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| author | KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> | 2010-10-27 15:34:08 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-27 18:03:12 -0700 |
| commit | 9b1bf12d5d51bca178dea21b04a0805e29d60cf1 (patch) | |
| tree | 902a2c0e5882a2152da59a589958d6426dc84643 /kernel | |
| parent | b84011508360d6885a9d95a235ec77d56f133377 (diff) | |
| download | linux-9b1bf12d5d51bca178dea21b04a0805e29d60cf1.tar.gz linux-9b1bf12d5d51bca178dea21b04a0805e29d60cf1.tar.bz2 linux-9b1bf12d5d51bca178dea21b04a0805e29d60cf1.zip | |
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.c | 4 | ||||
| -rw-r--r-- | kernel/fork.c | 2 | ||||
| -rw-r--r-- | kernel/ptrace.c | 4 |
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; } |