From: Oleg Nesterov <oleg@redhat.com>
To: David Howells <dhowells@redhat.com>, Roland McGrath <roland@redhat.com>
Cc: linux-kernel@vger.kernel.org
Subject: Q: PTRACE_ATTACH && -EINTR
Date: Mon, 8 Jun 2009 18:12:04 +0200 [thread overview]
Message-ID: <20090608161204.GA3986@redhat.com> (raw)
I just realized that ->cred_exec_mutex added a user-visible change
which may confuse user-space.
ptrace_attach:
retval = mutex_lock_interruptible(&task->cred_exec_mutex);
if (retval < 0)
goto out;
This doesn't look good, we return -EINTR. Suppose that strace tries to
attach to all sub-threads and ptrace(PTRACE_ATTACH) returns -EINTR just
because the already traced thread sends SIGCHLD. Or tracer's sub-thread
does recalc_sigpending_and_wake().
I think we should at least do
retval = -ERESTARTSYS;
if (mutex_lock_interruptible(&task->cred_exec_mutex))
goto out;
Or even -ERESTARTNOINTR ? Or just mutex_lock() ?
Or ignore this problem since nobody complained?
Oleg.
next reply other threads:[~2009-06-08 16:16 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-08 16:12 Oleg Nesterov [this message]
2009-06-08 17:39 ` Q: PTRACE_ATTACH && -EINTR Roland McGrath
2009-06-08 18:36 ` Oleg Nesterov
2009-06-09 1:44 ` Roland McGrath
2009-06-10 13:11 ` Oleg Nesterov
2009-06-10 17:40 ` Roland McGrath
2009-06-19 0:38 ` [PATCH] cred_guard_mutex: do not return -EINTR to user-space Oleg Nesterov
2009-06-19 2:24 ` Roland McGrath
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