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authorTejun Heo <tj@kernel.org>2011-06-02 11:14:00 +0200
committerOleg Nesterov <oleg@redhat.com>2011-06-04 18:17:11 +0200
commit7dd3db54e77d21eb95e145f19ba53f68250d0e73 (patch)
tree628e44b22e6fbf2828cf2c533c41b3d24f3e3ec9 /kernel/ptrace.c
parent6dfca32984237a8a011b5bf367e53341a265b2a4 (diff)
downloadlwn-7dd3db54e77d21eb95e145f19ba53f68250d0e73.tar.gz
lwn-7dd3db54e77d21eb95e145f19ba53f68250d0e73.zip
job control: introduce task_set_jobctl_pending()
task->jobctl currently hosts JOBCTL_STOP_PENDING and will host TRAP pending bits too. Setting pending conditions on a dying task may make the task unkillable. Currently, each setting site is responsible for checking for the condition but with to-be-added job control traps this becomes too fragile. This patch adds task_set_jobctl_pending() which should be used when setting task->jobctl bits to schedule a stop or trap. The function performs the followings to ease setting pending bits. * Sanity checks. * If fatal signal is pending or PF_EXITING is set, no bit is set. * STOP_SIGMASK is automatically cleared if new value is being set. do_signal_stop() and ptrace_attach() are updated to use task_set_jobctl_pending() instead of setting STOP_PENDING explicitly. The surrounding structures around setting are changed to fit task_set_jobctl_pending() better but there should be no userland visible behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Diffstat (limited to 'kernel/ptrace.c')
-rw-r--r--kernel/ptrace.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index eb191116edf7..0c37d999c8b8 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -256,10 +256,10 @@ static int ptrace_attach(struct task_struct *task)
* The following task_is_stopped() test is safe as both transitions
* in and out of STOPPED are protected by siglock.
*/
- if (task_is_stopped(task)) {
- task->jobctl |= JOBCTL_STOP_PENDING | JOBCTL_TRAPPING;
+ if (task_is_stopped(task) &&
+ task_set_jobctl_pending(task,
+ JOBCTL_STOP_PENDING | JOBCTL_TRAPPING))
signal_wake_up(task, 1);
- }
spin_unlock(&task->sighand->siglock);