rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P12229/1:b..l rcu: (detected by 1, t=10503 jiffies, g=46173, q=74 ncpus=2) task:syz.4.1624 state:R running task stack:22528 pid:12229 tgid:12229 ppid:5841 task_flags:0x400640 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b33/0x51f0 kernel/sched/core.c:6767 preempt_schedule_irq+0xfe/0x1c0 kernel/sched/core.c:7090 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 RIP: 0010:lock_acquire+0x167/0x2f0 arch/x86/include/asm/irqflags.h:-1 Code: c7 44 24 10 00 00 00 00 9c 8f 44 24 10 f7 44 24 10 00 02 00 00 0f 85 fd 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 65 48 8b 45 00 <48> 3b 44 24 38 0f 85 72 01 00 00 48 83 c4 40 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc900038ce1a8 EFLAGS: 00000206 RAX: bd5a98662bc4ea00 RBX: ffffffff8ed3dfe0 RCX: bd5a98662bc4ea00 RDX: 0000000000000000 RSI: ffffffff8e4ea087 RDI: ffffffff8ca0e1e0 RBP: ffffffff93657020 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000002 R14: 0000000000000246 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xd5/0x23b0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11e/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x11a/0x1d0 kernel/stacktrace.c:122 save_stack+0xfc/0x1f0 mm/page_owner.c:156 __set_page_owner+0x93/0x530 mm/page_owner.c:329 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1717 prep_new_page mm/page_alloc.c:1725 [inline] get_page_from_freelist+0x351d/0x36b0 mm/page_alloc.c:3652 __alloc_frozen_pages_noprof+0x211/0x5b0 mm/page_alloc.c:4934 alloc_pages_mpol+0x339/0x690 mm/mempolicy.c:2301 folio_alloc_mpol_noprof+0x36/0x70 mm/mempolicy.c:2320 shmem_alloc_folio mm/shmem.c:1854 [inline] shmem_alloc_and_add_folio+0x490/0x1070 mm/shmem.c:1893 shmem_get_folio_gfp+0x655/0x1800 mm/shmem.c:2533 shmem_get_folio mm/shmem.c:2639 [inline] shmem_write_begin+0x17e/0x3a0 mm/shmem.c:3289 generic_perform_write+0x329/0xa10 mm/filemap.c:4102 shmem_file_write_iter+0xf9/0x120 mm/shmem.c:3464 __kernel_write_iter+0x439/0x990 fs/read_write.c:617 dump_emit_page fs/coredump.c:885 [inline] dump_user_range+0x940/0xef0 fs/coredump.c:959 elf_core_dump+0x4098/0x4af0 fs/binfmt_elf.c:2128 do_coredump+0x22c3/0x3260 fs/coredump.c:759 get_signal+0x13ed/0x1730 kernel/signal.c:3019 arch_do_signal_or_restart+0x98/0x840 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] irqentry_exit_to_user_mode+0x7e/0x250 kernel/entry/common.c:231 exc_page_fault+0x5f8/0x920 arch/x86/mm/fault.c:1541 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:0x7fdf9d58d171 RSP: 002b:000000000000a420 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007fdf9d7a5fa0 RCX: 00007fdf9d58d169 RDX: 0000000000000000 RSI: 000000000000a420 RDI: 0000000000022080 RBP: 00007fdf9d60e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fdf9d7a5fa0 R15: 00007ffead8ddf48 rcu: rcu_preempt kthread timer wakeup didn't happen for 10500 jiffies! g46173 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=62300 rcu: rcu_preempt kthread starved for 10501 jiffies! g46173 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:26952 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b33/0x51f0 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5833 Comm: syz-executor Not tainted 6.15.0-rc1-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:trace_hrtimer_expire_entry include/trace/events/timer.h:259 [inline] RIP: 0010:__run_hrtimer kernel/time/hrtimer.c:1758 [inline] RIP: 0010:__hrtimer_run_queues+0x48c/0xd40 kernel/time/hrtimer.c:1825 Code: 7c 24 40 74 08 48 89 df e8 a1 53 7a 00 4c 8b 2b 4c 89 ff 48 8b b4 24 b0 00 00 00 e8 ee c7 7a 0a 0f 1f 44 00 00 e8 14 bb 12 00 <65> 8b 1d e1 e6 b4 11 bf 07 00 00 00 89 de e8 41 bf 12 00 83 fb 07 RSP: 0018:ffffc90000007d40 EFLAGS: 00000006 RAX: ffffffff81b0894c RBX: ffff888022353368 RCX: ffff8880265bbc00 RDX: 0000000000010000 RSI: 0000000000000004 RDI: 0000000000000001 RBP: ffffc90000007ea0 R08: ffff8880b86276c3 R09: 1ffff110170c4ed8 R10: dffffc0000000000 R11: ffffed10170c4ed9 R12: 1ffff110170c4f03 R13: ffffffff8a1ecc60 R14: ffff888022353340 R15: ffff8880b86276c0 FS: 000055557cc38500(0000) GS:ffff888124fc9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffc9dfc5fb8 CR3: 0000000065eb8000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x110/0x420 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__kasan_check_byte+0x0/0x40 mm/kasan/common.c:555 Code: e6 fe ff ff 48 ff c8 48 89 c3 e9 db fe ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <66> 0f 1f 00 41 57 41 56 53 49 89 f6 49 89 ff e8 9c 17 00 00 89 c3 RSP: 0018:ffffc9000408f920 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffffff8ed3dfe0 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffffff823417c6 RDI: ffffffff8ed3dfe0 RBP: ffffffff93657020 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: fffffbfff20bd6cf R12: 0000000000000000 R13: 0000000000000002 R14: ffffffff823417a9 R15: 0000000000000000 kasan_check_byte include/linux/kasan.h:399 [inline] lock_acquire+0x89/0x2f0 kernel/locking/lockdep.c:5840 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] percpu_ref_put_many include/linux/percpu-refcount.h:330 [inline] percpu_ref_put+0x36/0x180 include/linux/percpu-refcount.h:351 obj_cgroup_put include/linux/memcontrol.h:772 [inline] __memcg_slab_free_hook+0xa7/0x310 mm/memcontrol.c:3106 memcg_slab_free_hook mm/slub.c:2214 [inline] slab_free mm/slub.c:4643 [inline] kfree+0x237/0x430 mm/slub.c:4845 simple_xattr_free fs/xattr.c:1214 [inline] simple_xattrs_free+0x122/0x160 fs/xattr.c:1550 shmem_evict_inode+0x87f/0xa80 mm/shmem.c:1386 evict+0x4f9/0x9b0 fs/inode.c:810 do_unlinkat+0x4a6/0x7b0 fs/namei.c:4615 __do_sys_unlink fs/namei.c:4654 [inline] __se_sys_unlink fs/namei.c:4652 [inline] __x64_sys_unlink+0x47/0x50 fs/namei.c:4652 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: 0033:0x7fda9058c717 Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 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:00007ffc9dfc6188 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fda9058c717 RDX: 00007ffc9dfc61b0 RSI: 00007ffc9dfc6240 RDI: 00007ffc9dfc6240 RBP: 00007ffc9dfc6240 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffc9dfc72d0 R13: 00007fda9060e08c R14: 00000000000c3d09 R15: 00007ffc9dfc7310