/kernel/unwind_orc.c:398
Code: 0f 85 95 00 00 00 48 8b 43 10 49 39 ee 77 29 48 39 e8 76 24 4c 01 e5 48 39 e8 0f 93 c0 49 39 ee 0f 92 c2 21 d0 48 83 c4 08 5b <5d> 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc 48 83 c4 08 31 c0 5b 5d
RSP: 0018:ffffc90002ef7508 EFLAGS: 00000296
RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffc90002ef8000
RDX: ffffc90002ef7b01 RSI: ffffc90002ef7b98 RDI: ffffc90002ef75a8
RBP: ffffc90002ef7b98 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 00000000000079fe R12: 0000000000000008
R13: ffffc90002ef75b8 R14: ffffc90002ef75b0 R15: ffffc90002ef0000
 deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline]
 unwind_next_frame+0x15c5/0x20a0 arch/x86/kernel/unwind_orc.c:648
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xb8/0xd0 mm/kasan/generic.c:548
 __call_rcu_common.constprop.0+0x9a/0x9f0 kernel/rcu/tree.c:3082
 slab_free_hook mm/slub.c:2353 [inline]
 slab_free mm/slub.c:4646 [inline]
 kmem_cache_free+0x173/0x4d0 mm/slub.c:4748
 exit_mmap+0x511/0xb90 mm/mmap.c:1309
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 get_signal+0x2673/0x26d0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f037278d169
RSP: 002b:00007f0373504038 EFLAGS: 00000246 ORIG_RAX: 000000000000009d
RAX: 0000000000000000 RBX: 00007f03729a6080 RCX: 00007f037278d169
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 000000000000003e
RBP: 00007f037280e730 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f03729a6080 R15: 00007ffe2fbd92f8
 </TASK>
rcu: rcu_preempt kthread starved for 9647 jiffies! g19917 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:28728 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6860
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2046
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2248
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.15.0-rc1-syzkaller-00065-g3b07108ada81 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:81
Code: 95 5d 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d d3 bc 17 00 fb f4 <c3> cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e007e10 EFLAGS: 000002c6
RAX: 0000000001838949 RBX: 0000000000000000 RCX: ffffffff8b723439
RDX: 0000000000000000 RSI: ffffffff8dbeef8e RDI: ffffffff8bf465c0
RBP: fffffbfff1c12ee8 R08: 0000000000000001 R09: ffffed10170865bd
R10: ffff8880b8432deb R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff8e097740 R14: ffffffff90865310 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881249b3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000002d8030 CR3: 000000002d866000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:748
 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x391/0x510 kernel/sched/idle.c:325
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:423
 rest_init+0x16b/0x2b0 init/main.c:743
 start_kernel+0x3e9/0x4d0 init/main.c:1099
 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:513
 x86_64_start_kernel+0xb0/0xc0 arch/x86/kernel/head64.c:494
 common_startup_64+0x13e/0x148
 </TASK>