lmkd: Change error to warning when accessing oom_score_adj file
Occasionally processes are killed or crash while lmkd is trying to access
their oom_score_adj file. This is not necessarily an erroneous condition
and therefore should not be reported as an error. Demoting error to a
warning with a detailed message.
Bug: 72039129
Test: verified logcat output
Change-Id: I97444ba5198c02cb7f7ba03c3af12e4aad9d233e
diff --git a/lmkd/lmkd.c b/lmkd/lmkd.c
index 45fa863..8dd4587 100644
--- a/lmkd/lmkd.c
+++ b/lmkd/lmkd.c
@@ -20,6 +20,7 @@
#include <inttypes.h>
#include <sched.h>
#include <signal.h>
+#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <sys/cdefs.h>
@@ -267,24 +268,32 @@
return 0;
}
-static void writefilestring(const char *path, char *s) {
+/*
+ * Write a string to a file.
+ * Returns false if the file does not exist.
+ */
+static bool writefilestring(const char *path, const char *s,
+ bool err_if_missing) {
int fd = open(path, O_WRONLY | O_CLOEXEC);
- int len = strlen(s);
- int ret;
+ ssize_t len = strlen(s);
+ ssize_t ret;
if (fd < 0) {
- ALOGE("Error opening %s; errno=%d", path, errno);
- return;
+ if (err_if_missing) {
+ ALOGE("Error opening %s; errno=%d", path, errno);
+ }
+ return false;
}
- ret = write(fd, s, len);
+ ret = TEMP_FAILURE_RETRY(write(fd, s, len));
if (ret < 0) {
ALOGE("Error writing %s; errno=%d", path, errno);
} else if (ret < len) {
- ALOGE("Short write on %s; length=%d", path, ret);
+ ALOGE("Short write on %s; length=%zd", path, ret);
}
close(fd);
+ return true;
}
static void cmd_procprio(LMKD_CTRL_PACKET packet) {
@@ -304,7 +313,12 @@
snprintf(path, sizeof(path), "/proc/%d/oom_score_adj", params.pid);
snprintf(val, sizeof(val), "%d", params.oomadj);
- writefilestring(path, val);
+ if (!writefilestring(path, val, false)) {
+ ALOGW("Failed to open %s; errno=%d: process %d might have been killed",
+ path, errno, params.pid);
+ /* If this file does not exist the process is dead. */
+ return;
+ }
if (use_inkernel_interface)
return;
@@ -341,7 +355,7 @@
"/dev/memcg/apps/uid_%d/pid_%d/memory.soft_limit_in_bytes",
params.uid, params.pid);
snprintf(val, sizeof(val), "%d", soft_limit_mult * EIGHT_MEGA);
- writefilestring(path, val);
+ writefilestring(path, val, true);
procp = pid_lookup(params.pid);
if (!procp) {
@@ -408,8 +422,8 @@
strlcat(killpriostr, val, sizeof(killpriostr));
}
- writefilestring(INKERNEL_MINFREE_PATH, minfreestr);
- writefilestring(INKERNEL_ADJ_PATH, killpriostr);
+ writefilestring(INKERNEL_MINFREE_PATH, minfreestr, true);
+ writefilestring(INKERNEL_ADJ_PATH, killpriostr, true);
}
}