syzbot

=============================
WARNING: suspicious RCU usage
syzkaller #0 Not tainted
-----------------------------
kernel/events/callchain.c:161 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.0.17/4423:
 #0: ffffffff8cb2b420 (rcu_read_lock_trace){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2b420 (rcu_read_lock_trace){....}-{0:0}, at: rcu_read_lock_trace+0x37/0x70 include/linux/rcupdate_trace.h:57

stack backtrace:
CPU: 1 PID: 4423 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 lockdep_rcu_suspicious+0x1dd/0x300 kernel/locking/lockdep.c:6611
 get_callchain_entry+0x2a5/0x3b0 kernel/events/callchain.c:161
 get_perf_callchain+0xc4/0x490 kernel/events/callchain.c:191
 __bpf_get_stack+0x2de/0x520 kernel/bpf/stackmap.c:438
 ____bpf_get_stack_raw_tp kernel/trace/bpf_trace.c:1880 [inline]
 bpf_get_stack_raw_tp+0x189/0x1c0 kernel/trace/bpf_trace.c:1870
 bpf_prog_14d9fb3786f83342+0x3d/0x41
 bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline]
 __bpf_prog_run include/linux/filter.h:607 [inline]
 bpf_prog_run include/linux/filter.h:614 [inline]
 bpf_prog_run_pin_on_cpu+0x64/0x150 include/linux/filter.h:631
 bpf_prog_test_run_syscall+0x313/0x4a0 net/bpf/test_run.c:1650
 bpf_prog_test_run+0x31e/0x390 kernel/bpf/syscall.c:3695
 __sys_bpf+0x62b/0x780 kernel/bpf/syscall.c:5048
 __do_sys_bpf kernel/bpf/syscall.c:5134 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5132 [inline]
 __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5132
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f1aff39acb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe8a350b38 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f1aff615fa0 RCX: 00007f1aff39acb9
RDX: 000000000000000c RSI: 00002000000004c0 RDI: 000000000000000a
RBP: 00007f1aff408bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1aff615fac R14: 00007f1aff615fa0 R15: 00007f1aff615fa0
 </TASK>