Apply after "[PATCH] Fix NULL ->nsproxy dereference in /proc/*/mounts".
Similar to get_task_mm(): get a reference to task's mnt namespace if any.
Suggested by Pavel Emelianov.
Signed-off-by: Alexey Dobriyan <[email protected]>
---
fs/proc/base.c | 15 ++-------------
include/linux/nsproxy.h | 1 +
kernel/nsproxy.c | 14 ++++++++++++++
3 files changed, 17 insertions(+), 13 deletions(-)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -370,13 +370,7 @@ static int mounts_open(struct inode *ino
int ret = -EINVAL;
if (task) {
- task_lock(task);
- if (task->nsproxy) {
- ns = task->nsproxy->mnt_ns;
- if (ns)
- get_mnt_ns(ns);
- }
- task_unlock(task);
+ ns = get_task_mnt_ns(task);
put_task_struct(task);
}
@@ -443,12 +437,7 @@ static int mountstats_open(struct inode
struct task_struct *task = get_proc_task(inode);
if (task) {
- task_lock(task);
- if (task->nsproxy)
- mnt_ns = task->nsproxy->mnt_ns;
- if (mnt_ns)
- get_mnt_ns(mnt_ns);
- task_unlock(task);
+ mnt_ns = get_task_mnt_ns(task);
put_task_struct(task);
}
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -35,6 +35,7 @@ struct nsproxy *dup_namespaces(struct ns
int copy_namespaces(int flags, struct task_struct *tsk);
void get_task_namespaces(struct task_struct *tsk);
void free_nsproxy(struct nsproxy *ns);
+struct mnt_namespace * get_task_mnt_ns(struct task_struct *tsk);
static inline void put_nsproxy(struct nsproxy *ns)
{
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -147,3 +147,17 @@ void free_nsproxy(struct nsproxy *ns)
put_pid_ns(ns->pid_ns);
kfree(ns);
}
+
+struct mnt_namespace * get_task_mnt_ns(struct task_struct *tsk)
+{
+ struct mnt_namespace *mnt_ns = NULL;
+
+ task_lock(tsk);
+ if (tsk->nsproxy)
+ mnt_ns = tsk->nsproxy->mnt_ns;
+ if (mnt_ns)
+ get_mnt_ns(mnt_ns);
+ task_unlock(tsk);
+
+ return mnt_ns;
+}
-
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