syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=6324/1/0x4000000000000000 softirq=80072/80073 fqs=201
rcu: 	(detected by 1, t=10502 jiffies, g=55253, q=314 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 14638 Comm: syz.1.2208 Not tainted 6.17.0-rc2-syzkaller-00028-gbe48bcf004f9 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:kasan_mem_to_shadow include/linux/kasan.h:65 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:130 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:161 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x4d/0x1b0 mm/kasan/generic.c:189
Code: cc cc cc 48 b8 00 00 00 00 00 00 00 ff eb 0a 48 b8 00 00 00 00 00 80 ff ff 48 39 c7 0f 82 b3 00 00 00 4c 8d 54 37 ff 48 89 fd <48> b8 00 00 00 00 00 fc ff df 4d 89 d1 48 c1 ed 03 49 c1 e9 03 48
RSP: 0018:ffffc90000007e20 EFLAGS: 00000006
RAX: ffff800000000000 RBX: ffff8880b8427d80 RCX: ffffffff81a85ec8
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90ab3f90
RBP: ffffffff90ab3f90 R08: 0000000000000000 R09: 0000000000000007
R10: ffffffff90ab3f97 R11: ffffffff9b0655c0 R12: ffff8880b8427c80
R13: 0000000000000000 R14: ffff888021aea340 R15: ffffffff89a795a0
FS:  00007fedbfc386c0(0000) GS:ffff8881246bc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fedbfc16f98 CR3: 0000000058b15000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 cpumask_test_cpu include/linux/cpumask.h:646 [inline]
 cpu_online include/linux/cpumask.h:1205 [inline]
 trace_hrtimer_expire_entry include/trace/events/timer.h:259 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1758 [inline]
 __hrtimer_run_queues+0x578/0xad0 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:write_comp_data+0x0/0x90 kernel/kcov.c:240
Code: 48 8b 05 db b4 1a 12 48 8b 80 30 16 00 00 e9 97 05 db 09 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <49> 89 d2 49 89 f8 49 89 f1 65 48 8b 15 a7 b4 1a 12 65 8b 05 b8 b4
RSP: 0018:ffffc9000c6e7958 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff82458b58
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: ffffc9000c6e79e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000001000 R11: 000000000001349c R12: 1ffff920018dcf3e
R13: ffff888073085318 R14: dffffc0000000000 R15: 1ffff920018dcf59
 rcu_read_lock include/linux/rcupdate.h:842 [inline]
 __dentry_path+0x58/0x7e0 fs/d_path.c:337
 dentry_path_raw+0xcd/0x120 fs/d_path.c:367
 selinux_genfs_get_sid security/selinux/hooks.c:1332 [inline]
 inode_doinit_with_dentry+0x908/0x12e0 security/selinux/hooks.c:1551
 selinux_d_instantiate+0x26/0x30 security/selinux/hooks.c:6519
 security_d_instantiate+0x142/0x1a0 security/security.c:4109
 d_instantiate+0x5c/0x90 fs/dcache.c:1961
 debugfs_create_dir+0x1b5/0x5f0 fs/debugfs/inode.c:595
 bdi_debug_register mm/backing-dev.c:235 [inline]
 bdi_register_va+0x2c0/0x820 mm/backing-dev.c:1101
 super_setup_bdi_name+0xff/0x250 fs/super.c:1874
 ceph_setup_bdi fs/ceph/super.c:1288 [inline]
 ceph_get_tree+0x9bc/0x1ec0 fs/ceph/super.c:1350
 vfs_get_tree+0x8e/0x340 fs/super.c:1815
 vfs_cmd_create+0xd7/0x2a0 fs/fsopen.c:225
 vfs_fsconfig_locked fs/fsopen.c:289 [inline]
 __do_sys_fsconfig+0x7b8/0xbe0 fs/fsopen.c:467
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fedbed8ebe9
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:00007fedbfc38038 EFLAGS: 00000246 ORIG_RAX: 00000000000001af
RAX: ffffffffffffffda RBX: 00007fedbefb5fa0 RCX: 00007fedbed8ebe9
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003
RBP: 00007fedbee11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fedbefb6038 R14: 00007fedbefb5fa0 R15: 00007fff92559b88
 </TASK>
rcu: rcu_preempt kthread starved for 10092 jiffies! g55253 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:27912 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.17.0-rc2-syzkaller-00028-gbe48bcf004f9 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: 5c 62 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 d3 72 16 00 fb f4 <e9> 4c 09 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197df8 EFLAGS: 000002c2
RAX: 000000000231aa7c RBX: 0000000000000001 RCX: ffffffff8b939c29
RDX: ffffed10170a6656 RSI: ffffffff8c162880 RDI: ffffffff819133c1
RBP: ffffed1003c56488 R08: 0000000000000000 R09: ffffed10170a6655
R10: ffff8880b85332ab R11: 0000000000000001 R12: 0000000000000001
R13: ffff88801e2b2440 R14: ffffffff90ab3f90 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881247bc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000c2c0 CR3: 000000003112c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:757
 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:190 [inline]
 do_idle+0x391/0x510 kernel/sched/idle.c:330
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428
 start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315
 common_startup_64+0x13e/0x148
 </TASK>