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cgroup-util: kill also threads 

It's possible for a zombie process to have live threads. These are not listed
in /sys in "cgroup.procs" for cgroupsv2, but they show up in
"cgroup.threads" (cgroupv2) or "tasks" (cgroupv1) nodes. When killing a
cgroup (v2 only) with SIGKILL, let's also kill threads after killing processes,
so the live threads of a zombie get killed too.

Closes #12262.
This commit is contained in:
Topi Miettinen 2019-05-20 12:20:58 +03:00 committed by Lennart Poettering
parent 0127b1a05e
commit e48fcfef06
1 changed files with 35 additions and 5 deletions
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40
src/basic/cgroup-util.c
View File

@ -43,14 +43,14 @@
#include "unit-name.h"
#include "user-util.h"
int cg_enumerate_processes(const char *controller, const char *path, FILE **_f) {
static int cg_enumerate_items(const char *controller, const char *path, FILE **_f, const char *item) {
_cleanup_free_ char *fs = NULL;
FILE *f;
int r;
assert(_f);
r = cg_get_path(controller, path, "cgroup.procs", &fs);
r = cg_get_path(controller, path, item, &fs);
if (r < 0)
return r;
@ -62,6 +62,10 @@ int cg_enumerate_processes(const char *controller, const char *path, FILE **_f)
return 0;
}
int cg_enumerate_processes(const char *controller, const char *path, FILE **_f) {
return cg_enumerate_items(controller, path, _f, "cgroup.procs");
}
int cg_read_pid(FILE *f, pid_t *_pid) {
unsigned long ul;
@ -221,14 +225,15 @@ int cg_rmdir(const char *controller, const char *path) {
return 0;
}
int cg_kill(
static int cg_kill_items(
const char *controller,
const char *path,
int sig,
CGroupFlags flags,
Set *s,
cg_kill_log_func_t log_kill,
void *userdata) {
void *userdata,
const char *item) {
_cleanup_set_free_ Set *allocated_set = NULL;
bool done = false;
@ -259,7 +264,7 @@ int cg_kill(
pid_t pid = 0;
done = true;
r = cg_enumerate_processes(controller, path, &f);
r = cg_enumerate_items(controller, path, &f, item);
if (r < 0) {
if (ret >= 0 && r != -ENOENT)
return r;
@ -322,6 +327,31 @@ int cg_kill(
return ret;
}
int cg_kill(
const char *controller,
const char *path,
int sig,
CGroupFlags flags,
Set *s,
cg_kill_log_func_t log_kill,
void *userdata) {
int r;
r = cg_kill_items(controller, path, sig, flags, s, log_kill, userdata, "cgroup.procs");
if (r < 0 || sig != SIGKILL)
return r;
/* Only in case of killing with SIGKILL and when using cgroupsv2, kill remaining threads manually as
a workaround for kernel bug. It was fixed in 5.2-rc5 (c03cd7738a83). */
r = cg_unified_controller(controller);
if (r < 0)
return r;
if (r == 0) /* doesn't apply to legacy hierarchy */
return 0;
return cg_kill_items(controller, path, sig, flags, s, log_kill, userdata, "cgroup.threads");
}
int cg_kill_recursive(
const char *controller,
const char *path,