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| author | Tejun Heo <tj@kernel.org> | 2011-06-02 11:14:00 +0200 |
|---|---|---|
| committer | Oleg Nesterov <oleg@redhat.com> | 2011-06-04 18:17:11 +0200 |
| commit | 7dd3db54e77d21eb95e145f19ba53f68250d0e73 (patch) | |
| tree | 628e44b22e6fbf2828cf2c533c41b3d24f3e3ec9 /kernel/ptrace.c | |
| parent | 6dfca32984237a8a011b5bf367e53341a265b2a4 (diff) | |
| download | lwn-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.c | 6 |
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); |