GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 ticks this GP) idle=a274/1/0x4000000000000000 softirq=70843/70843 fqs=1
rcu: (detected by 0, t=10502 jiffies, g=88969, q=421 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 15759 Comm: syz.1.2820 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:enqueue_hrtimer+0x88/0x2c0 kernel/time/hrtimer.c:1107
Code: 74 08 48 89 df e8 b8 3b 7e 00 48 8b 3b 48 83 c7 18 be ff ff ff ff e8 f7 00 f6 09 41 89 c4 31 ff 89 c6 e8 3b 02 13 00 45 85 e4 <0f> 84 6c 01 00 00 e8 ed fd 12 00 eb 05 e8 e6 fd 12 00 4c 89 f7 48
RSP: 0018:ffffc90000a08da0 EFLAGS: 00000002
RAX: ffffffff81b2c665 RBX: ffff8880b87283c0 RCX: 0000000000010000
RDX: ffff88807a099ec0 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520001411ac R12: 0000000000000001
R13: dffffc0000000000 R14: ffff888074817300 R15: 0000000000000000
FS: 00007f77355716c0(0000) GS:ffff88812538a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b34420ff8 CR3: 00000000357a4000 CR4: 0000000000350ef0
Call Trace:
__run_hrtimer kernel/time/hrtimer.c:1946 [inline]
__hrtimer_run_queues+0x4d2/0xa20 kernel/time/hrtimer.c:1994
hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
__sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:const_folio_flags include/linux/page-flags.h:345 [inline]
RIP: 0010:folio_test_head include/linux/page-flags.h:843 [inline]
RIP: 0010:folio_test_large include/linux/page-flags.h:864 [inline]
RIP: 0010:folio_order include/linux/mm.h:1724 [inline]
RIP: 0010:shmem_add_to_page_cache+0x36c/0xd40 mm/shmem.c:885
Code: df 48 8b 4c 24 20 80 3c 01 00 74 08 4c 89 ef e8 aa b6 23 00 49 8b 5d 00 48 89 de 48 83 e6 01 31 ff e8 d8 7d b8 ff 48 83 e3 01 <0f> 85 02 09 00 00 4c 89 e7 be 08 00 00 00 e8 f1 b8 23 00 48 b8 00
RSP: 0018:ffffc9000e9af380 EFLAGS: 00000246
RAX: ffffffff820d4b68 RBX: 0000000000000000 RCX: ffff88807a099ec0
RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000e9af4d0 R08: ffffea0001491047 R09: 1ffffd4000292208
R10: dffffc0000000000 R11: fffff94000292209 R12: ffffea0001491040
R13: ffffea0001491048 R14: dffffc0000000000 R15: 0000000000000000
shmem_alloc_and_add_folio+0x866/0xf80 mm/shmem.c:2001
shmem_get_folio_gfp+0x5a9/0x1670 mm/shmem.c:2564
shmem_fault+0x179/0x390 mm/shmem.c:2765
__do_fault+0x138/0x2a0 mm/memory.c:5458
do_read_fault mm/memory.c:5893 [inline]
do_fault mm/memory.c:6027 [inline]
do_pte_missing+0x2093/0x33f0 mm/memory.c:4550
handle_pte_fault mm/memory.c:6411 [inline]
__handle_mm_fault mm/memory.c:6549 [inline]
handle_mm_fault+0x1bd9/0x3170 mm/memory.c:6718
faultin_page mm/gup.c:1126 [inline]
__get_user_pages+0x1683/0x2720 mm/gup.c:1428
populate_vma_page_range+0x2be/0x3c0 mm/gup.c:1860
__mm_populate+0x25f/0x390 mm/gup.c:1963
mm_populate include/linux/mm.h:4137 [inline]
vm_mmap_pgoff+0x3aa/0x4f0 mm/util.c:586
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f773479ce59
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:00007f7735571028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f7734a15fa0 RCX: 00007f773479ce59
RDX: b635773f06ebbeef RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007f7734832d6f R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7734a16038 R14: 00007f7734a15fa0 R15: 00007ffe8b5c2fb8
rcu: rcu_preempt kthread starved for 10500 jiffies! g88969 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:27544 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1821/0x5740 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7283
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
kthread+0x389/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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: 15765 Comm: syz.9.2823 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xfcf/0x13d0 kernel/smp.c:892
Code: 79 45 8b 2e 44 89 ee 83 e6 01 31 ff e8 7a 06 0c 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 25 02 0c 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 06 01 00 00 00 74 1e e8 0a 02 0c
RSP: 0018:ffffc9001ace7ae0 EFLAGS: 00000246
RAX: ffffffff81b9c256 RBX: ffff8880b863c148 RCX: 0000000000080000
RDX: ffffc90013834000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9001ace7c10 R08: ffffffff9030bcf7 R09: 1ffffffff206179e
R10: dffffc0000000000 R11: ffffffff81746300 R12: 1ffff110170e8169
R13: dffffc0000000000 R14: ffff8880b8740b48 R15: 0000000000000001
FS: 00007f618b0f86c0(0000) GS:ffff88812528a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33023ffc CR3: 0000000074b67000 CR4: 0000000000350ef0
Call Trace:
clock_was_set+0x70a/0x7d0 kernel/time/hrtimer.c:999
do_settimeofday64+0x340/0x570 kernel/time/timekeeping.c:1603
__do_sys_clock_settime kernel/time/posix-timers.c:1124 [inline]
__se_sys_clock_settime kernel/time/posix-timers.c:1108 [inline]
__x64_sys_clock_settime+0x253/0x2a0 kernel/time/posix-timers.c:1108
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f618a19ce59
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:00007f618b0f8028 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3
RAX: ffffffffffffffda RBX: 00007f618a415fa0 RCX: 00007f618a19ce59
RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000000
RBP: 00007f618a232d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f618a416038 R14: 00007f618a415fa0 R15: 00007ffe12f93a98