syzbot

=============================
WARNING: suspicious RCU usage
syzkaller #0 Not tainted
-----------------------------
kernel/events/callchain.c:163 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
1 lock held by syz.0.17/5994:
 #0: ffffffff8e13d500 (rcu_read_lock_trace){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e13d500 (rcu_read_lock_trace){....}-{0:0}, at: rcu_read_lock_trace+0x38/0x80 include/linux/rcupdate_trace.h:58

stack backtrace:
CPU: 0 UID: 0 PID: 5994 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 lockdep_rcu_suspicious+0x140/0x1d0 kernel/locking/lockdep.c:6876
 get_callchain_entry+0x2b6/0x3c0 kernel/events/callchain.c:163
 get_perf_callchain+0xb3/0x6f0 kernel/events/callchain.c:231
 __bpf_get_stack+0x3fa/0xa60 kernel/bpf/stackmap.c:454
 ____bpf_get_stack kernel/bpf/stackmap.c:499 [inline]
 bpf_get_stack+0x33/0x50 kernel/bpf/stackmap.c:496
 ____bpf_get_stack_raw_tp kernel/trace/bpf_trace.c:1653 [inline]
 bpf_get_stack_raw_tp+0x1a9/0x220 kernel/trace/bpf_trace.c:1643
 bpf_prog_e8e6327ccf46c9a7+0x46/0x4e
 bpf_dispatcher_nop_func include/linux/bpf.h:1350 [inline]
 __bpf_prog_run include/linux/filter.h:721 [inline]
 bpf_prog_run include/linux/filter.h:728 [inline]
 bpf_prog_run_pin_on_cpu+0x143/0x470 include/linux/filter.h:745
 bpf_prog_test_run_syscall+0x312/0x4b0 net/bpf/test_run.c:1573
 bpf_prog_test_run+0x2c7/0x340 kernel/bpf/syscall.c:4673
 __sys_bpf+0x562/0x860 kernel/bpf/syscall.c:6152
 __do_sys_bpf kernel/bpf/syscall.c:6244 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6242 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6242
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8c7838eec9
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:00007fff6f70fd68 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f8c785e5fa0 RCX: 00007f8c7838eec9
RDX: 000000000000000c RSI: 00002000000004c0 RDI: 000000000000000a
RBP: 00007f8c78411f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8c785e5fa0 R14: 00007f8c785e5fa0 R15: 0000000000000003
 </TASK>