rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5193/1:b..l P6833/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=18597, q=348 ncpus=2)
task:syz-executor state:R running task stack:21344 pid:6833 tgid:6833 ppid:6817 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7190
irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:114 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:128 [inline]
RIP: 0010:lock_acquire+0xc1/0x340 kernel/locking/lockdep.c:5864
Code: 10 85 c0 0f 85 c0 00 00 00 65 48 8b 04 25 08 10 80 92 83 b8 2c 0b 00 00 00 0f 85 aa 00 00 00 4c 89 74 24 10 4d 89 fe 9c 41 5f 48 c7 c7 61 72 7a 8d e8 f2 ed bb 09 65 ff 05 db 66 e2 10 45 31
RSP: 0018:ffffc900053a6eb8 EFLAGS: 00000246
RAX: ffff88802902bd00 RBX: 0000000000000000 RCX: 0000000080000001
RDX: 0000000000000000 RSI: ffffffff8173fd82 RDI: 1ffffffff1be8354
RBP: ffffffff8173fd65 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff81acf420 R12: 0000000000000002
R13: ffffffff8df41aa0 R14: 0000000000000000 R15: 0000000000000246
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+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495
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_lru_noprof+0x36c/0x6e0 mm/slub.c:5282
__d_alloc+0x37/0x6f0 fs/dcache.c:1730
d_alloc+0x4b/0x190 fs/dcache.c:1809
lookup_one_qstr_excl+0xdc/0x360 fs/namei.c:1751
__start_dirop fs/namei.c:2875 [inline]
start_dirop+0x5c/0x90 fs/namei.c:2884
simple_start_creating+0xc4/0x100 fs/libfs.c:2330
debugfs_start_creating+0xdb/0x1a0 fs/debugfs/inode.c:394
debugfs_create_dir+0x24/0x350 fs/debugfs/inode.c:572
nsim_dev_hwstats_init+0x11d/0x3e0 drivers/net/netdevsim/hwstats.c:418
nsim_drv_probe+0x85d/0xbc0 drivers/net/netdevsim/dev.c:1705
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x26d/0xad0 drivers/base/dd.c:659
__driver_probe_device+0x18c/0x320 drivers/base/dd.c:801
driver_probe_device+0x4f/0x240 drivers/base/dd.c:831
__device_attach_driver+0x279/0x430 drivers/base/dd.c:959
bus_for_each_drv+0x251/0x2e0 drivers/base/bus.c:500
__device_attach+0x2b8/0x430 drivers/base/dd.c:1031
device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1086
bus_probe_device+0x12a/0x220 drivers/base/bus.c:574
device_add+0x7b6/0xb80 drivers/base/core.c:3689
nsim_bus_dev_new drivers/net/netdevsim/bus.c:471 [inline]
new_device_store+0x36c/0x6f0 drivers/net/netdevsim/bus.c:191
kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_write+0x145/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9f8a98e1ff
RSP: 002b:00007ffee98745c0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f9f8a98e1ff
RDX: 0000000000000003 RSI: 00007ffee9874610 RDI: 0000000000000005
RBP: 00007f9f8aa152ef R08: 0000000000000000 R09: 00007ffee9874417
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 00007ffee9874610 R14: 00007f9f8b714620 R15: 0000000000000003
task:udevd state:R running task stack:24568 pid:5193 tgid:5193 ppid:1 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7190
irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_next_frame+0x484/0x23d0 arch/x86/kernel/unwind_orc.c:520
Code: d2 84 c0 48 0f 45 d1 48 89 15 b8 50 12 11 48 85 d2 0f 84 40 02 00 00 4c 8d 62 04 4c 8d 6a 05 4c 89 e0 48 c1 e8 03 0f b6 04 28 <84> c0 0f 85 6d 18 00 00 4c 89 e8 48 c1 e8 03 0f b6 04 28 84 c0 0f
RSP: 0018:ffffc90003c0f8d8 EFLAGS: 00000216
RAX: 0000000000000000 RBX: ffffffff8fa42698 RCX: ffffffff8fa426a0
RDX: ffffffff90253076 RSI: ffffffff90253034 RDI: ffffffff8bc08380
RBP: dffffc0000000000 R08: 0000000000000016 R09: ffffffff8df41aa0
R10: dffffc0000000000 R11: ffffffff81acf420 R12: ffffffff9025307a
R13: ffffffff9025307b R14: ffffc90003c0f9a8 R15: ffffffff8fa4269c
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
getname_flags+0xb8/0x540 fs/namei.c:146
do_readlinkat+0xbc/0x500 fs/stat.c:575
__do_sys_readlink fs/stat.c:613 [inline]
__se_sys_readlink fs/stat.c:610 [inline]
__x64_sys_readlink+0x7f/0x90 fs/stat.c:610
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc0ea5153a7
RSP: 002b:00007ffdfc379988 EFLAGS: 00000206 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007ffdfc379b90 RCX: 00007fc0ea5153a7
RDX: 0000000000000200 RSI: 00007ffdfc379990 RDI: 00007ffdfc379b90
RBP: 000055c9f0c07910 R08: 0000000000000064 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffdfc379990
R13: 000055c9e7f69100 R14: 0000000000000001 R15: 00007ffdfc37a1b0
rcu: rcu_preempt kthread starved for 10613 jiffies! g18597 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:27736 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 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+0x510/0xa50 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:
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: 1e 84 b6 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 91 0e 00 f3 0f 1e fa fb f4 f3 83 b6 f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197e20 EFLAGS: 000002c6
RAX: 0000000000349043 RBX: ffffffff819713ee RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8d7928e5 RDI: ffffffff8bc083e0
RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db
R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8f822470
R13: 1ffff110038d6b70 R14: 0000000000000001 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30affff8 CR3: 0000000079b17000 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+0x1be/0x4d0 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