perf/callchain: Force USER_DS when invoking perf_callchain_user()

[linux-2.6-microblaze.git] / kernel / events / callchain.c

diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index c04917c..1b2be63 100644 (file)
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -229,12 +229,18 @@ 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);
                }
        }