diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 3 | ||||
| -rw-r--r-- | kernel/events/core.c | 18 |
2 files changed, 21 insertions, 0 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 8d6979db48d8..cd14e70f2d07 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4962,6 +4962,9 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn env->prog->has_callchain_buf = true; } + if (func_id == BPF_FUNC_get_stackid || func_id == BPF_FUNC_get_stack) + env->prog->call_get_stack = true; + if (changes_data) clear_all_pkt_pointers(env); return 0; diff --git a/kernel/events/core.c b/kernel/events/core.c index 856d98c36f56..ddcfd2fb5cc5 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -9544,6 +9544,24 @@ static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd) if (IS_ERR(prog)) return PTR_ERR(prog); + if (event->attr.precise_ip && + prog->call_get_stack && + (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) || + event->attr.exclude_callchain_kernel || + event->attr.exclude_callchain_user)) { + /* + * On perf_event with precise_ip, calling bpf_get_stack() + * may trigger unwinder warnings and occasional crashes. + * bpf_get_[stack|stackid] works around this issue by using + * callchain attached to perf_sample_data. If the + * perf_event does not full (kernel and user) callchain + * attached to perf_sample_data, do not allow attaching BPF + * program that calls bpf_get_[stack|stackid]. + */ + bpf_prog_put(prog); + return -EPROTO; + } + event->prog = prog; event->orig_overflow_handler = READ_ONCE(event->overflow_handler); WRITE_ONCE(event->overflow_handler, bpf_overflow_handler); |