rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (2 GPs behind) idle=6fa4/1/0x4000000000000000 softirq=19668/19674 fqs=61 rcu: (detected by 0, t=10502 jiffies, g=12765, q=725 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6199 Comm: cmp Not tainted 6.15.0-rc5-syzkaller-00300-g3ce9925823c7 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:memset+0xf/0x20 arch/x86/lib/memset_64.S:38 Code: 44 88 1f e9 4e 04 ba f5 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 49 89 f9 40 88 f0 48 89 d1 aa 4c 89 c8 e9 22 04 ba f5 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000a08c80 EFLAGS: 00000002 RAX: 00e7bcbba9fc6f00 RBX: ffff888032e9a340 RCX: 000000000000000f RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc90000a08ca1 RBP: 0000000000000000 R08: ffffc90000a08caf R09: ffffc90000a08ca0 R10: dffffc0000000000 R11: fffff52000141196 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffffff8b6cd600 R15: ffff8880b8927740 FS: 0000000000000000(0000) GS:ffff8881261cb000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5489e764ac CR3: 00000000480c2000 CR4: 0000000000350ef0 Call Trace: debug_object_activate+0x38/0x420 lib/debugobjects.c:806 debug_hrtimer_activate kernel/time/hrtimer.c:445 [inline] debug_activate kernel/time/hrtimer.c:484 [inline] enqueue_hrtimer+0x30/0x3a0 kernel/time/hrtimer.c:1088 __run_hrtimer kernel/time/hrtimer.c:1778 [inline] __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x10b/0x410 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:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5870 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 8b 31 d7 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc900048ef600 EFLAGS: 00000206 RAX: 00e7bcbba9fc6f00 RBX: 0000000000000000 RCX: 00e7bcbba9fc6f00 RDX: 0000000000000001 RSI: ffffffff8d935d61 RDI: ffffffff8bc1d2e0 RBP: ffffffff81f7b474 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff81f7b474 R12: 0000000000000002 R13: ffffffff8df3b860 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] filemap_get_read_batch+0xe1/0x7b0 mm/filemap.c:2361 filemap_get_pages+0x2eb/0x1eb0 mm/filemap.c:2581 filemap_read+0x3fa/0x11d0 mm/filemap.c:2702 new_sync_read fs/read_write.c:489 [inline] vfs_read+0x4d0/0x980 fs/read_write.c:570 ksys_read+0x145/0x250 fs/read_write.c:713 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f548a120134 Code: 48 3d 00 f0 ff ff 77 06 c3 0f 1f 44 00 00 f7 d8 89 05 80 41 01 00 48 c7 c0 ff ff ff ff c3 0f 1f 84 00 00 00 00 00 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 04 c3 0f 1f 00 f7 d8 89 05 58 41 01 00 48 c7 RSP: 002b:00007fff99fa94a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007fff99fa9520 RCX: 00007f548a120134 RDX: 0000000000000340 RSI: 00007fff99fa9738 RDI: 0000000000000003 RBP: 00007fff99fa9510 R08: 00007fff99fa9717 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000340 R14: 00007fff99fa9730 R15: 00007fff99fa9738 rcu: rcu_preempt kthread starved for 10197 jiffies! g12765 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:27304 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2248 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4e/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: CPU: 0 UID: 0 PID: 6143 Comm: udevd Not tainted 6.15.0-rc5-syzkaller-00300-g3ce9925823c7 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x70 kernel/kcov.c:216 Code: 8b 3d 1c 24 d7 0b 48 89 de 5b e9 a3 62 57 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0c 25 08 50 75 92 65 8b 15 e8 7f b5 10 81 e2 00 01 ff 00 RSP: 0000:ffffc9000482f718 EFLAGS: 00000202 RAX: ffffffff81b46780 RBX: ffff8880b883ad40 RCX: ffff8880261b8000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000482f880 R08: ffffffff8f7ed377 R09: 1ffffffff1efda6e R10: dffffc0000000000 R11: fffffbfff1efda6f R12: 1ffff11017127e99 R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880b893f4c8 FS: 00007f7b5c163880(0000) GS:ffff8881260cb000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000564dc7d100e8 CR3: 000000007aed1000 CR4: 0000000000350ef0 Call Trace: csd_lock_wait kernel/smp.c:340 [inline] smp_call_function_many_cond+0xe80/0x11c0 kernel/smp.c:885 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1291 [inline] flush_tlb_mm_range+0x6ae/0x12b0 arch/x86/mm/tlb.c:1381 flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline] ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:101 wp_page_copy mm/memory.c:3544 [inline] do_wp_page+0x1b5e/0x5760 mm/memory.c:3939 handle_pte_fault mm/memory.c:6013 [inline] __handle_mm_fault+0x1028/0x5380 mm/memory.c:6140 handle_mm_fault+0x3f6/0x8c0 mm/memory.c:6309 do_user_addr_fault+0xa81/0x1390 arch/x86/mm/fault.c:1337 handle_page_fault arch/x86/mm/fault.c:1480 [inline] exc_page_fault+0x68/0x110 arch/x86/mm/fault.c:1538 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:0x7f7b5bab5b69 Code: 10 48 81 f9 ff 03 00 00 76 28 48 8b 57 20 48 85 d2 74 1f 48 3b 7a 28 75 76 48 8b 4f 28 48 3b 79 20 75 6c 48 83 78 20 00 74 17 <48> 89 4a 28 48 89 51 20 48 83 c4 08 c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffe43a83fa0 EFLAGS: 00010206 RAX: 00007f7b5bbf20e0 RBX: 0000564dc7d100c0 RCX: 0000564dc7d100c0 RDX: 0000564dc7d100c0 RSI: 00007f7b5bbf20e0 RDI: 0000564dc7d100c0 RBP: 00007f7b5bbf1ac0 R08: 0000000000002760 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000032b0 R13: 0000564dc7d13370 R14: 0000000000004180 R15: 00007f7b5bbf1ac0