syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10499 ticks this GP) idle=18a4/1/0x4000000000000000 softirq=110610/110610 fqs=127
	(t=10500 jiffies g=142749 q=8 ncpus=2)
rcu: rcu_preempt kthread starved for 10208 jiffies! g142749 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:26912 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </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: 22466 Comm: syz.5.4059 Not tainted 6.1.138-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
RIP: 0010:check_preemption_disabled+0x42/0x110 lib/smp_processor_id.c:55
Code: 65 8b 05 c1 c3 f2 75 65 8b 0d 62 19 f3 75 f7 c1 ff ff ff 7f 74 1f 65 48 8b 0c 25 28 00 00 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
RSP: 0018:ffffc90005007a98 EFLAGS: 00000246
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 32f15b0319c1f000
RDX: ffff888073a21dc0 RSI: ffffffff8abf0d80 RDI: ffffffff8abf0d40
RBP: 0000000000000002 R08: dffffc0000000000 R09: fffffbfff1bfd046
R10: fffffbfff1bfd046 R11: 1ffffffff1bfd045 R12: 1ffff92000a00f74
R13: 0000000000000000 R14: 0000000000000001 R15: dffffc0000000000
FS:  0000555588338500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b34116ff8 CR3: 000000007983a000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline]
 rcu_is_watching+0x11/0xa0 kernel/rcu/tree.c:721
 trace_x86_fpu_regs_activated arch/x86/include/asm/trace/fpu.h:57 [inline]
 fpregs_activate+0xa7/0x230 arch/x86/kernel/fpu/context.h:50
 fpregs_mark_activate+0x23/0x80 arch/x86/kernel/fpu/core.c:779
 restore_fpregs_from_user arch/x86/kernel/fpu/signal.c:330 [inline]
 __fpu_restore_sig arch/x86/kernel/fpu/signal.c:359 [inline]
 fpu__restore_sig+0x992/0x1190 arch/x86/kernel/fpu/signal.c:493
 restore_sigcontext arch/x86/kernel/signal.c:140 [inline]
 __ia32_sys_rt_sigreturn+0x649/0x790 arch/x86/kernel/signal.c:675
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb5e4d8ea27
Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 0a 00 00 00 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:00007fff54e2f318 EFLAGS: 00000206
RAX: 0000000000000000 RBX: 00007fb5e5c0b6c0 RCX: 00007fb5e4d8ea27
RDX: 0000000000000003 RSI: 0000000000020000 RDI: 00007fb5e5bec000
RBP: 0000000000000000 R08: 00000000ffffffff R09: 0000000000000000
R10: 0000000000021000 R11: 0000000000000206 R12: 00007fff54e2f470
R13: ffffffffffffffc0 R14: 0000000000001000 R15: 0000000000000000
 </TASK>
CPU: 0 PID: 22470 Comm: syz.3.4061 Not tainted 6.1.138-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
Code: 74 05 e8 ae e3 6d f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 36 5e 3e f7 65 8b 05 37 23 e9 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc9000557fbc0 EFLAGS: 00000206
RAX: 059b50c69fab1e00 RBX: 0000000000000a06 RCX: 059b50c69fab1e00
RDX: dffffc0000000000 RSI: ffffffff8a6bfe00 RDI: 0000000000000001
RBP: ffffc9000557fc50 R08: dffffc0000000000 R09: fffff52000ac0219
R10: fffff52000ac0219 R11: 1ffff92000ac0218 R12: dffffc0000000000
R13: 0000000000000020 R14: ffffc900056010c0 R15: 1ffff92000aaff78
FS:  00005555604e2500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b34118ff8 CR3: 0000000031acb000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __bpf_ringbuf_reserve+0x476/0x5a0 kernel/bpf/ringbuf.c:439
 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:464 [inline]
 bpf_ringbuf_reserve+0x58/0x70 kernel/bpf/ringbuf.c:456
 bpf_prog_a839990c72435f77+0x28/0x42
 bpf_dispatcher_nop_func include/linux/bpf.h:1001 [inline]
 __bpf_prog_run include/linux/filter.h:603 [inline]
 bpf_prog_run include/linux/filter.h:610 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline]
 bpf_trace_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324
 __bpf_trace_sys_enter+0x60/0x70 include/trace/events/syscalls.h:18
 __traceiter_sys_enter+0x26/0x40 include/trace/events/syscalls.h:18
 trace_sys_enter+0x6b/0x80 include/trace/events/syscalls.h:18
 syscall_trace_enter+0xf0/0x150 kernel/entry/common.c:81
 do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:77
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f989532ab39
Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25
RSP: 002b:00007ffdd28c8a00 EFLAGS: 00000246 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00000000001f19e8 RCX: 00007f989532ab39
RDX: 00007ffdd28c8a00 RSI: 00007ffdd28c8b30 RDI: 0000000000000011
RBP: 0000000000000032 R08: 0010cd833c4b3e79 R09: 00000009d28c928f
R10: 00007ffdd28c9090 R11: 0000000000000246 R12: 00007f98955b5fac
R13: 00007ffdd28c9090 R14: 00000000001f1a1a R15: 00007ffdd28c90b0
 </TASK>