GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (3 ticks this GP) idle=d464/1/0x4000000000000000 softirq=21360/21360 fqs=0
rcu: 	(detected by 1, t=10505 jiffies, g=13129, q=1489 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 6733 Comm: syz.0.178 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:rb_next+0x44/0x130 lib/rbtree.c:503
Code: 89 fb 48 83 ec 08 80 3c 02 00 0f 85 f8 00 00 00 48 8b 2b 48 39 eb 0f 84 ae 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 08 <48> 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 c3 00 00 00 49 bc 00 00 00
RSP: 0018:ffffc90000007db8 EFLAGS: 00000096
RAX: dffffc0000000000 RBX: ffff88802954d340 RCX: ffffffff8b911d20
RDX: 1ffff110052a9a68 RSI: ffffffff8b911db0 RDI: ffff88802954d348
RBP: 0000000000000001 R08: 0000000000000006 R09: 0000000000000001
R10: ffff88802954d340 R11: 0000000000000000 R12: ffff8880b8427e58
R13: 0000000000000000 R14: ffff8880b8427c80 R15: 0000000000000000
FS:  00007fe008eb66c0(0000) GS:ffff8881246b1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000288000 CR3: 00000000767e5000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 rb_erase_cached include/linux/rbtree.h:124 [inline]
 timerqueue_del+0xd8/0x150 lib/timerqueue.c:57
 __remove_hrtimer+0x99/0x290 kernel/time/hrtimer.c:1121
 __run_hrtimer kernel/time/hrtimer.c:1741 [inline]
 __hrtimer_run_queues+0x4f9/0xad0 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:do_user_addr_fault+0x198/0x1370 arch/x86/mm/fault.c:1291
Code: 31 ff 41 81 e5 00 02 00 00 4c 89 ee e8 21 70 4f 00 4d 85 ed 0f 84 3d 09 00 00 e8 a3 74 4f 00 e8 7e 5b 57 00 fb 0f 1f 44 00 00 <e8> 93 74 4f 00 48 89 d8 31 ff 41 bd 14 02 00 00 83 e0 40 49 89 c7
RSP: 0018:ffffc9000fe37908 EFLAGS: 00000202
RAX: 000000000001b8e9 RBX: 0000000000000000 RCX: ffffffff81c380af
RDX: 0000000000000000 RSI: ffffffff8de52fc1 RDI: ffffffff8c163380
RBP: ffffc9000fe379a8 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff90ab7697 R11: 0000000000000000 R12: 0000200000288000
R13: 0000000000000200 R14: ffff88807c23ab00 R15: 0000000000000000
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x5c/0xb0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:rep_movs_alternative+0x30/0x90 arch/x86/lib/copy_user_64.S:60
Code: 83 f9 08 73 25 85 c9 74 0f 8a 06 88 07 48 ff c7 48 ff c6 48 ff c9 75 f1 c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 <48> 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 db 83 f9 08
RSP: 0018:ffffc9000fe37a58 EFLAGS: 00050206
RAX: 0000000000000001 RBX: 0000200000288000 RCX: 0000000000000038
RDX: fffff52001fc6f5c RSI: 0000200000288000 RDI: ffffc9000fe37aa8
RBP: 0000000000000038 R08: 0000000000000001 R09: fffff52001fc6f5b
R10: ffffc9000fe37adf R11: 0000000000000000 R12: 0000000000000000
R13: ffffc9000fe37aa8 R14: ffffc9000fe37b90 R15: ffffc9000fe37aa8
 copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline]
 raw_copy_from_user arch/x86/include/asm/uaccess_64.h:141 [inline]
 _inline_copy_from_user include/linux/uaccess.h:178 [inline]
 _copy_from_user+0x98/0xd0 lib/usercopy.c:18
 copy_from_user include/linux/uaccess.h:212 [inline]
 copy_msghdr_from_user+0x98/0x160 net/socket.c:2544
 recvmsg_copy_msghdr net/socket.c:2800 [inline]
 ___sys_recvmsg+0xdb/0x1a0 net/socket.c:2872
 do_recvmmsg+0x2fe/0x750 net/socket.c:2971
 __sys_recvmmsg net/socket.c:3045 [inline]
 __do_sys_recvmmsg net/socket.c:3068 [inline]
 __se_sys_recvmmsg net/socket.c:3061 [inline]
 __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3061
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe007f8eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe008eb6038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007fe0081e6090 RCX: 00007fe007f8eec9
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000004
RBP: 00007fe008011f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe0081e6128 R14: 00007fe0081e6090 R15: 00007fff6b858f48
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10504 jiffies! g13129 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=7736
rcu: rcu_preempt kthread starved for 10505 jiffies! g13129 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:27784 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c2/0x780 kernel/kthread.c:463
 ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>