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.0.17/5949:
 #0: ffffffff8cd30000 (rcu_read_lock_trace){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8cd30000 (rcu_read_lock_trace){....}-{0:0}, at: rcu_read_lock_trace+0x37/0x70 include/linux/rcupdate_trace.h:57

stack backtrace:
CPU: 0 PID: 5949 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 lockdep_rcu_suspicious+0x1e1/0x300 kernel/locking/lockdep.c:6731
 get_callchain_entry+0x2a9/0x3c0 kernel/events/callchain.c:161
 get_perf_callchain+0xa3/0x4b0 kernel/events/callchain.c:187
 __bpf_get_stack+0x2d7/0x510 kernel/bpf/stackmap.c:435
 ____bpf_get_stack_raw_tp kernel/trace/bpf_trace.c:1917 [inline]
 bpf_get_stack_raw_tp+0x1a9/0x210 kernel/trace/bpf_trace.c:1907
 bpf_prog_b8a90dd1efcc4ad9+0x45/0x49
 bpf_dispatcher_nop_func include/linux/bpf.h:1223 [inline]
 __bpf_prog_run include/linux/filter.h:612 [inline]
 bpf_prog_run include/linux/filter.h:619 [inline]
 bpf_prog_run_pin_on_cpu+0x63/0x140 include/linux/filter.h:636
 bpf_prog_test_run_syscall+0x311/0x490 net/bpf/test_run.c:1501
 bpf_prog_test_run+0x321/0x390 kernel/bpf/syscall.c:4129
 __sys_bpf+0x440/0x800 kernel/bpf/syscall.c:5491
 __do_sys_bpf kernel/bpf/syscall.c:5577 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5575 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5575
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fbd3658ec29
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:00007ffee7ac9778 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007fbd367d5fa0 RCX: 00007fbd3658ec29
RDX: 000000000000000c RSI: 00002000000004c0 RDI: 000000000000000a
RBP: 00007fbd36611e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbd367d5fa0 R14: 00007fbd367d5fa0 R15: 0000000000000003
 </TASK>