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authorBernd Edlinger <bernd.edlinger@hotmail.de>2020-03-20 21:27:24 +0100
committerEric W. Biederman <ebiederm@xmission.com>2020-03-25 10:04:01 -0500
commit2db9dbf71bf98d02a0bf33e798e5bfd2a9944696 (patch)
treeb63a4232ab077b356f26635dbb9bb971914933a8 /fs/proc
parent454e3126cb842388e22df6b3ac3da44062c00765 (diff)
proc: Use new infrastructure to fix deadlocks in execve
This changes lock_trace to use the new exec_update_mutex instead of cred_guard_mutex. This fixes possible deadlocks when the trace is accessing /proc/$pid/stack for instance. This should be safe, as the credentials are only used for reading, and task->mm is updated on execve under the new exec_update_mutex. Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/base.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index e7efe9d6f3d6..a278fda0458b 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -405,11 +405,11 @@ print0:
static int lock_trace(struct task_struct *task)
{
- int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
+ int err = mutex_lock_killable(&task->signal->exec_update_mutex);
if (err)
return err;
if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
- mutex_unlock(&task->signal->cred_guard_mutex);
+ mutex_unlock(&task->signal->exec_update_mutex);
return -EPERM;
}
return 0;
@@ -417,7 +417,7 @@ static int lock_trace(struct task_struct *task)
static void unlock_trace(struct task_struct *task)
{
- mutex_unlock(&task->signal->cred_guard_mutex);
+ mutex_unlock(&task->signal->exec_update_mutex);
}
#ifdef CONFIG_STACKTRACE