From d0b2f91bede3bd5e3d24dd6803e56eee959c1797 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Thu, 20 Oct 2016 00:10:27 -0300 Subject: Linux-libre 4.8.2-gnu --- kernel/events/callchain.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'kernel/events/callchain.c') diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index 179ef4640..e9fdb5203 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 * -- cgit v1.2.3-54-g00ecf