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-rw-r--r--fs/proc/base.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index c9e3f650f23c..08e3eccf9a12 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2706,9 +2706,16 @@ static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
{
struct task_io_accounting acct = task->ioac;
unsigned long flags;
+ int result;
- if (!ptrace_may_access(task, PTRACE_MODE_READ))
- return -EACCES;
+ result = mutex_lock_killable(&task->signal->cred_guard_mutex);
+ if (result)
+ return result;
+
+ if (!ptrace_may_access(task, PTRACE_MODE_READ)) {
+ result = -EACCES;
+ goto out_unlock;
+ }
if (whole && lock_task_sighand(task, &flags)) {
struct task_struct *t = task;
@@ -2719,7 +2726,7 @@ static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
unlock_task_sighand(task, &flags);
}
- return sprintf(buffer,
+ result = sprintf(buffer,
"rchar: %llu\n"
"wchar: %llu\n"
"syscr: %llu\n"
@@ -2734,6 +2741,9 @@ static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
(unsigned long long)acct.read_bytes,
(unsigned long long)acct.write_bytes,
(unsigned long long)acct.cancelled_write_bytes);
+out_unlock:
+ mutex_unlock(&task->signal->cred_guard_mutex);
+ return result;
}
static int proc_tid_io_accounting(struct task_struct *task, char *buffer)