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authorKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>2010-10-27 15:34:08 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-10-27 18:03:12 -0700
commit9b1bf12d5d51bca178dea21b04a0805e29d60cf1 (patch)
tree902a2c0e5882a2152da59a589958d6426dc84643 /kernel
parentb84011508360d6885a9d95a235ec77d56f133377 (diff)
signals: move cred_guard_mutex from task_struct to signal_struct
Oleg Nesterov pointed out we have to prevent multiple-threads-inside-exec itself and we can reuse ->cred_guard_mutex for it. Yes, concurrent execve() has no worth. Let's move ->cred_guard_mutex from task_struct to signal_struct. It naturally prevent multiple-threads-inside-exec. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cred.c4
-rw-r--r--kernel/fork.c2
-rw-r--r--kernel/ptrace.c4
3 files changed, 5 insertions, 5 deletions
diff --git a/kernel/cred.c b/kernel/cred.c
index 9a3e22641fe7..6a1aa004e376 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -325,7 +325,7 @@ EXPORT_SYMBOL(prepare_creds);
/*
* Prepare credentials for current to perform an execve()
- * - The caller must hold current->cred_guard_mutex
+ * - The caller must hold ->cred_guard_mutex
*/
struct cred *prepare_exec_creds(void)
{
@@ -384,8 +384,6 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags)
struct cred *new;
int ret;
- mutex_init(&p->cred_guard_mutex);
-
if (
#ifdef CONFIG_KEYS
!p->cred->thread_keyring &&
diff --git a/kernel/fork.c b/kernel/fork.c
index e87aaaaf5131..3b159c5991b7 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -908,6 +908,8 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
sig->oom_adj = current->signal->oom_adj;
sig->oom_score_adj = current->signal->oom_score_adj;
+ mutex_init(&sig->cred_guard_mutex);
+
return 0;
}
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index ea7ce0215cd1..99bbaa3e5b0d 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -181,7 +181,7 @@ int ptrace_attach(struct task_struct *task)
* under ptrace.
*/
retval = -ERESTARTNOINTR;
- if (mutex_lock_interruptible(&task->cred_guard_mutex))
+ if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
goto out;
task_lock(task);
@@ -208,7 +208,7 @@ int ptrace_attach(struct task_struct *task)
unlock_tasklist:
write_unlock_irq(&tasklist_lock);
unlock_creds:
- mutex_unlock(&task->cred_guard_mutex);
+ mutex_unlock(&task->signal->cred_guard_mutex);
out:
return retval;
}

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