[PATCH 3.4 042/146] powerpc/perf: Cap 64bit userspace backtraces to PERF_MAX_STACK_DEPTH

lizf
2015-09-15T09:48:43Z

From: Anton Blanchard <anton@samba.org>

3.4.109-rc1 review patch. If anyone has any objections, please let me know.

------------------

commit 9a5cbce421a283e6aea3c4007f141735bf9da8c3 upstream.

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

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
arch/powerpc/perf/callchain.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
index e8a18d1..a9bd794 100644
--- 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;
--
1.9.1