On 7.12.22 г. 14:27 ч., nb wrote:
On 30.11.22 г. 13:22 ч., Pavel Tikhomirov wrote:
Add a sysctl kernel.freeze_cgroup_timeout (default value 30 * HZ).
If one writes FROZEN to freezer.state file and after a timeout of
kernel.freeze_cgroup_timeout one still reads FREEZING from freezer.state
file (meaning that kernel does not succeed to freeze cgroup processes
still) - let's print a warning with information about the problem, e.g.:
[ 7196.621368] Freeze of /test took 0 sec, due to unfreezable process
13732:bash, stack:
[ 7196.621396] [<ffffffffa2df9556>] retint_careful+0x14/0x32
[ 7196.621431] [<ffffffffffffffff>] 0xffffffffffffffff
The output includes:
- path to problematic freezer cgroup
- timeout in seconds
- unfeezable process pid, comm and stack
https://jira.sw.ru/browse/PSBM-142970
Signed-off-by: Pavel Tikhomirov <ptikhomi...@virtuozzo.com>
---
v3: use kmalloc for entries and freezer_cg_name + reformat
---
include/linux/sysctl.h | 2 +
kernel/cgroup/legacy_freezer.c | 71 ++++++++++++++++++++++++++++++++--
kernel/sysctl.c | 10 +++++
3 files changed, 80 insertions(+), 3 deletions(-)
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 8fd2d3c217c2..b641dd2bba82 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -188,6 +188,8 @@ struct ctl_path {
};
extern int trusted_exec;
+#define DEFAULT_FREEZE_TIMEOUT (30 * HZ)
+extern int sysctl_freeze_timeout;
extern int ve_allow_module_load;
diff --git a/kernel/cgroup/legacy_freezer.c
b/kernel/cgroup/legacy_freezer.c
index 08236798d173..eea2f0b924f1 100644
--- a/kernel/cgroup/legacy_freezer.c
+++ b/kernel/cgroup/legacy_freezer.c
@@ -22,6 +22,10 @@
#include <linux/freezer.h>
#include <linux/seq_file.h>
#include <linux/mutex.h>
+#include <linux/jiffies.h>
+#include <linux/ratelimit.h>
+#include <linux/stacktrace.h>
+#include <linux/sysctl.h>
/*
* A cgroup is freezing if any FREEZING flags are set.
FREEZING_SELF is
@@ -43,6 +47,7 @@ enum freezer_state_flags {
struct freezer {
struct cgroup_subsys_state css;
unsigned int state;
+ unsigned long freeze_jiffies;
};
static DEFINE_MUTEX(freezer_mutex);
@@ -225,6 +230,60 @@ static void freezer_fork(struct task_struct *task)
mutex_unlock(&freezer_mutex);
}
+#define MAX_STACK_TRACE_DEPTH 64
+
+static void check_freezer_timeout(struct cgroup_subsys_state *css,
+ struct task_struct *task)
+
+{
+ static DEFINE_RATELIMIT_STATE(freeze_timeout_rs,
+ DEFAULT_FREEZE_TIMEOUT, 1);
+ int __freeze_timeout = READ_ONCE(sysctl_freeze_timeout);
+ struct freezer *freezer = css_freezer(css);
+ unsigned long nr_entries;
+ unsigned long *entries;
+ char *freezer_cg_name;
+ pid_t tgid;
+ int i;
+
+ if (!freezer->freeze_jiffies ||
+ freezer->freeze_jiffies + __freeze_timeout > get_jiffies_64())
+ return;
Don't you want to execute the logic if freeze_jiffies + __freeze_timeout
is larger than get_jiffies_64() ? Because this means the timeout has
elapsed and you consider the freezer hung?
Ok, disregard it, the code is indeed correct.
<snip>
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