rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (0 ticks this GP) idle=c93c/1/0x4000000000000000 softirq=19080/19082 fqs=293
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6585/1:b..l
(detected by 1, t=10506 jiffies, g=25045, q=913 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6573 Comm: syz.2.608 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:asm_sysvec_irq_work+0x0/0x20 arch/x86/include/asm/idtentry.h:722
Code: e9 b5 03 00 00 90 90 90 90 90 0f 01 ca fc 6a ff e8 b5 02 00 00 48 89 c4 48 89 e7 e8 1a 9d d7 ff e9 95 03 00 00 90 90 90 90 90 <0f> 01 ca fc 6a ff e8 95 02 00 00 48 89 c4 48 89 e7 e8 ea a1 d7 ff
RSP: 0018:ffffc9000c6f7298 EFLAGS: 00000006
RAX: bbfbd1b38bb33000 RBX: 1ffff920018dee60 RCX: bbfbd1b38bb33000
RDX: dffffc0000000000 RSI: ffffffff8a8c0580 RDI: ffffffff8adef760
RBP: ffffc9000c6f73b8 R08: dffffc0000000000 R09: fffffbfff215c449
R10: fffffbfff215c449 R11: 1ffffffff215c448 R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8e3b900 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000007d2000 CR3: 000000002682f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
RIP: 0010:rcu_read_unlock_special+0x84/0x500 kernel/rcu/tree_plugin.h:685
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 ed 90 96 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc9000c6f72c0 EFLAGS: 00000206
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
rcu_read_unlock include/linux/rcupdate.h:823 [inline]
__folio_memcg_unlock+0xea/0x110 mm/memcontrol.c:2151
page_remove_rmap+0x7e3/0xea0 mm/rmap.c:1462
zap_pte_range mm/memory.c:1453 [inline]
zap_pmd_range mm/memory.c:1574 [inline]
zap_pud_range mm/memory.c:1603 [inline]
zap_p4d_range mm/memory.c:1624 [inline]
unmap_page_range+0x1149/0x2500 mm/memory.c:1645
unmap_vmas+0x22c/0x330 mm/memory.c:1730
exit_mmap+0x1cc/0x8e0 mm/mmap.c:3250
__mmput+0x118/0x3c0 kernel/fork.c:1200
exit_mm+0x1e6/0x2c0 kernel/exit.c:565
do_exit+0x8c1/0x2400 kernel/exit.c:867
do_group_exit+0x217/0x2d0 kernel/exit.c:1022
get_signal+0x1272/0x1350 kernel/signal.c:2871
arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f378c38efc9
Code: Unable to access opcode bytes at 0x7f378c38ef9f.
RSP: 002b:00007f378d2e50e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f378c5e5fa8 RCX: 00007f378c38efc9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f378c5e5fa8
RBP: 00007f378c5e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f378c5e6038 R14: 00007fff32a1b100 R15: 00007fff32a1b1e8
task:syz.4.611 state:R running task stack:23424 pid:6585 ppid:4271 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
irqentry_exit+0x63/0x70 kernel/entry/common.c:439
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:check_kcov_mode kernel/kcov.c:193 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x32/0x60 kernel/kcov.c:216
Code: d4 98 81 7e 65 8b 15 d5 98 81 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 f8 15 00 00 <83> fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48 8d 7e 01 8b 89 fc
RSP: 0018:ffffc9000cf07a68 EFLAGS: 00000246
RAX: ffffffff882c6342 RBX: 00000000fffffffe RCX: ffff88802658d940
RDX: 0000000000000002 RSI: 00000000fffffffe RDI: 0000000000000000
RBP: 0000000000000080 R08: dffffc0000000000 R09: ffffed1004cb1b29
R10: ffffed1004cb1b29 R11: 1ffff11004cb1b28 R12: dffffc0000000000
R13: ffffc9000cf29030 R14: ffff888023b03488 R15: ffff888054b5d000
cgroup_ancestor include/linux/cgroup.h:608 [inline]
__bpf_sk_ancestor_cgroup_id net/core/filter.c:4898 [inline]
____bpf_skb_ancestor_cgroup_id net/core/filter.c:4908 [inline]
bpf_skb_ancestor_cgroup_id+0x172/0x270 net/core/filter.c:4905
bpf_prog_ec1855f5d9fcb393+0x1d/0x41
bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline]
__bpf_prog_run include/linux/filter.h:603 [inline]
bpf_prog_run include/linux/filter.h:610 [inline]
bpf_test_run+0x29e/0x7d0 net/bpf/test_run.c:402
bpf_prog_test_run_skb+0xa40/0x11b0 net/bpf/test_run.c:1183
bpf_prog_test_run+0x31e/0x390 kernel/bpf/syscall.c:3692
__sys_bpf+0x593/0x6d0 kernel/bpf/syscall.c:5045
__do_sys_bpf kernel/bpf/syscall.c:5131 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5129 [inline]
__x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5129
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f2953b8efc9
RSP: 002b:00007f29549c1038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f2953de5fa0 RCX: 00007f2953b8efc9
RDX: 0000000000000050 RSI: 00002000000005c0 RDI: 000000000000000a
RBP: 00007f2953c11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2953de6038 R14: 00007f2953de5fa0 R15: 00007fffe60960d8
rcu: rcu_preempt kthread starved for 9040 jiffies! g25045 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:26880 pid:16 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
schedule_timeout+0x15c/0x280 kernel/time/timer.c:2167
rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 9 Comm: kworker/u4:0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:kvm_wait+0x141/0x190 arch/x86/kernel/kvm.c:1064
Code: 89 df 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 47 0f b6 1f e8 0f 41 4f 00 44 38 e3 75 10 66 90 0f 00 2d 51 74 51 09 fb f4 33 ff ff ff fb e9 2d ff ff ff e8 6f e0 df 08 89 f9 80 e1 07 38
RSP: 0018:ffffc900000e6460 EFLAGS: 00000246
RAX: 07dca16e5d1a4e00 RBX: 0000000000000003 RCX: 07dca16e5d1a4e00
RDX: dffffc0000000000 RSI: ffffffff8a8c0580 RDI: ffffffff8adef760
RBP: ffffc900000e6510 R08: dffffc0000000000 R09: fffffbfff215c449
R10: fffffbfff215c449 R11: 1ffffffff215c448 R12: 0000000000000003
R13: ffff8880b8f3b914 R14: dffffc0000000000 R15: 1ffff9200001cc8c
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7ebd7f6d00 CR3: 000000000c88e000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
pv_wait arch/x86/include/asm/paravirt.h:603 [inline]
pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
__pv_queued_spin_lock_slowpath+0x616/0x9c0 kernel/locking/qspinlock.c:511
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline]
queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51
queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
do_raw_spin_lock+0x217/0x280 kernel/locking/spinlock_debug.c:115
page_vma_mapped_walk+0x1437/0x1720 mm/page_vma_mapped.c:-1
page_vma_mkclean_one+0x350/0x680 mm/rmap.c:958
page_mkclean_one+0x1d6/0x370 mm/rmap.c:1018
rmap_walk_file+0x3e8/0x730 mm/rmap.c:2511
rmap_walk mm/rmap.c:2529 [inline]
folio_mkclean+0x1c4/0x330 mm/rmap.c:1050
folio_clear_dirty_for_io+0x20a/0xc30 mm/page-writeback.c:2886
mpage_submit_page+0x8a/0x210 fs/ext4/inode.c:2122
mpage_process_page_bufs+0x6d8/0x8b0 fs/ext4/inode.c:2256
mpage_prepare_extent_to_map+0xaf4/0x15d0 fs/ext4/inode.c:2681
ext4_writepages+0xa22/0x2e50 fs/ext4/inode.c:2809
do_writepages+0x3b7/0x610 mm/page-writeback.c:2491
__writeback_single_inode+0x156/0x1160 fs/fs-writeback.c:1622
writeback_sb_inodes+0xad8/0x17d0 fs/fs-writeback.c:1913
__writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:1984
wb_writeback+0x47a/0xd00 fs/fs-writeback.c:2089
wb_check_old_data_flush fs/fs-writeback.c:2189 [inline]
wb_do_writeback fs/fs-writeback.c:2242 [inline]
wb_workfn+0xb66/0xec0 fs/fs-writeback.c:2270
process_one_work+0x898/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295