rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9264/1:b..l rcu: (detected by 1, t=10503 jiffies, g=38949, q=830907 ncpus=2) task:syz.1.881 state:R running task stack:23168 pid:9264 tgid:9261 ppid:6895 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5315 [inline] __schedule+0x1895/0x4b30 kernel/sched/core.c:6675 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:6997 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x264/0x550 kernel/locking/lockdep.c:5826 Code: 2b 00 74 08 4c 89 f7 e8 9a 4f 8e 00 f6 44 24 61 02 0f 85 85 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc900099e6ce0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff9200133cda8 RCX: 7b8e10b2f528e100 RDX: dffffc0000000000 RSI: ffffffff8c0adbc0 RDI: ffffffff8c6100e0 RBP: ffffc900099e6e28 R08: ffffffff9426e7c7 R09: 1ffffffff284dcf8 R10: dffffc0000000000 R11: fffffbfff284dcf9 R12: 1ffff9200133cda4 R13: dffffc0000000000 R14: ffffc900099e6d40 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:337 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] blk_cgroup_congested+0x38/0x200 block/blk-cgroup.c:2191 __folio_throttle_swaprate+0x84/0x1d0 mm/swapfile.c:3990 folio_throttle_swaprate include/linux/swap.h:645 [inline] shmem_add_to_page_cache+0x816/0x1690 mm/shmem.c:801 shmem_alloc_and_add_folio+0x96a/0x13d0 mm/shmem.c:1839 shmem_get_folio_gfp+0x5a9/0x20a0 mm/shmem.c:2335 shmem_fault+0x253/0x6f0 mm/shmem.c:2536 __do_fault+0x135/0x460 mm/memory.c:4876 do_read_fault mm/memory.c:5282 [inline] do_fault mm/memory.c:5416 [inline] do_pte_missing mm/memory.c:3965 [inline] handle_pte_fault+0x2d1c/0x6800 mm/memory.c:5751 __handle_mm_fault mm/memory.c:5894 [inline] handle_mm_fault+0x1106/0x1bb0 mm/memory.c:6062 faultin_page mm/gup.c:1187 [inline] __get_user_pages+0x1b16/0x48d0 mm/gup.c:1485 populate_vma_page_range+0x264/0x330 mm/gup.c:1923 __mm_populate+0x27a/0x460 mm/gup.c:2026 mm_populate include/linux/mm.h:3371 [inline] vm_mmap_pgoff+0x2c3/0x3d0 mm/util.c:593 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f907b77dff9 RSP: 002b:00007f907c490038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f907b936058 RCX: 00007f907b77dff9 RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000000020000000 RBP: 00007f907b7f0296 R08: ffffffffffffffff R09: 0000000000001000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f907b936058 R15: 00007ffe1ac64b88 rcu: rcu_preempt kthread starved for 10470 jiffies! g38949 f0x2 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:25888 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5315 [inline] __schedule+0x1895/0x4b30 kernel/sched/core.c:6675 __schedule_loop kernel/sched/core.c:6752 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6767 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2615 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 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: 5310 Comm: kworker/0:5 Not tainted 6.11.0-syzkaller-11517-g7c2f1c2690a5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: events nsim_dev_trap_report_work RIP: 0010:get_current arch/x86/include/asm/current.h:49 [inline] RIP: 0010:write_comp_data kernel/kcov.c:245 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x8/0x90 kernel/kcov.c:300 Code: cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 4c 8b 04 24 <65> 48 8b 14 25 c0 d7 03 00 65 8b 05 70 1f 6f 7e 25 00 01 ff 00 74 RSP: 0018:ffffc900000077f0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88807b133c00 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffffff8a986cf0 R08: ffffffff8a986d3b R09: 0000000000000000 R10: ffffc900000078f0 R11: ffffffff8a986cf0 R12: dffffc0000000000 R13: ffffc900000078e0 R14: ffff88805f69b710 R15: ffff888233a9c500 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30b0fff8 CR3: 000000000e734000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: skb_ext_exist include/linux/skbuff.h:4837 [inline] skb_ext_find include/linux/skbuff.h:4848 [inline] nf_bridge_info_get include/linux/netfilter_bridge.h:30 [inline] ip_sabotage_in+0x4b/0x290 net/bridge/br_netfilter_hooks.c:1003 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK+0x29e/0x450 include/linux/netfilter.h:312 __netif_receive_skb_one_core net/core/dev.c:5662 [inline] __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5775 process_backlog+0x662/0x15b0 net/core/dev.c:6107 __napi_poll+0xcb/0x490 net/core/dev.c:6771 napi_poll net/core/dev.c:6840 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:6962 handle_softirqs+0x2c5/0x980 kernel/softirq.c:554 do_softirq+0x11b/0x1e0 kernel/softirq.c:455 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382 spin_unlock_bh include/linux/spinlock.h:396 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:820 [inline] nsim_dev_trap_report_work+0x75d/0xaa0 drivers/net/netdevsim/dev.c:850 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244