x86, perf: Check that current->mm is alive before getting user callchain

[pandora-kernel.git] / arch / x86 / kernel / cpu / perf_event.c

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 4ee3abf..cfa62ec 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1900,6 +1900,9 @@ perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
 
        perf_callchain_store(entry, regs->ip);
 
+       if (!current->mm)
+               return;
+
        if (perf_callchain_user32(regs, entry))
                return;