diff options
| -rw-r--r-- | fs/proc/base.c | 25 | ||||
| -rw-r--r-- | lib/fault-inject.c | 7 |
2 files changed, 15 insertions, 17 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index 7d795d28dd02..872a3f28bfe4 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1363,16 +1363,16 @@ static ssize_t proc_fail_nth_write(struct file *file, const char __user *buf, 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); - if (task != current) - return -EPERM; - err = kstrtouint_from_user(buf, count, 0, &n); - if (err) - return err; - current->fail_nth = n; + return count; } @@ -1386,11 +1386,10 @@ static ssize_t proc_fail_nth_read(struct file *file, char __user *buf, task = get_proc_task(file_inode(file)); if (!task) return -ESRCH; - put_task_struct(task); - if (task != current) - return -EPERM; - len = snprintf(numbuf, sizeof(numbuf), "%u\n", task->fail_nth); + 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; } @@ -3355,11 +3354,7 @@ 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), - /* - * Operations on the file check that the task is current, - * so we create it with 0666 to support testing under unprivileged user. - */ - REG("fail-nth", 0666, proc_fail_nth_operations), + REG("fail-nth", 0644, proc_fail_nth_operations), #endif #ifdef CONFIG_TASK_IO_ACCOUNTING ONE("io", S_IRUSR, proc_tid_io_accounting), diff --git a/lib/fault-inject.c b/lib/fault-inject.c index 09ac73c177fd..7d315fdb9f13 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -107,9 +107,12 @@ static inline bool fail_stacktrace(struct fault_attr *attr) bool should_fail(struct fault_attr *attr, ssize_t size) { - if (in_task() && current->fail_nth) { - if (--current->fail_nth == 0) + if (in_task()) { + unsigned int fail_nth = READ_ONCE(current->fail_nth); + + if (fail_nth && !WRITE_ONCE(current->fail_nth, fail_nth - 1)) goto fail; + return false; } |