Commit 454e3126 authored by Bernd Edlinger's avatar Bernd Edlinger Committed by Eric W. Biederman

kernel/kcmp.c: Use new infrastructure to fix deadlocks in execve

This changes kcmp_epoll_target to use the new exec_update_mutex
instead of cred_guard_mutex.

This should be safe, as the credentials are only used for reading,
and furthermore ->mm and ->sighand are updated on execve,
but only under the new exec_update_mutex.
Signed-off-by: default avatarBernd Edlinger <bernd.edlinger@hotmail.de>
Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
parent aa884c11
...@@ -173,8 +173,8 @@ SYSCALL_DEFINE5(kcmp, pid_t, pid1, pid_t, pid2, int, type, ...@@ -173,8 +173,8 @@ SYSCALL_DEFINE5(kcmp, pid_t, pid1, pid_t, pid2, int, type,
/* /*
* One should have enough rights to inspect task details. * One should have enough rights to inspect task details.
*/ */
ret = kcmp_lock(&task1->signal->cred_guard_mutex, ret = kcmp_lock(&task1->signal->exec_update_mutex,
&task2->signal->cred_guard_mutex); &task2->signal->exec_update_mutex);
if (ret) if (ret)
goto err; goto err;
if (!ptrace_may_access(task1, PTRACE_MODE_READ_REALCREDS) || if (!ptrace_may_access(task1, PTRACE_MODE_READ_REALCREDS) ||
...@@ -229,8 +229,8 @@ SYSCALL_DEFINE5(kcmp, pid_t, pid1, pid_t, pid2, int, type, ...@@ -229,8 +229,8 @@ SYSCALL_DEFINE5(kcmp, pid_t, pid1, pid_t, pid2, int, type,
} }
err_unlock: err_unlock:
kcmp_unlock(&task1->signal->cred_guard_mutex, kcmp_unlock(&task1->signal->exec_update_mutex,
&task2->signal->cred_guard_mutex); &task2->signal->exec_update_mutex);
err: err:
put_task_struct(task1); put_task_struct(task1);
put_task_struct(task2); put_task_struct(task2);
......
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