GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P12100/1:b..l P12104/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=86829, q=438 ncpus=1)
task:syz.0.1706 state:R running task stack:25928 pid:12104 tgid:12100 ppid:5611 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556
irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline]
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x205/0xa00 kernel/entry/common.c:167
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__sanitizer_cov_trace_pc+0x54/0x70 kernel/kcov.c:222
Code: c3 cc cc cc cc 8b 82 24 17 00 00 85 c0 74 f1 8b 82 f8 16 00 00 83 f8 02 75 e6 48 8b 8a 00 17 00 00 8b 92 fc 16 00 00 48 8b 01 <48> 83 c0 01 48 39 d0 73 cd 48 89 01 48 89 34 c1 c3 cc cc cc cc 0f
RSP: 0018:ffffc90003827ab8 EFLAGS: 00000246
RAX: 0000000000008635 RBX: ffffc90003827b40 RCX: ffffc9000eb02000
RDX: 0000000000080000 RSI: ffffffff81fc9528 RDI: ffff888037f2a540
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: fffff52000704f6e
R13: ffffc90003827b70 R14: 0000000000000000 R15: 0000000000000000
rcu_read_unlock include/linux/rcupdate.h:869 [inline]
class_rcu_destructor include/linux/rcupdate.h:1183 [inline]
futex_unqueue+0x108/0x2c0 kernel/futex/core.c:881
__futex_wait+0x1cc/0x300 kernel/futex/waitwake.c:725
futex_wait+0xe6/0x370 kernel/futex/waitwake.c:750
do_futex+0x265/0x440 kernel/futex/syscalls.c:133
__do_sys_futex kernel/futex/syscalls.c:210 [inline]
__se_sys_futex kernel/futex/syscalls.c:191 [inline]
__x64_sys_futex+0x34f/0x4d0 kernel/futex/syscalls.c:191
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f56e3b9de99
RSP: 002b:00007f56e1cf50e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f56e3e26098 RCX: 00007f56e3b9de99
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f56e3e26098
RBP: 00007f56e3e26090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f56e3e26128 R14: 00007ffe0c8c8300 R15: 00007ffe0c8c83e8
task:syz.0.1706 state:R running task stack:26984 pid:12100 tgid:12100 ppid:5611 task_flags:0x400040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556
irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline]
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x205/0xa00 kernel/entry/common.c:167
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:futex_unqueue+0x7e/0x2c0 kernel/futex/core.c:905
Code: c8 cb 0d 00 4c 8d 6b 30 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 80 3c 02 00 0f 85 15 02 00 00 4d 89 ec 48 8b 6b 30 <48> b8 00 00 00 00 00 fc ff df 49 c1 ec 03 49 01 c4 48 85 ed 0f 84
RSP: 0018:ffffc900038f7ac0 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: ffffc900038f7b40 RCX: ffffffff81fc957f
RDX: 1ffff9200071ef6e RSI: ffffffff81fc9478 RDI: ffff88802a3eca80
RBP: ffff88808458c648 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffc900038f7b70
R13: ffffc900038f7b70 R14: 0000000000000000 R15: 0000000000000000
__futex_wait+0x1cc/0x300 kernel/futex/waitwake.c:725
futex_wait+0xe6/0x370 kernel/futex/waitwake.c:750
do_futex+0x265/0x440 kernel/futex/syscalls.c:133
__do_sys_futex kernel/futex/syscalls.c:210 [inline]
__se_sys_futex kernel/futex/syscalls.c:191 [inline]
__x64_sys_futex+0x34f/0x4d0 kernel/futex/syscalls.c:191
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f56e3b9de99
RSP: 002b:00007ffe0c8c8548 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00000000000764c9 RCX: 00007f56e3b9de99
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f56e3e2609c
RBP: 0000000000000032 R08: 0000000000000001 R09: 0000000000000000
R10: 00007ffe0c8c8650 R11: 0000000000000246 R12: 00007ffe0c8c8670
R13: 00007f56e3e2609c R14: 00000000000764fb R15: 00007ffe0c8c8650
rcu: rcu_preempt kthread starved for 9980 jiffies! g86829 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:27592 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556
irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline]
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x205/0xa00 kernel/entry/common.c:167
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:free_object lib/debugobjects.c:550 [inline]
RIP: 0010:debug_object_free+0x2aa/0x550 lib/debugobjects.c:1039
Code: 48 83 c0 22 48 89 43 08 e8 c3 04 96 06 48 89 df e8 db d0 ff ff 0f b6 05 54 58 65 16 84 c0 0f 85 12 fe ff ff 8b 05 0e e0 58 0a <85> c0 0f 84 04 fe ff ff 48 c7 c0 08 e1 46 8e c6 05 30 58 65 16 01
RSP: 0018:ffffc90000157ab0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff8880820bf230 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8e1a5f23 RDI: ffffffff8c401680
RBP: ffffc90000157ba0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff9b9dab50 R14: ffffc90000157bd0 R15: 1ffff9200002af5a
schedule_timeout+0x137/0x280 kernel/time/sleep_timeout.c:103
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
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: 12103 Comm: syz.4.1707 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:x64_setup_rt_frame+0x8e3/0xce0 arch/x86/kernel/signal_64.c:210
Code: ea 03 80 3c 02 00 0f 85 d1 03 00 00 48 8b 44 24 10 4c 89 ea 48 c1 ea 03 48 89 43 60 48 b8 00 00 00 00 00 fc ff df 80 3c 02 00 <0f> 85 a0 03 00 00 48 8b 54 24 40 4d 8b 6d 00 48 b8 00 00 00 00 00
RSP: 0018:ffffc90003907cd0 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: ffffc90003907f48 RCX: ffffc900072b9000
RDX: 1ffff92000720fbd RSI: ffffffff81aade83 RDI: ffffc90003907e38
RBP: 00007f60a51f53f8 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffffc90003907de8 R14: ffffc90003907fb8 R15: 00007f60a51f5530
FS: 00007f60a51f66c0(0000) GS:ffff888123ddc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 00000000572e7000 CR4: 00000000003526f0
Call Trace:
setup_rt_frame arch/x86/kernel/signal.c:250 [inline]
handle_signal arch/x86/kernel/signal.c:294 [inline]
arch_do_signal_or_restart+0x5ee/0x7e0 arch/x86/kernel/signal.c:339
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x139/0x6f0 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x666/0x870 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f60a6f9de97
Code: 83 c8 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
RSP: 002b:00007f60a51f60e8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f60a7225fa8 RCX: 00007f60a6f9de99
RDX: 00007f60a51f5400 RSI: 00007f60a51f5530 RDI: 0000000000000021
RBP: 00007f60a7225fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f60a7226038 R14: 00007ffe36ec30c0 R15: 00007ffe36ec31a8
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog