rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13044/2:b..l
rcu: (detected by 0, t=10502 jiffies, g=47965, q=1277 ncpus=2)
task:syz.4.1266 state:R running task stack:25512 pid:13044 tgid:13039 ppid:5856 task_flags:0x2040044c flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6961
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288
irqentry_exit+0x36/0x90 kernel/entry/common.c:197
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5872
Code: d6 3e 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 22 98 13 0f 0f 82 74 02 00 00 8b 35 da c9 13 0f 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 79 d6 3e 12 0f 85 c7 02 00 00 48 83 c4
RSP: 0018:ffffc9000c876c90 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e5c1260 RCX: 00000000c639c71c
RDX: 0000000000000000 RSI: ffffffff8de2bfa8 RDI: ffffffff8c162b00
RBP: 0000000000000002 R08: f501fefe41178ce3 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:841 [inline]
class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:388 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405
kmalloc_noprof include/linux/slab.h:905 [inline]
slab_free_hook mm/slub.c:2374 [inline]
slab_free mm/slub.c:4695 [inline]
kmem_cache_free+0x142/0x4d0 mm/slub.c:4797
mempool_free+0xff/0x750 mm/mempool.c:576
bio_put_percpu_cache block/bio.c:801 [inline]
bio_put+0x355/0x5b0 block/bio.c:820
bio_endio+0x710/0x860 block/bio.c:1651
blk_update_request+0x93e/0x15f0 block/blk-mq.c:989
blk_mq_end_request+0x4f/0x90 block/blk-mq.c:1151
blk_mq_complete_request block/blk-mq.c:1329 [inline]
blk_mq_complete_request+0x8b/0xb0 block/blk-mq.c:1326
nullb_complete_cmd drivers/block/null_blk/main.c:1402 [inline]
null_handle_cmd drivers/block/null_blk/main.c:1454 [inline]
null_queue_rq+0xb69/0xfd0 drivers/block/null_blk/main.c:1693
null_queue_rqs+0xe9/0x2f0 drivers/block/null_blk/main.c:1707
__blk_mq_flush_list block/blk-mq.c:2828 [inline]
__blk_mq_flush_list+0x97/0xc0 block/blk-mq.c:2824
blk_mq_dispatch_queue_requests+0x184/0x7b0 block/blk-mq.c:2873
blk_mq_flush_plug_list+0x1f2/0x600 block/blk-mq.c:2961
__blk_flush_plug+0x2c4/0x4b0 block/blk-core.c:1220
blk_finish_plug block/blk-core.c:1247 [inline]
blk_finish_plug+0x53/0xa0 block/blk-core.c:1244
blkdev_writepages+0xe9/0x140 block/fops.c:484
do_writepages+0x27a/0x600 mm/page-writeback.c:2634
filemap_fdatawrite_wbc mm/filemap.c:386 [inline]
filemap_fdatawrite_wbc+0x104/0x160 mm/filemap.c:376
__filemap_fdatawrite_range+0xb9/0x100 mm/filemap.c:419
filemap_write_and_wait_range mm/filemap.c:691 [inline]
filemap_write_and_wait_range+0xa3/0x130 mm/filemap.c:682
filemap_write_and_wait include/linux/pagemap.h:68 [inline]
sync_blockdev block/bdev.c:260 [inline]
sync_blockdev block/bdev.c:256 [inline]
bdev_release+0x4d3/0x6d0 block/bdev.c:1126
blkdev_release+0x15/0x20 block/fops.c:699
__fput+0x3ff/0xb70 fs/file_table.c:468
task_work_run+0x150/0x240 kernel/task_work.c:227
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x86f/0x2bf0 kernel/exit.c:961
do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
get_signal+0x2673/0x26d0 kernel/signal.c:3034
arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:40
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5c1bd8ebe9
RSP: 002b:00007f5c1cb5a0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f5c1bfc6188 RCX: 00007f5c1bd8ebe9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f5c1bfc6188
RBP: 00007f5c1bfc6180 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5c1bfc6218 R14: 00007ffc5b9bd6f0 R15: 00007ffc5b9bd7d8
rcu: rcu_preempt kthread starved for 9856 jiffies! g47965 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:27784 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
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+0x5d4/0x6f0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: ec 61 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 53 e3 15 00 fb f4 8c 09 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197df8 EFLAGS: 000002c2
RAX: 0000000002caf58f RBX: 0000000000000001 RCX: ffffffff8b942c29
RDX: 0000000000000000 RSI: ffffffff8de514d0 RDI: ffffffff8c162b00
RBP: ffffed1003c5d488 R08: 0000000000000001 R09: ffffed10170a6655
R10: ffff8880b85332ab R11: 0000000000000000 R12: 0000000000000001
R13: ffff88801e2ea440 R14: ffffffff90ab6190 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881247b6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f50d5199339 CR3: 000000002d235000 CR4: 00000000003526f0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:757
default_idle_call+0x6d/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x391/0x510 kernel/sched/idle.c:330
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428
start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315
common_startup_64+0x13e/0x148