rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6477/1:b..l P6490/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=15621, q=1098 ncpus=2)
task:syz.4.119 state:R running task stack:26440 pid:6490 tgid:6487 ppid:5837 task_flags:0x400140 flags:0x00080000
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:lockdep_enabled kernel/locking/lockdep.c:118 [inline]
RIP: 0010:lock_acquire+0x8b/0x340 kernel/locking/lockdep.c:5844
Code: 0f 84 d7 01 00 00 83 3d 82 17 e3 0d 00 0f 84 f0 00 00 00 48 8b b4 24 90 00 00 00 4c 89 ef e8 5c ec 88 00 83 3d 65 17 e3 0d 00 <0f> 84 fa 00 00 00 65 8b 05 38 ca da 10 85 c0 0f 85 eb 00 00 00 65
RSP: 0018:ffffc9001d70f238 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 84927c06e0597c00
RDX: 0000000000000000 RSI: ffffffff8173ef42 RDI: 1ffffffff1be8398
RBP: ffffffff8173ef25 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff81ad4ad0 R12: 0000000000000002
R13: ffffffff8df41cc0 R14: 0000000000000000 R15: 0000000000000000
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+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
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:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
unpoison_slab_object mm/kasan/common.c:342 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4948 [inline]
slab_alloc_node mm/slub.c:5258 [inline]
kmem_cache_alloc_noprof+0x367/0x6f0 mm/slub.c:5265
kmem_alloc_batch lib/debugobjects.c:371 [inline]
fill_pool+0x100/0x570 lib/debugobjects.c:403
debug_objects_fill_pool lib/debugobjects.c:725 [inline]
__debug_object_init+0x3e1/0x4b0 lib/debugobjects.c:737
debug_timer_init kernel/time/timer.c:788 [inline]
debug_init kernel/time/timer.c:836 [inline]
timer_init_key+0x41/0x2b0 kernel/time/timer.c:880
bdi_alloc+0x112/0x140 mm/backing-dev.c:1037
super_setup_bdi_name+0x9b/0x200 fs/super.c:1813
fuse_bdi_init fs/fuse/inode.c:1589 [inline]
fuse_fill_super_common+0x671/0x1210 fs/fuse/inode.c:1865
fuse_fill_super+0x176/0x1f0 fs/fuse/inode.c:1946
vfs_get_super fs/super.c:1332 [inline]
get_tree_nodev+0xbb/0x150 fs/super.c:1351
fuse_get_tree+0x2fb/0x4f0 fs/fuse/inode.c:2023
vfs_get_tree+0x92/0x2a0 fs/super.c:1759
fc_mount fs/namespace.c:1199 [inline]
do_new_mount_fc fs/namespace.c:3636 [inline]
do_new_mount+0x302/0xa10 fs/namespace.c:3712
do_mount fs/namespace.c:4035 [inline]
__do_sys_mount fs/namespace.c:4224 [inline]
__se_sys_mount+0x313/0x410 fs/namespace.c:4201
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7ba2f8f749
RSP: 002b:00007f7ba3e3b038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f7ba31e5fa0 RCX: 00007f7ba2f8f749
RDX: 0000200000002100 RSI: 00002000000020c0 RDI: 0000000000000000
RBP: 00007f7ba3013f91 R08: 00002000000002c0 R09: 0000000000000000
R10: 0000000000000080 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7ba31e6038 R14: 00007f7ba31e5fa0 R15: 00007ffedb26abf8
task:syz.1.115 state:R running task stack:24472 pid:6477 tgid:6476 ppid:5836 task_flags:0x400140 flags:0x00080000
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_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210
Code: 89 fb e8 23 00 00 00 48 8b 3d b4 db d8 0b 48 89 de 5b e9 13 e6 5a 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 b0 78 92 65 8b 15 b8 65
RSP: 0018:ffffc9000e737310 EFLAGS: 00000282
RAX: 1ffffffff3316348 RBX: 0000000000029b7f RCX: 0000000000080000
RDX: ffffc9000bfe9000 RSI: 000000000002132f RDI: 0000000000021330
RBP: dffffc0000000000 R08: ffff88801b8897af R09: 1ffff110037112f5
R10: dffffc0000000000 R11: ffffed10037112f6 R12: 0000000000000000
R13: 0000000000029b7f R14: dffffc0000000000 R15: ffff88801b8897b0
__page_table_check_zero+0x28e/0x3e0 mm/page_table_check.c:139
page_table_check_alloc include/linux/page_table_check.h:35 [inline]
post_alloc_hook+0x247/0x290 mm/page_alloc.c:1846
prep_new_page mm/page_alloc.c:1853 [inline]
get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3879
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
alloc_slab_page mm/slub.c:3075 [inline]
allocate_slab+0x86/0x3b0 mm/slub.c:3248
new_slab mm/slub.c:3302 [inline]
___slab_alloc+0xf2b/0x1960 mm/slub.c:4651
__kmem_cache_alloc_bulk+0x1d9/0x550 mm/slub.c:7417
kmem_cache_alloc_bulk_noprof+0x3aa/0x710 mm/slub.c:7483
__io_alloc_req_refill+0x9d/0x340 io_uring/io_uring.c:1025
io_alloc_req io_uring/io_uring.h:562 [inline]
io_submit_sqes+0xe58/0x2140 io_uring/io_uring.c:2423
__do_sys_io_uring_enter io_uring/io_uring.c:3277 [inline]
__se_sys_io_uring_enter+0x2e0/0x2b60 io_uring/io_uring.c:3216
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8def78f749
RSP: 002b:00007f8df0543038 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 00007f8def9e5fa0 RCX: 00007f8def78f749
RDX: 0000000000000000 RSI: 00000000000047bc RDI: 0000000000000006
RBP: 00007f8def813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8def9e6038 R14: 00007f8def9e5fa0 R15: 00007ffd71825648
rcu: rcu_preempt kthread starved for 10275 jiffies! g15621 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:27136 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 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 10/25/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: be 13 c4 f5 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 53 1d 1c 00 f3 0f 1e fa fb f4 93 13 c4 f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6
RAX: e222007722ff0e00 RBX: ffffffff8197438a RCX: e222007722ff0e00
RDX: 0000000000000001 RSI: ffffffff8d781d94 RDI: ffffffff8bbffbe0
RBP: ffffc90000197f10 R08: ffff8880b893359b R09: 1ffff110171266b3
R10: dffffc0000000000 R11: ffffed10171266b4 R12: ffffffff8f811170
R13: 1ffff110038dfb70 R14: 0000000000000001 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888126195000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005597d662ba38 CR3: 0000000076773000 CR4: 0000000000350ef0
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
start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x147