diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/stackmap.c | 2 | ||||
| -rw-r--r-- | kernel/events/callchain.c | 14 | ||||
| -rw-r--r-- | kernel/events/core.c | 5 |
3 files changed, 17 insertions, 4 deletions
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index a82d7605db3f..f1de5c1a2af6 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -99,7 +99,7 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr) if (err) goto free_smap; - err = get_callchain_buffers(); + err = get_callchain_buffers(sysctl_perf_event_max_stack); if (err) goto free_smap; diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index 179ef4640964..e9fdb5203de5 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -104,7 +104,7 @@ fail: return -ENOMEM; } -int get_callchain_buffers(void) +int get_callchain_buffers(int event_max_stack) { int err = 0; int count; @@ -121,6 +121,15 @@ int get_callchain_buffers(void) /* If the allocation failed, give up */ if (!callchain_cpus_entries) err = -ENOMEM; + /* + * If requesting per event more than the global cap, + * return a different error to help userspace figure + * this out. + * + * And also do it here so that we have &callchain_mutex held. + */ + if (event_max_stack > sysctl_perf_event_max_stack) + err = -EOVERFLOW; goto exit; } @@ -174,11 +183,12 @@ perf_callchain(struct perf_event *event, struct pt_regs *regs) bool user = !event->attr.exclude_callchain_user; /* Disallow cross-task user callchains. */ bool crosstask = event->ctx->task && event->ctx->task != current; + const u32 max_stack = event->attr.sample_max_stack; if (!kernel && !user) return NULL; - return get_perf_callchain(regs, 0, kernel, user, sysctl_perf_event_max_stack, crosstask, true); + return get_perf_callchain(regs, 0, kernel, user, max_stack, crosstask, true); } struct perf_callchain_entry * diff --git a/kernel/events/core.c b/kernel/events/core.c index 050a290c72c7..79363f298445 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8843,7 +8843,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, if (!event->parent) { if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { - err = get_callchain_buffers(); + err = get_callchain_buffers(attr->sample_max_stack); if (err) goto err_addr_filters; } @@ -9165,6 +9165,9 @@ SYSCALL_DEFINE5(perf_event_open, return -EINVAL; } + if (!attr.sample_max_stack) + attr.sample_max_stack = sysctl_perf_event_max_stack; + /* * In cgroup mode, the pid argument is used to pass the fd * opened to the cgroup directory in cgroupfs. The cpu argument |