rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6297/1:b..l P3571/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=20565, q=251 ncpus=2)
task:kworker/u8:10 state:R running task stack:22120 pid:3571 tgid:3571 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: kvfree_rcu_reclaim kfree_rcu_work
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6863
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190
irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__read_once_word_nocheck+0x0/0x10 include/asm-generic/rwonce.h:67
Code: e8 c5 ab b3 00 48 ba 00 00 00 00 00 fc ff df e9 88 fc ff ff 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <48> 8b 07 c3 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90
RSP: 0018:ffffc9000c217318 EFLAGS: 00000202
RAX: ffffc9000c217d01 RBX: ffffc9000c210000 RCX: 0000000000000001
RDX: ffffc9000c217488 RSI: dffffc0000000000 RDI: ffffc9000c217d50
RBP: 1ffff92001842e89 R08: ffffc9000c217d50 R09: 0000000000000000
R10: ffffc9000c217498 R11: fffff52001842e95 R12: 1ffff92001842e8a
R13: 1ffff92001842e8b R14: ffffc9000c218000 R15: dffffc0000000000
deref_stack_reg+0x19f/0x230 arch/x86/kernel/unwind_orc.c:422
unwind_next_frame+0x18cc/0x23d0 arch/x86/kernel/unwind_orc.c:-1
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2540 [inline]
slab_free_freelist_hook mm/slub.c:2569 [inline]
slab_free_bulk mm/slub.c:6703 [inline]
kmem_cache_free_bulk+0x3fb/0xdb0 mm/slub.c:7390
kfree_bulk include/linux/slab.h:830 [inline]
kvfree_rcu_bulk+0xe5/0x1f0 mm/slab_common.c:1523
kfree_rcu_work+0xed/0x170 mm/slab_common.c:1601
process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
process_scheduled_works kernel/workqueue.c:3362 [inline]
worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
task:kworker/u8:19 state:R running task stack:23216 pid:6297 tgid:6297 ppid:2 task_flags:0x24248060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6863
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190
irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_next_frame+0xc98/0x23d0 arch/x86/kernel/unwind_orc.c:596
Code: b6 04 28 84 c0 0f 85 b7 15 00 00 48 0f bf 02 49 01 c4 48 8d 5e 01 48 8b 44 24 40 0f b6 04 28 84 c0 0f 85 6f 11 00 00 49 89 df <49> c1 ef 03 41 0f b6 04 2f 84 c0 0f 85 7f 11 00 00 0f b6 76 01 83
RSP: 0018:ffffc9000b886238 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff90296753 RCX: ffffffff8fa7507c
RDX: ffffffff9029674e RSI: ffffffff90296752 RDI: ffffffff8bc08300
RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffffff8df41a60
R10: ffffc9000b886358 R11: ffffffff81ada980 R12: ffffc9000b886c60
R13: ffffc9000b886358 R14: ffffc9000b886308 R15: ffffffff90296753
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4953 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5270
mempool_alloc_noprof+0x1c9/0x2f0 mm/mempool.c:567
bio_alloc_bioset+0x28d/0x12d0 block/bio.c:561
bio_alloc include/linux/bio.h:374 [inline]
io_submit_init_bio fs/ext4/page-io.c:426 [inline]
io_submit_add_bh fs/ext4/page-io.c:448 [inline]
ext4_bio_write_folio+0x10d9/0x1f20 fs/ext4/page-io.c:589
mpage_process_page_bufs+0x6d5/0x8e0 fs/ext4/inode.c:2198
mpage_prepare_extent_to_map+0xdcc/0x1660 fs/ext4/inode.c:2737
ext4_do_writepages+0xb74/0x4500 fs/ext4/inode.c:2878
ext4_writepages+0x203/0x350 fs/ext4/inode.c:3026
do_writepages+0x32e/0x550 mm/page-writeback.c:2598
__writeback_single_inode+0x133/0x1240 fs/fs-writeback.c:1737
writeback_sb_inodes+0x93a/0x1870 fs/fs-writeback.c:2030
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2107
wb_writeback+0x43f/0xaa0 fs/fs-writeback.c:2218
wb_check_old_data_flush fs/fs-writeback.c:2322 [inline]
wb_do_writeback fs/fs-writeback.c:2375 [inline]
wb_workfn+0xad2/0xed0 fs/fs-writeback.c:2403
process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
process_scheduled_works kernel/workqueue.c:3362 [inline]
worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
rcu: rcu_preempt kthread starved for 10596 jiffies! g20565 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:27128 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
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 10/25/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: cc cc cc cc cc cc cc 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 13 50 0c 00 f3 0f 1e fa fb f4 c8 ed 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8dc07d80 EFLAGS: 000002c6
RAX: a5668ea9f9da5800 RBX: ffffffff8197983a RCX: a5668ea9f9da5800
RDX: 0000000000000001 RSI: ffffffff8d7939c1 RDI: ffffffff8bc08360
RBP: ffffffff8dc07ea8 R08: ffff8880b86336db R09: 1ffff110170c66db
R10: dffffc0000000000 R11: ffffed10170c66dc R12: ffffffff8f822a70
R13: 1ffffffff1b92a68 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125e31000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c32eaa7 CR3: 0000000032e08000 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+0x73/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x1ea/0x520 kernel/sched/idle.c:332
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
rest_init+0x2de/0x300 init/main.c:757
start_kernel+0x3a7/0x400 init/main.c:1206
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x147