rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5835/1:b..l P7195 rcu: (detected by 1, t=10503 jiffies, g=15137, q=469 ncpus=2) task:syz.4.405 state:R running task stack:24808 pid:7195 tgid:7195 ppid:5840 task_flags:0x400040 flags:0x0000400a Call Trace: task:syz-executor state:R running task stack:20352 pid:5835 tgid:5835 ppid:5830 task_flags:0x400140 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6947 preempt_schedule+0xe4/0xf0 kernel/sched/core.c:6971 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range+0x5e5f/0x6680 mm/memory.c:1194 copy_pmd_range mm/memory.c:1255 [inline] copy_pud_range mm/memory.c:1292 [inline] copy_p4d_range mm/memory.c:1316 [inline] copy_page_range+0xe57/0x13a0 mm/memory.c:1410 dup_mmap kernel/fork.c:726 [inline] dup_mm kernel/fork.c:1734 [inline] copy_mm+0x130d/0x22c0 kernel/fork.c:1786 copy_process+0x17de/0x3d10 kernel/fork.c:2429 kernel_clone+0x242/0x930 kernel/fork.c:2844 __do_sys_clone kernel/fork.c:2987 [inline] __se_sys_clone kernel/fork.c:2971 [inline] __x64_sys_clone+0x268/0x2e0 kernel/fork.c:2971 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1745f839d3 RSP: 002b:00007fffc0c47958 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1745f839d3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 00005555823c97d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 0000000000026491 R15: 00007fffc0c47af0 rcu: rcu_preempt kthread starved for 10549 jiffies! g15137 f0x0 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:26688 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x163/0x360 kernel/sched/core.c:6860 schedule_timeout+0x15b/0x2b0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2e1/0x1340 kernel/rcu/tree.c:2046 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2248 kthread+0x7b7/0x940 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 7205 Comm: syz.1.409 Not tainted 6.14.0-syzkaller-g0c2623cef4f4 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:trylock_clear_pending kernel/locking/qspinlock_paravirt.h:122 [inline] RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:431 [inline] RIP: 0010:__pv_queued_spin_lock_slowpath+0x7de/0xdc0 kernel/locking/qspinlock.c:325 Code: c0 75 58 0f b7 84 24 b0 00 00 00 66 b9 01 00 66 f0 41 0f b1 0e 0f 84 db 01 00 00 eb b2 48 8d 8c 24 b0 00 00 00 80 e1 07 fe c1 <38> c1 7c 83 48 8d bc 24 b0 00 00 00 e8 11 15 fb f5 e9 71 ff ff ff RSP: 0018:ffffc90003f5f940 EFLAGS: 00000202 RAX: 0000000000000002 RBX: 1ffff920007ebf3e RCX: ffffc90003f5f901 RDX: ffffc9000b199000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc90003f5fa78 R08: ffffffff905fb977 R09: 1ffffffff20bf72e R10: dffffc0000000000 R11: fffffbfff20bf72f R12: 00000000ffffd280 R13: dffffc0000000000 R14: ffff88802388b2d0 R15: ffffc90003f5fa00 FS: 00007fab743786c0(0000) GS:ffff88812509c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000004 CR3: 000000001dee8000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:572 [inline] queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x276/0x370 kernel/locking/spinlock_debug.c:116 spin_lock include/linux/spinlock.h:351 [inline] d_instantiate+0x64/0xa0 fs/dcache.c:1937 alloc_path_pseudo fs/file_table.c:364 [inline] alloc_file_pseudo+0x1cf/0x320 fs/file_table.c:376 __anon_inode_getfile fs/anon_inodes.c:109 [inline] anon_inode_getfile+0xc8/0x180 fs/anon_inodes.c:147 __do_sys_perf_event_open kernel/events/core.c:13370 [inline] __se_sys_perf_event_open+0x2250/0x34b0 kernel/events/core.c:13081 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fab7358d169 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:00007fab74378038 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007fab737a5fa0 RCX: 00007fab7358d169 RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000480 RBP: 00007fab7360e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fab737a5fa0 R15: 00007ffe3eb1b528