syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4417/1:b..l
	(detected by 0, t=10502 jiffies, g=9117, q=169)
task:syz.2.46        state:R  running task     stack:26016 pid: 4417 ppid:  4174 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6780
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:jhash2 include/linux/jhash.h:131 [inline]
RIP: 0010:hash_stack lib/stackdepot.c:180 [inline]
RIP: 0010:stack_depot_save+0xc1/0x440 lib/stackdepot.c:272
Code: 89 f6 c1 c6 10 44 31 d6 45 01 de 89 f1 c1 c1 13 41 29 f3 44 31 d9 44 01 f6 41 29 ce 89 cd c1 c5 04 44 31 f5 01 f1 41 83 c1 fd <49> 83 c0 0c 41 83 f9 03 77 8f 45 89 c9 42 ff 24 cd 20 33 5c 8a 49
RSP: 0018:ffffc9000329f500 EFLAGS: 00000213
RAX: 0000000000000000 RBX: 000000000000000d RCX: 00000000eeb329d5
RDX: 0000000000000a20 RSI: 00000000f8f9073a RDI: ffffc9000329f560
RBP: 00000000281a71e2 R08: ffffc9000329f590 R09: 000000000000000b
R10: 000000001f81ce7f R11: 0000000097ae5eaf R12: ffff88805f0a9ea8
R13: ffff888144bf0140 R14: 0000000073b8585d R15: ffffc9000329f560
 kasan_save_stack mm/kasan/common.c:40 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 __kasan_slab_alloc+0xb3/0xd0 mm/kasan/common.c:467
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3220 [inline]
 slab_alloc mm/slub.c:3228 [inline]
 kmem_cache_alloc+0x100/0x290 mm/slub.c:3233
 skb_clone+0x1bd/0x350 net/core/skbuff.c:1523
 ____bpf_clone_redirect net/core/filter.c:2437 [inline]
 bpf_clone_redirect+0xa9/0x390 net/core/filter.c:2422
 bpf_prog_5af0f20e2961581c+0x56/0x568
 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 bpf_test_run+0x317/0x870 net/bpf/test_run.c:119
 bpf_prog_test_run_skb+0x9cc/0x1180 net/bpf/test_run.c:669
 bpf_prog_test_run+0x31e/0x390 kernel/bpf/syscall.c:3368
 __sys_bpf+0x535/0x670 kernel/bpf/syscall.c:4669
 __do_sys_bpf kernel/bpf/syscall.c:4755 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4753 [inline]
 __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4753
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f2ddf84d929
RSP: 002b:00007f2ddd6b5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f2ddfa74fa0 RCX: 00007f2ddf84d929
RDX: 0000000000000050 RSI: 0000200000002300 RDI: 000000000000000a
RBP: 00007f2ddf8cfb39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f2ddfa74fa0 R15: 00007fff8a467dc8
 </TASK>
rcu: rcu_preempt kthread starved for 10515 jiffies! g9117 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:27848 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1e0 kernel/sched/core.c:6459
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4418 Comm: syz.3.43 Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:check_preemption_disabled+0x60/0x110 lib/smp_processor_id.c:19
Code: 00 48 3b 4c 24 08 0f 85 c4 00 00 00 48 83 c4 10 5b 41 5e 41 5f 5d c3 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 <74> cc 65 4c 8b 3d 86 f2 60 76 41 f6 47 2f 04 74 0a 41 83 bf 10 04
RSP: 0018:ffffc90002f5fd28 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000080000000
RDX: 0000000000000000 RSI: ffffffff8a0b1fc0 RDI: ffffffff8a59a740
RBP: ffffc90002f5fe80 R08: dffffc0000000000 R09: fffffbfff1ad157e
R10: fffffbfff1ad157e R11: 1ffffffff1ad157d R12: ffff888029a90728
R13: 1ffff920005ebfb8 R14: 0000000000000046 R15: dffffc0000000000
FS:  00007fa8023796c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c410a49 CR3: 000000005f9f8000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lockdep_recursion_inc kernel/locking/lockdep.c:431 [inline]
 lock_acquire+0x15f/0x3f0 kernel/locking/lockdep.c:5622
 do_write_seqcount_begin_nested include/linux/seqlock.h:519 [inline]
 do_write_seqcount_begin include/linux/seqlock.h:545 [inline]
 vtime_user_enter+0x96/0x2d0 kernel/sched/cputime.c:715
 __context_tracking_enter+0x60/0x90 kernel/context_tracking.c:82
 user_enter_irqoff include/linux/context_tracking.h:41 [inline]
 __exit_to_user_mode kernel/entry/common.c:136 [inline]
 syscall_exit_to_user_mode+0x3c/0x40 kernel/entry/common.c:309
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fa804412980
Code: 44 24 20 0f 29 44 24 30 0f 29 44 24 40 48 8b 44 24 08 ff d0 48 83 c4 50 31 c0 5b 5d 41 5c 41 5d 41 5e c3 0f 1f 80 00 00 00 00 <c3> 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 c3 66 66 2e 0f 1f
RSP: 002b:00007fa802378b38 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007fa80477b168 RCX: 00007fa804553929
RDX: 00007fa802378b40 RSI: 00007fa802378c70 RDI: 0000000000000011
RBP: 00007fa80477b160 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa80477b16c
R13: 0000000000000000 R14: 00007fffcbfa0a30 R15: 00007fffcbfa0b18
 </TASK>
sched: RT throttling activated