rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5974/2:b..l rcu: (detected by 0, t=10503 jiffies, g=11817, q=565 ncpus=2) task:syz.1.23 state:R running task stack:25544 pid:5974 ppid:5768 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6700 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7010 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:lock_acquire+0x1f2/0x410 kernel/locking/lockdep.c:5758 Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 66 43 c7 44 3c 09 00 00 43 c6 44 3c 0b 00 RSP: 0018:ffffc9000b79f6a0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 7a89e5f5f7865300 RDX: 0000000000000000 RSI: ffffffff8aaace60 RDI: ffffffff8afc73a0 RBP: ffffc9000b79f7a8 R08: dffffc0000000000 R09: 1ffffffff21b2ca0 R10: dffffc0000000000 R11: fffffbfff21b2ca1 R12: 1ffff920016f3ee0 R13: ffffffff8cd2ffa0 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] percpu_ref_tryget_many include/linux/percpu-refcount.h:241 [inline] percpu_ref_tryget+0x31/0x180 include/linux/percpu-refcount.h:266 css_tryget include/linux/cgroup_refcnt.h:45 [inline] get_mem_cgroup_from_mm+0x102/0x290 mm/memcontrol.c:1094 __mem_cgroup_charge+0x15/0x80 mm/memcontrol.c:7110 mem_cgroup_charge include/linux/memcontrol.h:686 [inline] shmem_add_to_page_cache+0x8e7/0x1b40 mm/shmem.c:784 shmem_get_folio_gfp+0xf05/0x2ac0 mm/shmem.c:2071 shmem_get_folio mm/shmem.c:2164 [inline] shmem_write_begin+0xf2/0x420 mm/shmem.c:2706 generic_perform_write+0x2fb/0x5b0 mm/filemap.c:4031 shmem_file_write_iter+0xfb/0x120 mm/shmem.c:2883 call_write_iter include/linux/fs.h:2018 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x43b/0x940 fs/read_write.c:584 ksys_write+0x147/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fc1e038e1ff RSP: 002b:00007fc1de5f5df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000400000 RCX: 00007fc1e038e1ff RDX: 0000000000400000 RSI: 00007fc1d61d6000 RDI: 0000000000000006 RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000010e9 R10: 00002000000022c2 R11: 0000000000000293 R12: 0000000000000006 R13: 00007fc1de5f5ef0 R14: 00007fc1de5f5eb0 R15: 00007fc1d61d6000 rcu: rcu_preempt kthread starved for 10162 jiffies! g11817 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:26920 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x160/0x280 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148 Code: cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d 23 2b 40 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56 RSP: 0018:ffffffff8ca07d80 EFLAGS: 000002c2 RAX: e921768376c1f400 RBX: ffffffff8161a02b RCX: e921768376c1f400 RDX: 0000000000000001 RSI: ffffffff8aaabce0 RDI: ffffffff8afc73a0 RBP: ffffffff8ca07eb8 R08: ffff8880b8e36b2b R09: 1ffff110171c6d65 R10: dffffc0000000000 R11: ffffed10171c6d66 R12: ffffffff8e4a39e8 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1952688 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd0c69212c0 CR3: 000000002b0ef000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:753 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97 cpuidle_idle_call kernel/sched/idle.c:170 [inline] do_idle+0x1eb/0x510 kernel/sched/idle.c:282 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380 rest_init+0x2e2/0x300 init/main.c:744 arch_call_rest_init+0xe/0x10 init/main.c:841 start_kernel+0x459/0x4e0 init/main.c:1086 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555 x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536 secondary_startup_64_no_verify+0x179/0x17b