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Message-ID: <20240902114920.1534699-1-yun.zhou@windriver.com>
Date: Mon, 2 Sep 2024 19:49:20 +0800
From: Yun Zhou <yun.zhou@...driver.com>
To: <mcgrof@...nel.org>, <keescook@...omium.org>, <yzaikin@...gle.com>,
<rostedt@...dmis.org>, <mhiramat@...nel.org>,
<mathieu.desnoyers@...icios.com>, <yun.zhou@...driver.com>
CC: <linux-kernel@...r.kernel.org>, <linux-fsdevel@...r.kernel.org>,
<linux-trace-kernel@...r.kernel.org>
Subject: [PATCH] kernel: add pid_max to pid_namespace
Signed-off-by: Yun Zhou <yun.zhou@...driver.com>
---
include/linux/pid_namespace.h | 1 +
kernel/pid.c | 12 ++++++------
kernel/pid_namespace.c | 33 ++++++++++++++++++++++++++++-----
kernel/sysctl.c | 9 ---------
kernel/trace/pid_list.c | 2 +-
kernel/trace/trace.c | 2 +-
kernel/trace/trace.h | 2 --
7 files changed, 37 insertions(+), 24 deletions(-)
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index f9f9931e02d6..0e3c18f3cac5 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -27,6 +27,7 @@ struct pid_namespace {
struct idr idr;
struct rcu_head rcu;
unsigned int pid_allocated;
+ int pid_max;
struct task_struct *child_reaper;
struct kmem_cache *pid_cachep;
unsigned int level;
diff --git a/kernel/pid.c b/kernel/pid.c
index 6500ef956f2f..14da3f68ceed 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -59,8 +59,6 @@ struct pid init_struct_pid = {
}, }
};
-int pid_max = PID_MAX_DEFAULT;
-
#define RESERVED_PIDS 300
int pid_max_min = RESERVED_PIDS + 1;
@@ -74,6 +72,7 @@ int pid_max_max = PID_MAX_LIMIT;
*/
struct pid_namespace init_pid_ns = {
.ns.count = REFCOUNT_INIT(2),
+ .pid_max = PID_MAX_DEFAULT,
.idr = IDR_INIT(init_pid_ns.idr),
.pid_allocated = PIDNS_ADDING,
.level = 0,
@@ -194,7 +193,7 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *set_tid,
tid = set_tid[ns->level - i];
retval = -EINVAL;
- if (tid < 1 || tid >= pid_max)
+ if (tid < 1 || tid >= tmp->pid_max)
goto out_free;
/*
* Also fail if a PID != 1 is requested and
@@ -234,7 +233,7 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *set_tid,
* a partially initialized PID (see below).
*/
nr = idr_alloc_cyclic(&tmp->idr, NULL, pid_min,
- pid_max, GFP_ATOMIC);
+ tmp->pid_max, GFP_ATOMIC);
}
spin_unlock_irq(&pidmap_lock);
idr_preload_end();
@@ -651,11 +650,12 @@ void __init pid_idr_init(void)
BUILD_BUG_ON(PID_MAX_LIMIT >= PIDNS_ADDING);
/* bump default and minimum pid_max based on number of cpus */
- pid_max = min(pid_max_max, max_t(int, pid_max,
+ init_pid_ns.pid_max = min(pid_max_max, max_t(int, init_pid_ns.pid_max,
PIDS_PER_CPU_DEFAULT * num_possible_cpus()));
pid_max_min = max_t(int, pid_max_min,
PIDS_PER_CPU_MIN * num_possible_cpus());
- pr_info("pid_max: default: %u minimum: %u\n", pid_max, pid_max_min);
+ pr_info("pid_max: default: %u minimum: %u\n", init_pid_ns.pid_max,
+ pid_max_min);
idr_init(&init_pid_ns.idr);
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 3028b2218aa4..d6b3f34ecb25 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -110,6 +110,7 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns
ns->user_ns = get_user_ns(user_ns);
ns->ucounts = ucounts;
ns->pid_allocated = PIDNS_ADDING;
+ ns->pid_max = parent_pid_ns->pid_max;
#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
ns->memfd_noexec_scope = pidns_memfd_noexec_scope(parent_pid_ns);
#endif
@@ -295,20 +296,44 @@ static int pid_ns_ctl_handler(struct ctl_table *table, int write,
return ret;
}
+#endif /* CONFIG_CHECKPOINT_RESTORE */
+
+static int pid_max_ns_ctl_handler(struct ctl_table *table, int write,
+ void *buffer, size_t *lenp, loff_t *ppos)
+{
+ struct pid_namespace *pid_ns = task_active_pid_ns(current);
+
+ if (write && !checkpoint_restore_ns_capable(pid_ns->user_ns))
+ return -EPERM;
+
+ table->data = &pid_ns->pid_max;
+ if (pid_ns->parent)
+ table->extra2 = &pid_ns->parent->pid_max;
+
+ return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+}
-extern int pid_max;
static struct ctl_table pid_ns_ctl_table[] = {
+#ifdef CONFIG_CHECKPOINT_RESTORE
{
.procname = "ns_last_pid",
.maxlen = sizeof(int),
.mode = 0666, /* permissions are checked in the handler */
.proc_handler = pid_ns_ctl_handler,
.extra1 = SYSCTL_ZERO,
- .extra2 = &pid_max,
+ .extra2 = &init_pid_ns.pid_max,
+ },
+#endif /* CONFIG_CHECKPOINT_RESTORE */
+ {
+ .procname = "pid_max",
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = pid_max_ns_ctl_handler,
+ .extra1 = &pid_max_min,
+ .extra2 = &pid_max_max,
},
{ }
};
-#endif /* CONFIG_CHECKPOINT_RESTORE */
int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
{
@@ -465,9 +490,7 @@ static __init int pid_namespaces_init(void)
{
pid_ns_cachep = KMEM_CACHE(pid_namespace, SLAB_PANIC | SLAB_ACCOUNT);
-#ifdef CONFIG_CHECKPOINT_RESTORE
register_sysctl_init("kernel", pid_ns_ctl_table);
-#endif
register_pid_ns_sysctl_table_vm();
return 0;
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 157f7ce2942d..857bfdb39b15 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1809,15 +1809,6 @@ static struct ctl_table kern_table[] = {
.proc_handler = proc_dointvec,
},
#endif
- {
- .procname = "pid_max",
- .data = &pid_max,
- .maxlen = sizeof (int),
- .mode = 0644,
- .proc_handler = proc_dointvec_minmax,
- .extra1 = &pid_max_min,
- .extra2 = &pid_max_max,
- },
{
.procname = "panic_on_oops",
.data = &panic_on_oops,
diff --git a/kernel/trace/pid_list.c b/kernel/trace/pid_list.c
index 95106d02b32d..ef52820e6719 100644
--- a/kernel/trace/pid_list.c
+++ b/kernel/trace/pid_list.c
@@ -414,7 +414,7 @@ struct trace_pid_list *trace_pid_list_alloc(void)
int i;
/* According to linux/thread.h, pids can be no bigger that 30 bits */
- WARN_ON_ONCE(pid_max > (1 << 30));
+ WARN_ON_ONCE(init_pid_ns.pid_max > (1 << 30));
pid_list = kzalloc(sizeof(*pid_list), GFP_KERNEL);
if (!pid_list)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index fbcd3bafb93e..6295679ce16c 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5415,7 +5415,7 @@ int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
if (mask == TRACE_ITER_RECORD_TGID) {
if (!tgid_map) {
- tgid_map_max = pid_max;
+ tgid_map_max = init_pid_ns.pid_max;
map = kvcalloc(tgid_map_max + 1, sizeof(*tgid_map),
GFP_KERNEL);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index b7f4ea25a194..df61b1db86a2 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -700,8 +700,6 @@ extern unsigned long tracing_thresh;
/* PID filtering */
-extern int pid_max;
-
bool trace_find_filtered_pid(struct trace_pid_list *filtered_pids,
pid_t search_pid);
bool trace_ignore_this_task(struct trace_pid_list *filtered_pids,
--
2.27.0
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