syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P23968/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=215985, q=312 ncpus=2)
task:syz-executor    state:R  running task     stack:20808 pid:23968 ppid:23961  flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x1553/0x45a0 kernel/sched/core.c:6700
 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__get_obj_cgroup_from_memcg+0x51/0xe0 mm/memcontrol.c:3042
Code: 55 a3 a4 0c 0f 84 95 00 00 00 4c 8d b3 f0 08 00 00 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 42 d4 f8 ff 4d 8b 36 <e8> 2a a3 9e 08 85 c0 74 09 e8 31 42 89 ff 85 c0 74 30 4d 85 f6 74
RSP: 0018:ffffc900031f7c48 EFLAGS: 00000246
RAX: 1ffff1100d21f91e RBX: ffff8880690fc000 RCX: 04351314f39ea500
RDX: 0000000000000000 RSI: ffffffff8acadae0 RDI: ffff8880690fc000
RBP: 0000000000000cc0 R08: dffffc0000000000 R09: 1ffffffff22382a0
R10: dffffc0000000000 R11: fffffbfff22382a1 R12: ffff888142a427a8
R13: ffffc900031f7de0 R14: ffff88801b3e0c00 R15: dffffc0000000000
 get_obj_cgroup_from_current+0x16f/0x280 mm/memcontrol.c:3063
 memcg_slab_pre_alloc_hook mm/slab.h:492 [inline]
 slab_pre_alloc_hook+0x91/0x310 mm/slab.h:719
 slab_alloc_node mm/slub.c:3477 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc_lru+0x4d/0x2d0 mm/slub.c:3526
 __d_alloc+0x31/0x730 fs/dcache.c:1773
 d_alloc_pseudo+0x1d/0x70 fs/dcache.c:1905
 alloc_file_pseudo+0xe4/0x210 fs/file_table.c:329
 sock_alloc_file+0xb7/0x280 net/socket.c:469
 sock_map_fd net/socket.c:494 [inline]
 __sys_socket+0x13d/0x1a0 net/socket.c:1723
 __do_sys_socket net/socket.c:1728 [inline]
 __se_sys_socket net/socket.c:1726 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1726
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f821af9e007
RSP: 002b:00007fff8aff2748 EFLAGS: 00000206 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f821af9e007
RDX: 0000000000000006 RSI: 0000000000000001 RDI: 0000000000000002
RBP: 00007fff8aff2e4c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 00000000000000ff
R13: 00000000000927c0 R14: 000000000016de21 R15: 00007fff8aff2ea0
 </TASK>
rcu: rcu_preempt kthread starved for 10403 jiffies! g215985 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:26888 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x1553/0x45a0 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148
Code: 40 22 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d c3 29 43 00 fb f4 <c3> 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80
RSP: 0018:ffffffff8ce07d80 EFLAGS: 000002c6
RAX: 97e5f51687e5c400 RBX: ffffffff8162ac40 RCX: 97e5f51687e5c400
RDX: 0000000000000001 RSI: ffffffff8acac960 RDI: ffffffff8b1c85a0
RBP: ffffffff8ce07eb8 R08: ffff8880b8e36b2b R09: 1ffff110171c6d65
R10: dffffc0000000000 R11: ffffed10171c6d66 R12: 1ffffffff19d2688
R13: 1ffffffff19c0fbc R14: 0000000000000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb510bdc7d3 CR3: 000000007b0d0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 000000000000000e DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:753
 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
 cpuidle_idle_call kernel/sched/idle.c:170 [inline]
 do_idle+0x1f0/0x4e0 kernel/sched/idle.c:282
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
 rest_init+0x2e2/0x300 init/main.c:744
 arch_call_rest_init+0xe/0x10 init/main.c:841
 start_kernel+0x459/0x4e0 init/main.c:1086
 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555
 x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536
 secondary_startup_64_no_verify+0x179/0x17b
 </TASK>