From d10742025b3fc726c9a4b75d695ae8f01d289a25 Mon Sep 17 00:00:00 2001
From: Martin Liu <liumartin@google.com>
Date: Thu, 27 Jun 2024 15:17:05 +0000
Subject: [PATCH] lmkd: handle missing process' information case

When we get nothing from /proc/<PID>/status and /proc/<PID>/cmdline,
we should return NULL or False because this usually indicates the
process has already terminated. We should avoid attempting
to kill a non-existent process, as it's an unnecessary waste
of kill timeout.

Bug: 331612600
Test: give memory pressure to trigger LMKD
Change-Id: I468ff25012f9bb6fc842a7fad268ebcad0de4690
Signed-off-by: Martin Liu <liumartin@google.com>
---
 lmkd.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lmkd.cpp b/lmkd.cpp
index 2a0f69b..23373fb 100644
--- a/lmkd.cpp
+++ b/lmkd.cpp
@@ -1050,7 +1050,7 @@ static bool read_proc_status(int pid, char *buf, size_t buf_sz) {
 
     size = read_all(fd, buf, buf_sz - 1);
     close(fd);
-    if (size < 0) {
+    if (size <= 0) {
         return false;
     }
     buf[size] = 0;
@@ -1118,7 +1118,7 @@ static char *proc_get_name(int pid, char *buf, size_t buf_size) {
     }
     ret = read_all(fd, buf, buf_size - 1);
     close(fd);
-    if (ret < 0) {
+    if (ret <= 0) {
         return NULL;
     }
     buf[ret] = '\0';