sparc64: Like x86 we should check current->mm during perf backtrace generation.
[ Upstream commit 08280e6c4c2e8049ac61d9e8e3536ec1df629c0d ]
If the MM is not active, only report the top-level PC. Do not try to
access the address space.
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index 28559ce..db344c4 100644
--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -1428,8 +1428,6 @@
{
unsigned long ufp;
- perf_callchain_store(entry, regs->tpc);
-
ufp = regs->u_regs[UREG_I6] + STACK_BIAS;
do {
struct sparc_stackf *usf, sf;
@@ -1450,8 +1448,6 @@
{
unsigned long ufp;
- perf_callchain_store(entry, regs->tpc);
-
ufp = regs->u_regs[UREG_I6] & 0xffffffffUL;
do {
struct sparc_stackf32 *usf, sf;
@@ -1470,6 +1466,11 @@
void
perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
{
+ perf_callchain_store(entry, regs->tpc);
+
+ if (!current->mm)
+ return;
+
flushw_user();
if (test_thread_flag(TIF_32BIT))
perf_callchain_user_32(entry, regs);