powerpc/perf: Cap 64bit userspace backtraces to PERF_MAX_STACK_DEPTH

We cap 32bit userspace backtraces to PERF_MAX_STACK_DEPTH
(currently 127), but we forgot to do the same for 64bit backtraces.

Cc: stable@vger.kernel.org
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
index 2396dda..ead5535 100644 (file)
--- a/arch/powerpc/perf/callchain.c
+++ b/arch/powerpc/perf/callchain.c
@@ -243,7 +243,7 @@ static void perf_callchain_user_64(struct perf_callchain_entry *entry,
        sp = regs->gpr[1];
        perf_callchain_store(entry, next_ip);
 
-       for (;;) {
+       while (entry->nr < PERF_MAX_STACK_DEPTH) {
                fp = (unsigned long __user *) sp;
                if (!valid_user_sp(sp, 1) || read_user_stack_64(fp, &next_sp))
                        return;