rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6097/1:b..l P10260/1:b..l P10328/1:b..l rcu: (detected by 1, t=10502 jiffies, g=33541, q=199 ncpus=2) task:syz.8.1062 state:R running task stack:24536 pid:10328 tgid:10323 ppid:6363 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0x14ea/0x5050 kernel/sched/core.c:6867 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7194 irqentry_exit+0x597/0x620 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:rcu_read_unlock include/linux/rcupdate.h:895 [inline] RIP: 0010:percpu_ref_put_many include/linux/percpu-refcount.h:337 [inline] RIP: 0010:percpu_ref_put+0xb7/0x180 include/linux/percpu-refcount.h:351 Code: 42 80 3c 28 00 74 08 4c 89 f7 e8 f4 83 f6 ff 49 8b 06 a8 03 75 65 65 48 ff 08 e8 44 c2 60 09 85 c0 74 3a e8 4b 68 73 ff 84 c0 <75> 31 e8 32 c2 60 09 85 c0 74 28 80 3d bb d0 a2 0d 00 75 1f c6 05 RSP: 0018:ffffc90018ca7810 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffffff823641b9 RCX: 0000000080000001 RDX: 00000000024f949b RSI: ffffffff8c0739e0 RDI: ffffffff8c0739a0 RBP: 0000000000000cc0 R08: ffffffff823641b9 R09: ffffffff8e55a360 R10: dffffc0000000000 R11: fffffbfff1fde36f R12: dffffc0000000000 R13: dffffc0000000000 R14: ffff888051af4250 R15: ffffea0000f400b8 css_put include/linux/cgroup_refcnt.h:79 [inline] __mem_cgroup_charge+0x149/0x1e0 mm/memcontrol.c:4746 mem_cgroup_charge include/linux/memcontrol.h:663 [inline] shmem_alloc_and_add_folio+0x7d0/0xf80 mm/shmem.c:1965 shmem_get_folio_gfp+0x5a9/0x1670 mm/shmem.c:2579 shmem_get_folio mm/shmem.c:2685 [inline] shmem_write_begin+0x16c/0x330 mm/shmem.c:3338 generic_perform_write+0x2e2/0x8f0 mm/filemap.c:4314 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3513 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x61d/0xb90 fs/read_write.c:686 ksys_write+0x150/0x270 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f98e4d5b78e RSP: 002b:00007f98e5ba1da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f98e5ba26c0 RCX: 00007f98e4d5b78e RDX: 0000000001000000 RSI: 00007f98daa00000 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 00007f98e5ba1ee0 R14: 00007f98e5ba1ea0 R15: 00007f98daa00000 task:syz.4.1044 state:R running task stack:25536 pid:10260 tgid:10256 ppid:5820 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0x14ea/0x5050 kernel/sched/core.c:6867 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7051 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+0x3f/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] wp_page_copy mm/memory.c:3823 [inline] do_wp_page+0x4207/0x5990 mm/memory.c:4183 handle_pte_fault mm/memory.c:6292 [inline] __handle_mm_fault mm/memory.c:6414 [inline] handle_mm_fault+0x1520/0x32a0 mm/memory.c:6583 do_user_addr_fault+0x75b/0x1360 arch/x86/mm/fault.c:1385 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 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 62 d0 79 f5 90 90 90 90 90 90 90 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 e9 3c d0 79 f5 90 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90019c878b8 EFLAGS: 00050202 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000020000028c030 RDX: ffff88802f1a5b80 RSI: 0000000000000002 RDI: 00000000ffffffff RBP: ffffc90019c87a30 R08: ffffc90019c87687 R09: 1ffff92003390ed0 R10: dffffc0000000000 R11: fffff52003390ed1 R12: 1ffff92003390f24 R13: 0000000000000002 R14: 000020000028c000 R15: dffffc0000000000 ____sys_recvmsg+0x2be/0x4a0 net/socket.c:2825 ___sys_recvmsg+0x215/0x590 net/socket.c:2854 do_recvmmsg+0x334/0x800 net/socket.c:2949 __sys_recvmmsg net/socket.c:3023 [inline] __do_sys_recvmmsg net/socket.c:3046 [inline] __se_sys_recvmmsg net/socket.c:3039 [inline] __x64_sys_recvmmsg+0x198/0x250 net/socket.c:3039 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7feaeb99aeb9 RSP: 002b:00007feaec816028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007feaebc16090 RCX: 00007feaeb99aeb9 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007feaeba08c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007feaebc16128 R14: 00007feaebc16090 R15: 00007fff5fe1b178 task:udevd state:R running task stack:23288 pid:6097 tgid:6097 ppid:5189 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0x14ea/0x5050 kernel/sched/core.c:6867 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7194 irqentry_exit+0x597/0x620 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x221/0x330 kernel/locking/lockdep.c:5872 Code: ff ff ff e8 41 b0 f6 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 2b 61 52 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 fb f1 6f ff cc 48 8d 3d 38 15 52 RSP: 0018:ffffc9000b417570 EFLAGS: 00000282 RAX: 9493b9a224483200 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 000000005594689c RSI: ffffffff8df343a3 RDI: ffffffff8c073a00 RBP: ffffffff81d3cc06 R08: ffffffff81d3cc06 R09: ffffffff8e55a360 R10: dffffc0000000000 R11: ffffffff81afb170 R12: 0000000000000002 R13: ffffffff8e55a360 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] is_bpf_text_address+0x47/0x2b0 kernel/bpf/core.c:744 kernel_text_address+0xa5/0xe0 kernel/extable.c:125 __kernel_text_address+0xd/0x30 kernel/extable.c:79 unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:385 arch_stack_walk+0xfb/0x150 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 slab_free_hook mm/slub.c:2501 [inline] slab_free mm/slub.c:6674 [inline] kmem_cache_free+0x46e/0x610 mm/slub.c:6785 remove_vma mm/vma.c:467 [inline] vms_complete_munmap_vmas+0x625/0x890 mm/vma.c:1336 do_vmi_align_munmap+0x3b7/0x4b0 mm/vma.c:1579 do_vmi_munmap+0x252/0x2d0 mm/vma.c:1627 __vm_munmap+0x22c/0x3d0 mm/vma.c:3247 __do_sys_munmap mm/mmap.c:1077 [inline] __se_sys_munmap mm/mmap.c:1074 [inline] __x64_sys_munmap+0x60/0x70 mm/mmap.c:1074 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f75ceb1e097 RSP: 002b:00007ffdafa18358 EFLAGS: 00000246 ORIG_RAX: 000000000000000b RAX: ffffffffffffffda RBX: 0000563d0d6209b0 RCX: 00007f75ceb1e097 RDX: 0000563d0d635058 RSI: 0000000000000600 RDI: 00007f75cf15d000 RBP: 0000000000000019 R08: 0000563d0d620c60 R09: 0000000000000003 R10: 0000000000000040 R11: 0000000000000246 R12: 0000563d0d62f970 R13: 00007f75cf2c039c R14: 0000000000043400 R15: 0000000000000009 rcu: rcu_preempt kthread starved for 10520 jiffies! g33541 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:27744 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0x14ea/0x5050 kernel/sched/core.c:6867 __schedule_loop kernel/sched/core.c:6949 [inline] schedule+0x164/0x360 kernel/sched/core.c:6964 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x1560 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:2285 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 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: 10330 Comm: syz.6.1061 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210 Code: 89 fb e8 23 00 00 00 48 8b 3d c4 2e 33 0c 48 89 de 5b e9 83 c4 5c 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 0d a8 38 2e 11 65 8b 15 c9 38 2e RSP: 0018:ffffc90018e1fcf8 EFLAGS: 00000212 RAX: f3f3f304f1f1f1f1 RBX: 0000000000000000 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f740e415fa8 RBP: ffffc90018e1fdc8 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: fffff520031c3fce R12: 0000000000000000 R13: 0000000000000080 R14: 1ffff920031c3fa8 R15: 1ffff920031c3fc4 FS: 00007f740f0a46c0(0000) GS:ffff8881256f5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000001f030 CR3: 0000000078879000 CR4: 0000000000350ef0 Call Trace: do_futex+0x8b/0x420 kernel/futex/syscalls.c:114 __do_sys_futex kernel/futex/syscalls.c:207 [inline] __se_sys_futex+0x3a8/0x450 kernel/futex/syscalls.c:188 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f740e19aeb9 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:00007f740f0a40e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f740e415fa8 RCX: 00007f740e19aeb9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f740e415fa8 RBP: 00007f740e415fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f740e416038 R14: 00007ffee8be4300 R15: 00007ffee8be43e8