rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P15003/1:b..l rcu: (detected by 1, t=10506 jiffies, g=108761, q=438 ncpus=2) task:syz.3.2426 state:R running task stack:26056 pid:15003 tgid:14998 ppid:5605 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7188 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7512 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:476 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x1fe/0x790 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872 Code: 05 fb fd 25 12 83 f8 07 0f 87 d9 02 00 00 48 0f a3 05 06 17 f3 0e 0f 82 a4 02 00 00 8b 35 8e 4a f3 0e 85 f6 0f 85 bf 00 00 00 <48> 8b 44 24 30 65 48 2b 05 9d fd 25 12 0f 85 ed 02 00 00 48 83 c4 RSP: 0018:ffffc90007cb6b90 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff8def9308 RDI: ffffffff8c1c3500 RBP: ffffffff8e7e54e0 R08: 00000000dacd92cc R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495 __unwind_start+0x3d1/0x7f0 arch/x86/kernel/unwind_orc.c:787 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0x73/0xf0 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x162/0x1e0 mm/page_owner.c:165 __set_page_owner+0x8c/0x540 mm/page_owner.c:341 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1858 prep_new_page mm/page_alloc.c:1866 [inline] get_page_from_freelist+0x11a6/0x33b0 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x27c/0x2bc0 mm/page_alloc.c:5226 alloc_pages_mpol+0x1fb/0x540 mm/mempolicy.c:2490 folio_alloc_mpol_noprof+0x36/0x260 mm/mempolicy.c:2509 vma_alloc_folio_noprof+0xed/0x1d0 mm/mempolicy.c:2544 folio_prealloc mm/memory.c:1191 [inline] wp_page_copy mm/memory.c:3859 [inline] do_wp_page+0xd75/0x4350 mm/memory.c:4320 handle_pte_fault mm/memory.c:6427 [inline] __handle_mm_fault+0x1ab6/0x2a00 mm/memory.c:6549 handle_mm_fault+0x36d/0xa20 mm/memory.c:6718 do_user_addr_fault+0x74c/0x12f0 arch/x86/mm/fault.c:1385 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0010:__put_user_nocheck_4+0x3/0x10 arch/x86/lib/putuser.S:104 Code: d9 0f 01 cb 89 01 31 c9 0f 01 ca e9 c7 d7 03 00 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 01 cb <89> 01 31 c9 0f 01 ca c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90007cb79d8 EFLAGS: 00050246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000200000339030 RDX: 0000000000080000 RSI: ffffffff89554fc1 RDI: ffff8880284f2500 RBP: ffffc90007cb7d78 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000000 R13: 0000200000339000 R14: ffffc90007cb7dbc R15: 0000000000000002 ____sys_recvmsg+0x2ec/0x640 net/socket.c:2931 ___sys_recvmsg+0x16a/0x1a0 net/socket.c:2960 do_recvmmsg+0x301/0x760 net/socket.c:3055 __sys_recvmmsg net/socket.c:3129 [inline] __do_sys_recvmmsg net/socket.c:3152 [inline] __se_sys_recvmmsg net/socket.c:3145 [inline] __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3145 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5619f9cdd9 RSP: 002b:00007f561aec6028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f561a216090 RCX: 00007f5619f9cdd9 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007f561a032d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f561a216128 R14: 00007f561a216090 R15: 00007ffeffd9fb18 rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g108761 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=67232 rcu: rcu_preempt kthread starved for 10506 jiffies! g108761 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27992 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7282 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 15021 Comm: syz.1.2435 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:kasan_mem_to_shadow include/linux/kasan.h:66 [inline] RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:141 [inline] RIP: 0010:memory_is_poisoned mm/kasan/generic.c:172 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:191 [inline] RIP: 0010:kasan_check_range+0x4c/0x1e0 mm/kasan/generic.c:200 Code: cc cc cc 48 b8 00 00 00 00 00 00 00 ff eb 0a 48 b8 00 00 00 00 00 80 ff ff 48 39 c7 0f 82 c2 00 00 00 4c 8d 54 37 ff 48 89 fd <48> b8 00 00 00 00 00 fc ff df 4d 89 d1 48 c1 ed 03 49 c1 e9 03 48 RSP: 0000:ffffc90000007d08 EFLAGS: 00000006 RAX: ffff800000000000 RBX: ffffffff9b35c888 RCX: ffffffff81e4c7a3 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff9b35c888 RBP: ffffffff9b35c888 R08: 0000000000000000 R09: fffff52000000f9a R10: ffffffff9b35c88b R11: 0000000000000001 R12: 0000000000000002 R13: ffff88802b17d300 R14: dffffc0000000000 R15: 1ffff92000000fb0 FS: 000055556b775500(0000) GS:ffff888124379000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33123ffc CR3: 0000000078b8c000 CR4: 00000000003526f0 Call Trace: instrument_atomic_read include/linux/instrumented.h:82 [inline] atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline] queued_spin_is_locked include/asm-generic/qspinlock.h:57 [inline] debug_spin_unlock kernel/locking/spinlock_debug.c:101 [inline] do_raw_spin_unlock+0x53/0x1e0 kernel/locking/spinlock_debug.c:141 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:177 [inline] _raw_spin_unlock_irqrestore+0x22/0x80 kernel/locking/spinlock.c:198 debug_object_activate+0x331/0x490 lib/debugobjects.c:853 debug_hrtimer_activate kernel/time/hrtimer.c:485 [inline] debug_activate kernel/time/hrtimer.c:528 [inline] enqueue_hrtimer+0x75/0x2f0 kernel/time/hrtimer.c:1109 __run_hrtimer kernel/time/hrtimer.c:1946 [inline] __hrtimer_run_queues+0x73d/0xa00 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__rcu_read_unlock+0x64/0x5e0 kernel/rcu/tree_plugin.h:437 Code: 03 38 d0 7c 08 84 d2 0f 85 0a 02 00 00 83 ab c4 04 00 00 01 75 3b 48 8d bb c8 04 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa <48> c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 RSP: 0000:ffffc9000870f4f8 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffff888038f82500 RCX: ffffc9000870f4f4 RDX: ffff888038f829c8 RSI: ffffffff8def9308 RDI: ffff888038f829c8 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000015b46 R12: ffffc9000870f5f0 R13: ffffc9000870f5a0 R14: ffffc9000870fc78 R15: ffffc9000870f5d4 rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0x3c8/0x2090 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4569 [inline] slab_alloc_node mm/slub.c:4898 [inline] kmem_cache_alloc_noprof+0x241/0x6e0 mm/slub.c:4905 new_handle fs/jbd2/transaction.c:457 [inline] jbd2__journal_start+0x194/0x6a0 fs/jbd2/transaction.c:485 __ext4_journal_start_sb+0x36d/0x670 fs/ext4/ext4_jbd2.c:114 __ext4_journal_start fs/ext4/ext4_jbd2.h:242 [inline] ext4_dirty_inode+0xa1/0x130 fs/ext4/inode.c:6584 __mark_inode_dirty+0x1f3/0x1720 fs/fs-writeback.c:2623 generic_update_time fs/inode.c:2192 [inline] file_update_time_flags+0x46b/0x500 fs/inode.c:2422 ext4_page_mkwrite+0x324/0x1890 fs/ext4/inode.c:6753 do_page_mkwrite+0x17a/0x440 mm/memory.c:3668 do_shared_fault mm/memory.c:5969 [inline] do_fault+0x3b5/0x1750 mm/memory.c:6031 do_pte_missing mm/memory.c:4550 [inline] handle_pte_fault mm/memory.c:6411 [inline] __handle_mm_fault+0x187d/0x2a00 mm/memory.c:6549 handle_mm_fault+0x36d/0xa20 mm/memory.c:6718 do_user_addr_fault+0x5a3/0x12f0 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f74a7c71560 Code: 89 dc 41 83 e4 03 0f 85 ca 01 00 00 4c 89 ff be 04 00 00 00 e8 81 93 fe ff 49 8b 47 40 41 83 47 30 04 48 8d 50 fc 49 89 57 40 <89> 68 fc 41 8b 47 30 48 83 c4 28 5b 5d 41 5c 41 5d 41 5e 41 5f c3 RSP: 002b:00007fffc5e14570 EFLAGS: 00010202 RAX: 0000001b33124000 RBX: 0000000000000000 RCX: 00000000003ffde8 RDX: 0000001b33123ffc RSI: 00000000003ffde8 RDI: 00007f74a8b45700 RBP: 0000000000000000 R08: 0000000000000000 R09: 00007f74a8002000 R10: 00007f74a8b45700 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000003b60 R14: ffffffff81ad98d8 R15: 00007f74a8b45720