[PATCH 3.12 047/142] powerpc/perf: Cap 64bit userspace backtraces to PERF_MAX_STACK_DEPTH

From: Jiri Slaby
Date: Sat May 16 2015 - 04:24:41 EST


From: Anton Blanchard <anton@xxxxxxxxx>

3.12-stable 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@xxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
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 2396dda282cd..ead55351b254 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;
--
2.3.7

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/