rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7416/2:b..l
rcu: (detected by 1, t=10502 jiffies, g=18469, q=1499 ncpus=2)
task:syz.4.374 state:R running task stack:25224 pid:7416 tgid:7416 ppid:5820 task_flags:0x2040004c flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7256
irqentry_exit+0x36/0x90 kernel/entry/common.c:211
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:kasan_byte_accessible+0x18/0x30 mm/kasan/generic.c:212
Code: 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 48 b8 00 00 00 00 00 fc ff df 48 c1 ef 03 48 01 c7 0f b6 07 <3c> 07 0f 96 c0 c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 0f
RSP: 0018:ffffc9001c1ee818 EFLAGS: 00000282
RAX: 0000000000000000 RBX: ffffffff8e3c4460 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff816c15f1 RDI: fffffbfff1c7888c
RBP: ffffffff8e3c4460 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 000000000003811d R12: ffffffff816c15f1
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
__kasan_check_byte+0x13/0x50 mm/kasan/common.c:579
kasan_check_byte include/linux/kasan.h:401 [inline]
lock_acquire kernel/locking/lockdep.c:5842 [inline]
lock_acquire+0xfc/0x350 kernel/locking/lockdep.c:5825
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
class_rcu_constructor include/linux/rcupdate.h:1195 [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:56
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
unpoison_slab_object mm/kasan/common.c:342 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:368
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4970 [inline]
slab_alloc_node mm/slub.c:5280 [inline]
kmem_cache_alloc_noprof+0x250/0x6e0 mm/slub.c:5287
kmem_alloc_batch+0x49/0x170 lib/debugobjects.c:371
fill_pool lib/debugobjects.c:403 [inline]
debug_objects_fill_pool lib/debugobjects.c:725 [inline]
debug_objects_fill_pool+0x23f/0x520 lib/debugobjects.c:697
debug_object_activate+0x10b/0x4c0 lib/debugobjects.c:814
debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline]
__call_rcu_common.constprop.0+0x35/0xa10 kernel/rcu/tree.c:3108
slab_free_hook mm/slub.c:2503 [inline]
slab_free mm/slub.c:6630 [inline]
kmem_cache_free+0x171/0x6c0 mm/slub.c:6740
mempool_free+0x102/0x750 mm/mempool.c:576
bio_put_percpu_cache block/bio.c:805 [inline]
bio_put+0x355/0x5b0 block/bio.c:824
bio_endio+0x713/0x860 block/bio.c:1672
blk_update_request+0x93e/0x15f0 block/blk-mq.c:998
blk_mq_end_request+0x4f/0x90 block/blk-mq.c:1160
blk_mq_complete_request block/blk-mq.c:1338 [inline]
blk_mq_complete_request+0x8b/0xb0 block/blk-mq.c:1335
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:2837 [inline]
__blk_mq_flush_list+0x9a/0xc0 block/blk-mq.c:2833
blk_mq_dispatch_queue_requests+0x184/0x7b0 block/blk-mq.c:2882
blk_mq_flush_plug_list+0x1f2/0x600 block/blk-mq.c:2970
blk_add_rq_to_plug+0x1ca/0x540 block/blk-mq.c:1399
blk_mq_submit_bio+0x1ecc/0x3380 block/blk-mq.c:3222
__submit_bio+0x3cf/0x690 block/blk-core.c:637
__submit_bio_noacct_mq block/blk-core.c:724 [inline]
submit_bio_noacct_nocheck+0x53d/0xc10 block/blk-core.c:755
submit_bio_noacct+0xbbb/0x1f60 block/blk-core.c:879
__block_write_full_folio+0x735/0xe00 fs/buffer.c:1933
block_write_full_folio+0x341/0x400 fs/buffer.c:2753
blkdev_writepages+0xb8/0x140 block/fops.c:491
do_writepages+0x27a/0x600 mm/page-writeback.c:2604
filemap_fdatawrite_wbc mm/filemap.c:389 [inline]
filemap_fdatawrite_wbc+0x104/0x160 mm/filemap.c:379
__filemap_fdatawrite_range+0xb9/0x100 mm/filemap.c:422
filemap_write_and_wait_range mm/filemap.c:694 [inline]
filemap_write_and_wait_range+0xa3/0x130 mm/filemap.c:685
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:709
__fput+0x402/0xb70 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:966
do_group_exit+0xd3/0x2a0 kernel/exit.c:1107
__do_sys_exit_group kernel/exit.c:1118 [inline]
__se_sys_exit_group kernel/exit.c:1116 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1116
x64_sys_call+0x150b/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f498d78efc9
RSP: 002b:00007ffd1cf6dba8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f498d78efc9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffd1cf6dc0c R08: 0000001e1cf6dc9f R09: 00000000000927c0
R10: 000000000002e94c R11: 0000000000000246 R12: 0000000000000046
R13: 00000000000927c0 R14: 000000000002e41e R15: 00007ffd1cf6dc60
rcu: rcu_preempt kthread starved for 10101 jiffies! g18469 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:28552 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: 07 6d 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 43 d5 29 00 fb f4 3c 0a 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e007df8 EFLAGS: 000002c6
RAX: 00000000008fd719 RBX: 0000000000000000 RCX: ffffffff8b6052a9
RDX: 0000000000000000 RSI: ffffffff8da2a259 RDI: ffffffff8bf06e40
RBP: fffffbfff1c12f40 R08: 0000000000000001 R09: ffffed1017086655
R10: ffff8880b84332ab R11: 0000000000000001 R12: 0000000000000000
R13: ffffffff8e097a00 R14: ffffffff9081f6d0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888124a0a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555674465c8 CR3: 0000000074d2c000 CR4: 00000000003526f0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x38d/0x500 kernel/sched/idle.c:330
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428
rest_init+0x16b/0x2b0 init/main.c:757
start_kernel+0x3f6/0x4e0 init/main.c:1111
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x148