sparc64: Like x86 we should check current->mm during perf backtrace g…

…eneration. 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 <[email protected]>
syzer · Oct 15, 2012 · 08280e6 · 08280e6
1 parent ddffeb8
commit 08280e6
Showing 1 changed file with 5 additions and 4 deletions.
diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
@@ -1738,8 +1738,6 @@ static void perf_callchain_user_64(struct perf_callchain_entry *entry,
 {
 	unsigned long ufp;
 
-	perf_callchain_store(entry, regs->tpc);
-
 	ufp = regs->u_regs[UREG_I6] + STACK_BIAS;
 	do {
 		struct sparc_stackf *usf, sf;
@@ -1760,8 +1758,6 @@ static void perf_callchain_user_32(struct perf_callchain_entry *entry,
 {
 	unsigned long ufp;
 
-	perf_callchain_store(entry, regs->tpc);
-
 	ufp = regs->u_regs[UREG_I6] & 0xffffffffUL;
 	do {
 		struct sparc_stackf32 *usf, sf;
@@ -1780,6 +1776,11 @@ static void perf_callchain_user_32(struct perf_callchain_entry *entry,
 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);