diff options
Diffstat (limited to 'kernel/events/callchain.c')
| -rw-r--r-- | kernel/events/callchain.c | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index e9fdb5203de5..c265f1c3ae50 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -117,23 +117,20 @@ int get_callchain_buffers(int event_max_stack) goto exit; } - if (count > 1) { - /* 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; + /* + * 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; } - err = alloc_callchain_buffers(); + if (count == 1) + err = alloc_callchain_buffers(); exit: if (err) atomic_dec(&nr_callchain_events); @@ -227,12 +224,18 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user, } if (regs) { + mm_segment_t fs; + if (crosstask) goto exit_put; if (add_mark) perf_callchain_store_context(&ctx, PERF_CONTEXT_USER); + + fs = get_fs(); + set_fs(USER_DS); perf_callchain_user(&ctx, regs); + set_fs(fs); } } |