From: Tejun Heo <tj@kernel.org>
To: oleg@redhat.com, jan.kratochvil@redhat.com, vda.linux@googlemail.com
Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
akpm@linux-foundation.org, indan@nul.nu, roland@hack.frob.com,
Tejun Heo <tj@kernel.org>, Roland McGrath <roland@redhat.com>
Subject: [PATCH 08/20] ptrace: Participate in group stop from ptrace_stop() iff the task is trapping for group stop
Date: Wed, 23 Mar 2011 11:05:54 +0100 [thread overview]
Message-ID: <1300874766-12941-9-git-send-email-tj@kernel.org> (raw)
In-Reply-To: <1300874766-12941-1-git-send-email-tj@kernel.org>
Currently, ptrace_stop() unconditionally participates in group stop
bookkeeping. This is unnecessary and inaccurate. Make it only
participate if the task is trapping for group stop - ie. if @why is
CLD_STOPPED. As ptrace_stop() currently is not used when trapping for
group stop, this equals to disabling group stop participation from
ptrace_stop().
A visible behavior change is increased likelihood of delayed group
stop completion if the thread group contains one or more ptraced
tasks.
This is to preapre for further cleanup of the interaction between
group stop and ptrace.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
---
kernel/signal.c | 9 ++++++---
1 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/kernel/signal.c b/kernel/signal.c
index a2e7a65..9f36dd2 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1694,10 +1694,13 @@ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
}
/*
- * If there is a group stop in progress,
- * we must participate in the bookkeeping.
+ * If @why is CLD_STOPPED, we're trapping to participate in a group
+ * stop. Do the bookkeeping. Note that if SIGCONT was delievered
+ * while siglock was released for the arch hook, PENDING could be
+ * clear now. We act as if SIGCONT is received after TASK_TRACED
+ * is entered - ignore it.
*/
- if (current->group_stop & GROUP_STOP_PENDING)
+ if (why == CLD_STOPPED && (current->group_stop & GROUP_STOP_PENDING))
task_participate_group_stop(current);
current->last_siginfo = info;
--
1.7.1
next prev parent reply other threads:[~2011-03-23 10:07 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-23 10:05 [PATCHSET] ptrace,signal: Improve ptrace and job control interaction Tejun Heo
2011-03-23 10:05 ` [PATCH 01/20] signal: Fix SIGCONT notification code Tejun Heo
2011-03-23 10:05 ` [PATCH 02/20] ptrace: Remove the extra wake_up_state() from ptrace_detach() Tejun Heo
2011-03-23 10:05 ` [PATCH 03/20] signal: Remove superflous try_to_freeze() loop in do_signal_stop() Tejun Heo
2011-03-23 10:05 ` [PATCH 04/20] ptrace: Kill tracehook_notify_jctl() Tejun Heo
2011-03-23 10:05 ` [PATCH 05/20] ptrace: Add @why to ptrace_stop() Tejun Heo
2011-03-23 10:05 ` [PATCH 06/20] signal: Fix premature completion of group stop when interfered by ptrace Tejun Heo
2011-03-23 10:05 ` [PATCH 07/20] signal: Use GROUP_STOP_PENDING to stop once for a single group stop Tejun Heo
2011-03-23 10:05 ` Tejun Heo [this message]
2011-03-23 10:05 ` [PATCH 09/20] ptrace: Make do_signal_stop() use ptrace_stop() if the task is being ptraced Tejun Heo
2011-03-23 10:05 ` [PATCH 10/20] ptrace: Clean transitions between TASK_STOPPED and TRACED Tejun Heo
2011-03-23 10:05 ` [PATCH 11/20] ptrace: Collapse ptrace_untrace() into __ptrace_unlink() Tejun Heo
2011-03-23 10:05 ` [PATCH 12/20] ptrace: Always put ptracee into appropriate execution state Tejun Heo
2011-03-23 10:05 ` [PATCH 13/20] job control: Don't set group_stop exit_code if re-entering job control stop Tejun Heo
2011-03-23 10:06 ` [PATCH 14/20] job control: Small reorganization of wait_consider_task() Tejun Heo
2011-03-23 10:06 ` [PATCH 15/20] job control: Fix ptracer wait(2) hang and explain notask_error clearing Tejun Heo
2011-03-23 10:06 ` [PATCH 16/20] job control: Allow access to job control events through ptracees Tejun Heo
2011-03-23 10:06 ` [PATCH 17/20] job control: Add @for_ptrace to do_notify_parent_cldstop() Tejun Heo
2011-03-23 10:06 ` [PATCH 18/20] job control: Job control stop notifications should always go to the real parent Tejun Heo
2011-03-23 10:06 ` [PATCH 19/20] job control: Notify the real parent of job control events regardless of ptrace Tejun Heo
2011-03-23 10:06 ` [PATCH 20/20] job control: Don't send duplicate job control stop notification while ptraced Tejun Heo
2011-03-23 18:38 ` [PATCHSET] ptrace,signal: Improve ptrace and job control interaction Oleg Nesterov
2011-03-25 14:26 ` Tejun Heo
2011-03-26 18:25 ` Oleg Nesterov
2011-03-28 8:58 ` Tejun Heo
2011-03-28 12:14 ` Oleg Nesterov
2011-03-28 15:21 ` Tejun Heo
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