============================= 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.1.340/6873: #0: ffffffff8e7e44d8 (rcu_tasks_trace_srcu_struct){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:305 [inline] #0: ffffffff8e7e44d8 (rcu_tasks_trace_srcu_struct){....}-{0:0}, at: rcu_read_lock_trace include/linux/rcupdate_trace.h:100 [inline] #0: ffffffff8e7e44d8 (rcu_tasks_trace_srcu_struct){....}-{0:0}, at: bpf_prog_test_run_syscall+0x301/0xad0 net/bpf/test_run.c:1672 stack backtrace: CPU: 2 UID: 0 PID: 6873 Comm: syz.1.340 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 lockdep_rcu_suspicious.cold+0x4f/0xb1 kernel/locking/lockdep.c:6876 get_callchain_entry+0x278/0x3f0 kernel/events/callchain.c:163 get_perf_callchain+0x2d6/0x9c0 kernel/events/callchain.c:231 __bpf_get_stack+0x531/0xa90 kernel/bpf/stackmap.c:472 ____bpf_get_stack kernel/bpf/stackmap.c:517 [inline] bpf_get_stack+0x32/0x40 kernel/bpf/stackmap.c:514 ____bpf_get_stack_raw_tp kernel/trace/bpf_trace.c:1661 [inline] bpf_get_stack_raw_tp+0x1dd/0x280 kernel/trace/bpf_trace.c:1651 bpf_prog_42db8cfdf50901c9+0x46/0x4e bpf_dispatcher_nop_func include/linux/bpf.h:1402 [inline] __bpf_prog_run include/linux/filter.h:722 [inline] bpf_prog_run include/linux/filter.h:729 [inline] bpf_prog_run_pin_on_cpu include/linux/filter.h:746 [inline] bpf_prog_test_run_syscall+0x4b1/0xad0 net/bpf/test_run.c:1673 bpf_prog_test_run kernel/bpf/syscall.c:4742 [inline] __sys_bpf+0x1725/0x4b90 kernel/bpf/syscall.c:6266 __do_sys_bpf kernel/bpf/syscall.c:6361 [inline] __se_sys_bpf kernel/bpf/syscall.c:6359 [inline] __ia32_sys_bpf+0x79/0xf0 kernel/bpf/syscall.c:6359 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe7/0x950 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf703efcc Code: d2 74 05 c1 e8 0c 89 02 8b 5d fc 31 c0 c9 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 2e 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 58 b8 RSP: 002b:00000000f542d50c EFLAGS: 00000292 ORIG_RAX: 0000000000000165 RAX: ffffffffffffffda RBX: 000000000000000a RCX: 00000000800004c0 RDX: 000000000000000c RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess): 0: d2 74 05 c1 shlb %cl,-0x3f(%rbp,%rax,1) 4: e8 0c 89 02 8b call 0x8b028915 9: 5d pop %rbp a: fc cld b: 31 c0 xor %eax,%eax d: c9 leave e: c3 ret f: 90 nop 10: 90 nop 11: 90 nop 12: 90 nop 13: 90 nop 14: 90 nop 15: 90 nop 16: 90 nop 17: 90 nop 18: 90 nop 19: 90 nop 1a: 90 nop 1b: 90 nop 1c: 90 nop 1d: 90 nop 1e: 0f 1f 00 nopl (%rax) 21: 51 push %rcx 22: 52 push %rdx 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 ret 2e: 90 nop 2f: 2e 8d b4 26 00 00 00 cs lea 0x0(%rsi,%riz,1),%esi 36: 00 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 3e: 58 pop %rax 3f: b8 .byte 0xb8