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-rw-r--r--fs/proc/base.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index f1e1927ccd48..719c2e943ea1 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1355,6 +1355,49 @@ static const struct file_operations proc_fault_inject_operations = {
.write = proc_fault_inject_write,
.llseek = generic_file_llseek,
};
+
+static ssize_t proc_fail_nth_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct task_struct *task;
+ int err;
+ unsigned int n;
+
+ err = kstrtouint_from_user(buf, count, 0, &n);
+ if (err)
+ return err;
+
+ task = get_proc_task(file_inode(file));
+ if (!task)
+ return -ESRCH;
+ WRITE_ONCE(task->fail_nth, n);
+ put_task_struct(task);
+
+ return count;
+}
+
+static ssize_t proc_fail_nth_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct task_struct *task;
+ char numbuf[PROC_NUMBUF];
+ ssize_t len;
+
+ task = get_proc_task(file_inode(file));
+ if (!task)
+ return -ESRCH;
+ len = snprintf(numbuf, sizeof(numbuf), "%u\n",
+ READ_ONCE(task->fail_nth));
+ len = simple_read_from_buffer(buf, count, ppos, numbuf, len);
+ put_task_struct(task);
+
+ return len;
+}
+
+static const struct file_operations proc_fail_nth_operations = {
+ .read = proc_fail_nth_read,
+ .write = proc_fail_nth_write,
+};
#endif
@@ -2919,6 +2962,7 @@ static const struct pid_entry tgid_base_stuff[] = {
#endif
#ifdef CONFIG_FAULT_INJECTION
REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
+ REG("fail-nth", 0644, proc_fail_nth_operations),
#endif
#ifdef CONFIG_ELF_CORE
REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
@@ -3311,6 +3355,7 @@ static const struct pid_entry tid_base_stuff[] = {
#endif
#ifdef CONFIG_FAULT_INJECTION
REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
+ REG("fail-nth", 0644, proc_fail_nth_operations),
#endif
#ifdef CONFIG_TASK_IO_ACCOUNTING
ONE("io", S_IRUSR, proc_tid_io_accounting),