rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6283/1:b..l P5837/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=16033, q=746 ncpus=2)
task:syz-executor state:R running task stack:19496 pid:5837 tgid:5837 ppid:5821 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5257 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6864
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7191
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:__orc_find arch/x86/kernel/unwind_orc.c:109 [inline]
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline]
RIP: 0010:unwind_next_frame+0x2b4/0x2390 arch/x86/kernel/unwind_orc.c:494
Code: 00 00 fc ff df 0f 84 03 02 00 00 4a 8d 14 ad 44 e8 92 8f 45 29 e8 4a 8d 1c 82 48 83 c3 fc 49 89 d5 48 39 da 0f 86 1c 10 00 00 <49> 29 d5 e9 80 00 00 00 31 db e9 eb 16 00 00 49 81 fc 00 10 e9 90
RSP: 0018:ffffc90003faf438 EFLAGS: 00000212
RAX: ffffffff8fb93af8 RBX: ffffffff8fb93afc RCX: ffffffff8fb93b00
RDX: ffffffff8fb93afc RSI: ffffffff9044a8f0 RDI: ffffffff8bc01880
RBP: ffffffff8fb93b00 R08: 0000000000000001 R09: ffffffff8df419e0
R10: ffffc90003faf558 R11: ffffffff81ada230 R12: ffffffff84437c92
R13: ffffffff8fb93afc R14: ffffc90003faf508 R15: ffffffff8fb93afc
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
poison_kmalloc_redzone mm/kasan/common.c:397 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414
kasan_kmalloc include/linux/kasan.h:262 [inline]
__do_kmalloc_node mm/slub.c:5652 [inline]
__kmalloc_noprof+0x41d/0x800 mm/slub.c:5664
kmalloc_noprof include/linux/slab.h:961 [inline]
tomoyo_realpath_from_path+0xe3/0x5d0 security/tomoyo/realpath.c:251
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_path_perm+0x213/0x4b0 security/tomoyo/file.c:822
security_inode_getattr+0x12f/0x330 security/security.c:1869
vfs_getattr fs/stat.c:259 [inline]
vfs_statx_path fs/stat.c:299 [inline]
vfs_statx+0x18e/0x550 fs/stat.c:356
vfs_fstatat+0x118/0x170 fs/stat.c:375
__do_sys_newfstatat fs/stat.c:542 [inline]
__se_sys_newfstatat fs/stat.c:536 [inline]
__x64_sys_newfstatat+0x116/0x190 fs/stat.c:536
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: 0033:0x7f7f8ef8de3a
RSP: 002b:00007ffd597fc438 EFLAGS: 00000286 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 00007f7f8f013d7d RCX: 00007f7f8ef8de3a
RDX: 00007ffd597fc460 RSI: 00007ffd597fc4f0 RDI: 00000000ffffff9c
RBP: 00007ffd597fc4f0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000286 R12: 00007ffd597fd580
R13: 00007f7f8f013d7d R14: 0000000000024af3 R15: 00007ffd597fd5c0
task:syz.1.80 state:R running task stack:25336 pid:6283 tgid:6282 ppid:5836 task_flags:0x400040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5257 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6864
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7191
irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_is_held include/linux/lockdep.h:249 [inline]
RIP: 0010:rcu_read_lock_held+0x22/0x50 kernel/rcu/update.c:351
Code: 90 90 90 90 90 90 90 90 f3 0f 1e fa 53 e8 16 fe b2 09 85 c0 74 26 31 db e8 7b 32 01 00 84 c0 74 20 e8 a2 7a 01 00 84 c0 74 17 <48> c7 c7 e0 19 f4 8d be ff ff ff ff 5b e9 2c fa b2 09 bb 01 00 00
RSP: 0018:ffffc9000b8176b8 EFLAGS: 00000202
RAX: 1ffffffff1be8d01 RBX: 0000000000000000 RCX: 062efac9583bba00
RDX: ffff88802f6f1e80 RSI: ffffffff8bc018c0 RDI: ffff8880b873b8e8
RBP: 0000000000000000 R08: ffffffff8476b64d R09: ffffffff8df419e0
R10: dffffc0000000000 R11: fffff940003572ff R12: ffffc9000b8177c0
R13: 000000000000053d R14: ffff88802f6f1eac R15: dffffc0000000000
task_css include/linux/cgroup.h:460 [inline]
blkcg_css+0x113/0x1d0 block/blk-cgroup.c:110
blk_cgroup_congested+0xbc/0x210 block/blk-cgroup.c:2238
__folio_throttle_swaprate+0x3c/0x140 mm/swapfile.c:4034
folio_throttle_swaprate include/linux/swap.h:608 [inline]
shmem_add_to_page_cache+0x6f1/0xba0 mm/shmem.c:899
shmem_alloc_and_add_folio+0x829/0xf40 mm/shmem.c:1958
shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2556
shmem_get_folio mm/shmem.c:2662 [inline]
shmem_write_begin+0x16c/0x330 mm/shmem.c:3315
generic_perform_write+0x2c5/0x900 mm/filemap.c:4314
shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3490
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+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f13b898e1ff
RSP: 002b:00007f13b97c2df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000013bd7ef RCX: 00007f13b898e1ff
RDX: 00000000013bd7ef RSI: 00007f13ae600000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000000558d
R10: 00002000000061c2 R11: 0000000000000293 R12: 0000000000000003
R13: 00007f13b97c2ef0 R14: 00007f13b97c2eb0 R15: 00007f13ae600000
rcu: rcu_preempt kthread starved for 10582 jiffies! g16033 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:27736 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5257 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6864
__schedule_loop kernel/sched/core.c:6946 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6961
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:
CPU: 0 UID: 0 PID: 6300 Comm: syz.3.87 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:asm_fred_entry_from_kvm+0x58/0x60 arch/x86/entry/entry_64_fred.S:146
Code: 41 54 41 55 41 56 41 57 31 f6 31 d2 31 c9 45 31 c0 45 31 c9 45 31 d2 45 31 db 48 89 e7 e8 50 05 00 00 66 90 48 89 ec 0f 1f 00 <5d> e9 12 5b 03 00 cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000b5572d0 EFLAGS: 00000082 ORIG_RAX: 0000000000000000
RAX: ffffffff8b58f1c8 RBX: ffff88806d640000 RCX: 0000000000080000
RDX: ffff88806d640c32 RSI: 000000000007ffff RDI: 020000ec00000018
RBP: ffffc9000b5572d0 R08: ffff8880267bdb80 R09: 0000000000000003
R10: 0000000000000029 R11: 0000000000000002 R12: dffffc0000000000
R13: 1ffff920016aae60 R14: 000000ec00000000 R15: 1ffff1100dac8186
FS: 00007f94e75d26c0(0000) GS:ffff888125e4f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007f4f4000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
fred_entry_from_kvm arch/x86/include/asm/fred.h:85 [inline]
handle_external_interrupt_irqoff arch/x86/kvm/vmx/vmx.c:7091 [inline]
vmx_handle_exit_irqoff+0x40a/0x960 arch/x86/kvm/vmx/vmx.c:7106
vcpu_enter_guest arch/x86/kvm/x86.c:11409 [inline]
vcpu_run+0x51b4/0x76b0 arch/x86/kvm/x86.c:11632
kvm_arch_vcpu_ioctl_run+0x1148/0x1c90 arch/x86/kvm/x86.c:11977
kvm_vcpu_ioctl+0x99a/0xed0 virt/kvm/kvm_main.c:4468
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
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: 0033:0x7f94e678f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f94e75d2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f94e69e5fa0 RCX: 00007f94e678f749
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 000000000000000b
RBP: 00007f94e6813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f94e69e6038 R14: 00007f94e69e5fa0 R15: 00007ffd5647aa58