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.0.17/6076:
 #0: ffffffff8dbc79a0 (rcu_read_lock_trace){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8dbc79a0 (rcu_read_lock_trace){....}-{0:0}, at: rcu_read_lock_trace+0x37/0x80 include/linux/rcupdate_trace.h:58

stack backtrace:
CPU: 1 UID: 0 PID: 6076 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 lockdep_rcu_suspicious+0x13f/0x1d0 kernel/locking/lockdep.c:6876
 get_callchain_entry+0x2b6/0x3c0 kernel/events/callchain.c:163
 get_perf_callchain+0xcb/0x830 kernel/events/callchain.c:231
 __bpf_get_stack+0x445/0xab0 kernel/bpf/stackmap.c:472
 ____bpf_get_stack kernel/bpf/stackmap.c:517 [inline]
 bpf_get_stack+0x33/0x50 kernel/bpf/stackmap.c:514
 ____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_aa1f08ea8b241262+0x46/0x4e
 bpf_dispatcher_nop_func include/linux/bpf.h:1378 [inline]
 __bpf_prog_run include/linux/filter.h:723 [inline]
 bpf_prog_run include/linux/filter.h:730 [inline]
 bpf_prog_run_pin_on_cpu+0x142/0x470 include/linux/filter.h:747
 bpf_prog_test_run_syscall+0x318/0x4c0 net/bpf/test_run.c:1639
 bpf_prog_test_run+0x2cd/0x340 kernel/bpf/syscall.c:4703
 __sys_bpf+0x5cb/0x920 kernel/bpf/syscall.c:6182
 __do_sys_bpf kernel/bpf/syscall.c:6274 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6272 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6272
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4cb3f5aeb9
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:00007ffdcd4bd018 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f4cb41d5fa0 RCX: 00007f4cb3f5aeb9
RDX: 0000000000000010 RSI: 0000200000000740 RDI: 000000000000000a
RBP: 00007f4cb3fc8c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4cb41d5fac R14: 00007f4cb41d5fa0 R15: 00007f4cb41d5fa0
 </TASK>