rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=d21/1/0x4000000000000002 softirq=18346/18346 fqs=0 (detected by 1, t=10502 jiffies, g=22557, q=2935) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 8630 Comm: syz.2.1326 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:task_irq_context kernel/locking/lockdep.c:4520 [inline] RIP: 0010:__lock_acquire+0x446/0x7d10 kernel/locking/lockdep.c:4950 Code: df e8 ee 39 61 00 49 b8 00 00 00 00 00 fc ff df 48 89 9c 24 a8 00 00 00 48 8b 45 10 48 89 03 65 8b 05 e2 5a a5 7e 31 db 85 c0 <0f> 95 c3 01 db 48 8b 44 24 30 4c 8d a0 d4 0a 00 00 4c 89 e0 48 c1 RSP: 0018:ffffc9000319eae0 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1ffff110045b816c RDX: 0000000000000015 RSI: 0000000000000000 RDI: ffff888022dc0b50 RBP: ffffc9000319ed30 R08: dffffc0000000000 R09: 0000000000000001 R10: dffffc0000000000 R11: fffffbfff1b13f06 R12: ffff888022dc0b40 R13: 0000000000000000 R14: 0000000000000015 R15: ffff888022dc0b40 FS: 00007fc5568f86c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc5568d7d58 CR3: 000000007b747000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313 rcu_read_lock include/linux/rcupdate.h:740 [inline] __perf_event_output kernel/events/core.c:7800 [inline] perf_event_output_forward+0xbc/0x2e0 kernel/events/core.c:7822 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515 perf_swevent_overflow kernel/events/core.c:9591 [inline] perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629 perf_tp_event+0x383/0xbf0 kernel/events/core.c:10047 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674 Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 d2 df 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08 RSP: 0018:ffffc9000319f520 EFLAGS: 00000206 RAX: f83f3b0e46b3e300 RBX: 1ffff92000633ea8 RCX: f83f3b0e46b3e300 RDX: dffffc0000000000 RSI: ffffffff8a2b3100 RDI: ffffffff8a7a0700 RBP: ffffc9000319f600 R08: ffff8880b903b30b R09: 1ffff11017207661 R10: dffffc0000000000 R11: ffffed1017207662 R12: ffffffff8c323800 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] mod_objcg_mlstate+0x23b/0x2e0 mm/memcontrol.c:832 drain_obj_stock+0x1ec/0x370 mm/memcontrol.c:3203 refill_obj_stock+0x11d/0x470 mm/memcontrol.c:3242 memcg_slab_free_hook+0x157/0x1f0 mm/slab.h:364 do_slab_free mm/slub.c:3437 [inline] ___cache_free+0x63/0x120 mm/slub.c:3511 qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283 __kasan_slab_alloc+0x2f/0xd0 mm/kasan/common.c:444 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519 slab_alloc_node mm/slub.c:3225 [inline] slab_alloc mm/slub.c:3233 [inline] kmem_cache_alloc+0x100/0x290 mm/slub.c:3238 __d_alloc+0x2a/0x6f0 fs/dcache.c:1749 d_alloc_pseudo+0x19/0x70 fs/dcache.c:1880 alloc_file_pseudo+0xe0/0x200 fs/file_table.c:256 __anon_inode_getfile fs/anon_inodes.c:109 [inline] anon_inode_getfile+0xc1/0x1a0 fs/anon_inodes.c:147 __do_sys_perf_event_open kernel/events/core.c:12613 [inline] __se_sys_perf_event_open+0xc02/0x1bb0 kernel/events/core.c:12387 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fc5586bfe59 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:00007fc5568f8028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007fc558939090 RCX: 00007fc5586bfe59 RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 00002000000000c0 RBP: 00007fc558755d6f R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc558939128 R14: 00007fc558939090 R15: 00007ffc423d13b8 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g22557 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=9303 rcu: rcu_preempt kthread starved for 10502 jiffies! g22557 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:27800 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 8630 Comm: syz.2.1326 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:constant_test_bit arch/x86/include/asm/bitops.h:207 [inline] RIP: 0010:arch_irq_work_has_interrupt arch/x86/include/asm/irq_work.h:10 [inline] RIP: 0010:arch_irq_work_raise+0x1d/0xd0 arch/x86/kernel/irq_work.c:28 Code: c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 41 56 53 49 be 00 00 00 00 00 fc ff df 48 c7 c0 50 f0 89 8d 48 c1 e8 03 42 80 3c 30 00 <74> 0c 48 c7 c7 50 f0 89 8d e8 05 8c 93 00 48 f7 05 6a 27 5f 0c 00 RSP: 0018:ffffc9000319ed30 EFLAGS: 00000046 RAX: 1ffffffff1b13e0a RBX: ffff8880b903b1f0 RCX: ffff888022dc0000 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff8880b9033d70 RBP: 0000000000000000 R08: ffff8880b9033d77 R09: 1ffff110172067ae R10: dffffc0000000000 R11: ffffed10172067af R12: 0000000000000000 R13: dffffc0000000001 R14: dffffc0000000000 R15: 0000000000000000 FS: 00007fc5568f86c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc5568d7d58 CR3: 000000007b747000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: irq_work_queue_on+0x11e/0x220 kernel/irq_work.c:109 rcu_read_unlock_special+0x37b/0x4a0 kernel/rcu/tree_plugin.h:667 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] __perf_event_output kernel/events/core.c:7813 [inline] perf_event_output_forward+0x255/0x2e0 kernel/events/core.c:7822 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515 perf_swevent_overflow kernel/events/core.c:9591 [inline] perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629 perf_tp_event+0x383/0xbf0 kernel/events/core.c:10047 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674 Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 d2 df 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08 RSP: 0018:ffffc9000319f520 EFLAGS: 00000206 RAX: f83f3b0e46b3e300 RBX: 1ffff92000633ea8 RCX: f83f3b0e46b3e300 RDX: dffffc0000000000 RSI: ffffffff8a2b3100 RDI: ffffffff8a7a0700 RBP: ffffc9000319f600 R08: ffff8880b903b30b R09: 1ffff11017207661 R10: dffffc0000000000 R11: ffffed1017207662 R12: ffffffff8c323800 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] mod_objcg_mlstate+0x23b/0x2e0 mm/memcontrol.c:832 drain_obj_stock+0x1ec/0x370 mm/memcontrol.c:3203 refill_obj_stock+0x11d/0x470 mm/memcontrol.c:3242 memcg_slab_free_hook+0x157/0x1f0 mm/slab.h:364 do_slab_free mm/slub.c:3437 [inline] ___cache_free+0x63/0x120 mm/slub.c:3511 qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283 __kasan_slab_alloc+0x2f/0xd0 mm/kasan/common.c:444 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519 slab_alloc_node mm/slub.c:3225 [inline] slab_alloc mm/slub.c:3233 [inline] kmem_cache_alloc+0x100/0x290 mm/slub.c:3238 __d_alloc+0x2a/0x6f0 fs/dcache.c:1749 d_alloc_pseudo+0x19/0x70 fs/dcache.c:1880 alloc_file_pseudo+0xe0/0x200 fs/file_table.c:256 __anon_inode_getfile fs/anon_inodes.c:109 [inline] anon_inode_getfile+0xc1/0x1a0 fs/anon_inodes.c:147 __do_sys_perf_event_open kernel/events/core.c:12613 [inline] __se_sys_perf_event_open+0xc02/0x1bb0 kernel/events/core.c:12387 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fc5586bfe59 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:00007fc5568f8028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007fc558939090 RCX: 00007fc5586bfe59 RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 00002000000000c0 RBP: 00007fc558755d6f R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc558939128 R14: 00007fc558939090 R15: 00007ffc423d13b8