[PATCH 5.4 210/434] s390: add error handling to perf_callchain_kernel

Greg Kroah-Hartman
2019-12-29T17:49:51Z

From: Ilya Leoshkevich <iii@linux.ibm.com>

[ Upstream commit effb83ccc83a97dbbe5214f4c443522719f05f3a ]

perf_callchain_kernel stops neither when it encounters a garbage
address, nor when it runs out of space. Fix both issues using x86
version as an inspiration.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/s390/kernel/perf_event.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/s390/kernel/perf_event.c b/arch/s390/kernel/perf_event.c
index fcb6c2e92b07..1e75cc983546 100644
--- a/arch/s390/kernel/perf_event.c
+++ b/arch/s390/kernel/perf_event.c
@@ -224,9 +224,13 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
struct pt_regs *regs)
{
struct unwind_state state;
+ unsigned long addr;

- unwind_for_each_frame(&state, current, regs, 0)
- perf_callchain_store(entry, state.ip);
+ unwind_for_each_frame(&state, current, regs, 0) {
+ addr = unwind_get_return_address(&state);
+ if (!addr || perf_callchain_store(entry, addr))
+ return;
+ }
}

/* Perf definitions for PMU event attributes in sysfs */
--
2.20.1