rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6216/1:b..l rcu: (detected by 1, t=10502 jiffies, g=23889, q=12 ncpus=2) task:syz.2.69 state:R running task stack:24808 pid:6216 tgid:6211 ppid:5640 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0xa00 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:rcu_preempt_read_exit kernel/rcu/tree_plugin.h:396 [inline] RIP: 0010:__rcu_read_unlock+0x3f/0x5e0 kernel/rcu/tree_plugin.h:435 Code: 12 48 8d bb c4 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> d2 0f 85 0a 02 00 00 83 ab c4 04 00 00 01 75 3b 48 8d bb c8 04 RSP: 0018:ffffc90002e8f318 EFLAGS: 00000202 RAX: 0000000000000007 RBX: ffff888026d81f00 RCX: ffffc90002e8f314 RDX: 0000000000000000 RSI: ffffffff8df333b0 RDI: ffff888026d823c4 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000007 R10: 0000000000000200 R11: 000000000001460c R12: ffffc90002e8f410 R13: ffffc90002e8f3c0 R14: ffffc90002e8f8a8 R15: ffffc90002e8f3f4 rcu_read_unlock include/linux/rcupdate.h:873 [inline] class_rcu_destructor include/linux/rcupdate.h:1183 [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 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2705 [inline] slab_free mm/slub.c:6405 [inline] kmem_cache_free+0x127/0x6b0 mm/slub.c:6532 free_buffer_head+0x4e/0x100 fs/buffer.c:2978 try_to_free_buffers+0x252/0x420 fs/buffer.c:2919 filemap_release_folio+0x28e/0x340 mm/filemap.c:4539 mapping_evict_folio+0x28d/0x370 mm/truncate.c:336 mapping_try_invalidate+0x1e3/0x3c0 mm/truncate.c:560 invalidate_bdev+0x8d/0xb0 block/bdev.c:102 blkdev_flushbuf block/ioctl.c:526 [inline] blkdev_common_ioctl+0xf83/0x2b80 block/ioctl.c:658 blkdev_ioctl+0x43b/0x6f0 block/ioctl.c:791 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fee3699de59 RSP: 002b:00007fee37793028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fee36c26090 RCX: 00007fee3699de59 RDX: 0000000000000000 RSI: 0000000000001261 RDI: 0000000000000003 RBP: 00007fee36a33e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fee36c26128 R14: 00007fee36c26090 R15: 00007ffc10fa6378 rcu: rcu_preempt kthread timer wakeup didn't happen for 10547 jiffies! g23889 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=6309 rcu: rcu_preempt kthread starved for 10553 jiffies! g23889 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27432 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325 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: CPU: 1 UID: 0 PID: 6237 Comm: syz.1.71 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64 Code: d6 86 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 c3 57 11 00 fb f4 bc 48 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc900057d77b8 EFLAGS: 00000242 RAX: 0000000000010738 RBX: 0000000000000003 RCX: 0000000000000004 RDX: 0000000000000000 RSI: ffffffff8df5902e RDI: ffffffff8c1e8f80 RBP: ffff88807f8ac310 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: 0000000000000003 R14: ffff8880b853c600 R15: 0000000000000000 FS: 00007fe1e36606c0(0000) GS:ffff8881243e7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000002000 CR3: 0000000079c9e000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline] kvm_wait arch/x86/kernel/kvm.c:1096 [inline] kvm_wait+0x124/0x160 arch/x86/kernel/kvm.c:1078 pv_wait arch/x86/include/asm/paravirt-spinlock.h:83 [inline] pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:466 [inline] __pv_queued_spin_lock_slowpath+0x4b0/0xc00 kernel/locking/qspinlock.c:325 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt-spinlock.h:35 [inline] queued_spin_lock_slowpath arch/x86/include/asm/paravirt-spinlock.h:66 [inline] queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x1e0/0x260 kernel/locking/spinlock_debug.c:116 spin_lock_bh include/linux/spinlock.h:348 [inline] lock_sock_nested+0x5f/0xf0 net/core/sock.c:3844 lock_sock include/net/sock.h:1713 [inline] tipc_sendstream+0x41/0x70 net/tipc/socket.c:1549 sock_sendmsg_nosec net/socket.c:775 [inline] __sock_sendmsg net/socket.c:790 [inline] ____sys_sendmsg+0xa4d/0xbe0 net/socket.c:2684 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2738 __sys_sendmmsg+0x20c/0x440 net/socket.c:2827 __do_sys_sendmmsg net/socket.c:2854 [inline] __se_sys_sendmmsg net/socket.c:2851 [inline] __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2851 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe1e279de59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe1e3660028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007fe1e2a26090 RCX: 00007fe1e279de59 RDX: 00000000000009a6 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 00007fe1e2833e6f R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000000a R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe1e2a26128 R14: 00007fe1e2a26090 R15: 00007ffc58bc9f48