On 02.08.21 18:56, Jan Kiszka via Xenomai wrote:
> From: Jan Kiszka <jan.kis...@siemens.com>
>
> Make sure that we consider all pids taken from or sent to userspace via
> syscalls as virtual. That means converting them to global pids before
> processing them or converting them back to virtual pids in the caller's
> namespace before reporting them. We also need to switch thread hashing
> from vpids to real pids.
>
> Not converted is the procfs interface as this one continues to provide
> only a global view on cobalt objects and associated pids.
>
> A few syscall tracepoints that report the vpid as passed down from
> userspace get adjusted in their output so that it is clear that no
> global pid is shown.
>
> Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
> ---
>
> Changes in v3:
> - handle process-local thread lookups correctly (hopefully)
>
> This is in next for a while and ran several test cycles. Even if we
> should have remaining issues under pid namespaces, we should not have
> regressions in the normal cases.
>
> include/cobalt/kernel/thread.h | 2 ++
> kernel/cobalt/posix/event.c | 2 +-
> kernel/cobalt/posix/mqueue.c | 2 +-
> kernel/cobalt/posix/process.c | 14 ++++++++++++++
> kernel/cobalt/posix/process.h | 2 ++
> kernel/cobalt/posix/sched.c | 10 ++++++----
> kernel/cobalt/posix/sem.c | 2 +-
> kernel/cobalt/posix/signal.c | 10 ++++++----
> kernel/cobalt/posix/thread.c | 18 ++++++++++--------
> kernel/cobalt/posix/thread.h | 2 +-
> kernel/cobalt/thread.c | 10 ++++++++++
> kernel/cobalt/trace/cobalt-posix.h | 4 ++--
> 12 files changed, 56 insertions(+), 22 deletions(-)
>
> diff --git a/include/cobalt/kernel/thread.h b/include/cobalt/kernel/thread.h
> index b79cb84296..4c8a0b9f2a 100644
> --- a/include/cobalt/kernel/thread.h
> +++ b/include/cobalt/kernel/thread.h
> @@ -450,6 +450,8 @@ char *xnthread_format_status(unsigned long status,
>
> pid_t xnthread_host_pid(struct xnthread *thread);
>
> +pid_t xnthread_host_vpid(struct xnthread *thread);
> +
> int xnthread_set_clock(struct xnthread *thread,
> struct xnclock *newclock);
>
> diff --git a/kernel/cobalt/posix/event.c b/kernel/cobalt/posix/event.c
> index 3712154f53..5871106301 100644
> --- a/kernel/cobalt/posix/event.c
> +++ b/kernel/cobalt/posix/event.c
> @@ -352,7 +352,7 @@ COBALT_SYSCALL(event_inquire, current,
> xnsynch_for_each_sleeper(thread, &event->synch) {
> if (nrwait >= nrpids)
> break;
> - t[nrwait++] = xnthread_host_pid(thread);
> + t[nrwait++] = xnthread_host_vpid(thread);
> }
> }
>
> diff --git a/kernel/cobalt/posix/mqueue.c b/kernel/cobalt/posix/mqueue.c
> index dd8acd55b0..fcde87a077 100644
> --- a/kernel/cobalt/posix/mqueue.c
> +++ b/kernel/cobalt/posix/mqueue.c
> @@ -720,7 +720,7 @@ mq_notify(struct cobalt_mqd *mqd, unsigned index, const
> struct sigevent *evp)
> * receiver's namespaces. We pass the receiver's creds
> * into the init namespace instead.
> */
> - mq->si.si_pid = task_pid_nr(current);
> + mq->si.si_pid = task_pid_vnr(current);
> mq->si.si_uid = get_current_uuid();
> }
>
> diff --git a/kernel/cobalt/posix/process.c b/kernel/cobalt/posix/process.c
> index 1f059ad830..98b7df33fb 100644
> --- a/kernel/cobalt/posix/process.c
> +++ b/kernel/cobalt/posix/process.c
> @@ -975,6 +975,20 @@ int cobalt_handle_cleanup_event(struct mm_struct *mm)
> return KEVENT_PROPAGATE;
> }
>
> +pid_t cobalt_vpid2pid_nr(pid_t vpid)
> +{
> + struct pid *pid;
> + pid_t nr = -1;
> +
> + rcu_read_lock();
This is not a good idea, at least for I-pipe which is not RCU-compatible
(Dovetail just gained that).
I think we need to rest this approach for now, either under I-pipe
gained support for RCU read-side access or we switched to Dovetail
completely. Pulling it from next.
Jan
> + pid = find_vpid(vpid);
> + if (pid)
> + nr = pid_nr(pid);
> + rcu_read_unlock();
> +
> + return nr;
> +}
> +
> static int attach_process(struct cobalt_process *process)
> {
> struct cobalt_ppd *p = &process->sys_ppd;
> diff --git a/kernel/cobalt/posix/process.h b/kernel/cobalt/posix/process.h
> index 279707a680..46dff43b7a 100644
> --- a/kernel/cobalt/posix/process.h
> +++ b/kernel/cobalt/posix/process.h
> @@ -175,4 +175,6 @@ int cobalt_handle_cleanup_event(struct mm_struct *mm);
>
> int cobalt_handle_user_return(struct task_struct *task);
>
> +pid_t cobalt_vpid2pid_nr(pid_t vpid);
> +
> #endif /* !_COBALT_POSIX_PROCESS_H */
> diff --git a/kernel/cobalt/posix/sched.c b/kernel/cobalt/posix/sched.c
> index 4fd9c2b46e..26259fbd3f 100644
> --- a/kernel/cobalt/posix/sched.c
> +++ b/kernel/cobalt/posix/sched.c
> @@ -736,7 +736,7 @@ COBALT_SYSCALL(sched_weightprio, current,
> return __cobalt_sched_weightprio(policy, ¶m_ex);
> }
>
> -int cobalt_sched_setscheduler_ex(pid_t pid,
> +int cobalt_sched_setscheduler_ex(pid_t vpid,
> int policy,
> const struct sched_param_ex *param_ex,
> __u32 __user *u_winoff,
> @@ -747,9 +747,11 @@ int cobalt_sched_setscheduler_ex(pid_t pid,
> int ret, promoted = 0;
> spl_t s;
>
> - trace_cobalt_sched_setscheduler(pid, policy, param_ex);
> + trace_cobalt_sched_setscheduler(vpid, policy, param_ex);
> +
> + if (vpid) {
> + pid_t pid = cobalt_vpid2pid_nr(vpid);
>
> - if (pid) {
> xnlock_get_irqsave(&nklock, s);
> thread = cobalt_thread_find(pid);
> xnlock_put_irqrestore(&nklock, s);
> @@ -757,7 +759,7 @@ int cobalt_sched_setscheduler_ex(pid_t pid,
> thread = cobalt_current_thread();
>
> if (thread == NULL) {
> - if (u_winoff == NULL || pid != task_pid_vnr(current))
> + if (u_winoff == NULL || vpid != task_pid_vnr(current))
> return -ESRCH;
>
> thread = cobalt_thread_shadow(&hkey, u_winoff);
> diff --git a/kernel/cobalt/posix/sem.c b/kernel/cobalt/posix/sem.c
> index 72b20c78d2..030ce8ffed 100644
> --- a/kernel/cobalt/posix/sem.c
> +++ b/kernel/cobalt/posix/sem.c
> @@ -602,7 +602,7 @@ COBALT_SYSCALL(sem_inquire, current,
> xnsynch_for_each_sleeper(thread, &sem->synchbase) {
> if (nrwait >= nrpids)
> break;
> - t[nrwait++] = xnthread_host_pid(thread);
> + t[nrwait++] = xnthread_host_vpid(thread);
> }
> }
>
> diff --git a/kernel/cobalt/posix/signal.c b/kernel/cobalt/posix/signal.c
> index 0b43b5fcfa..c2c9c092c4 100644
> --- a/kernel/cobalt/posix/signal.c
> +++ b/kernel/cobalt/posix/signal.c
> @@ -510,7 +510,7 @@ int __cobalt_kill(struct cobalt_thread *thread, int sig,
> int group) /* nklocked,
> sigp->si.si_signo = sig;
> sigp->si.si_errno = 0;
> sigp->si.si_code = SI_USER;
> - sigp->si.si_pid = task_pid_nr(current);
> + sigp->si.si_pid = task_pid_vnr(current);
> sigp->si.si_uid = get_current_uuid();
> if (cobalt_signal_send(thread, sigp, group) <= 0)
> cobalt_signal_free(sigp);
> @@ -525,8 +525,9 @@ int __cobalt_kill(struct cobalt_thread *thread, int sig,
> int group) /* nklocked,
> return ret;
> }
>
> -COBALT_SYSCALL(kill, conforming, (pid_t pid, int sig))
> +COBALT_SYSCALL(kill, conforming, (pid_t vpid, int sig))
> {
> + pid_t pid = cobalt_vpid2pid_nr(vpid);
> struct cobalt_thread *thread;
> int ret;
> spl_t s;
> @@ -544,8 +545,9 @@ COBALT_SYSCALL(kill, conforming, (pid_t pid, int sig))
> return ret;
> }
>
> -int __cobalt_sigqueue(pid_t pid, int sig, const union sigval *value)
> +int __cobalt_sigqueue(pid_t vpid, int sig, const union sigval *value)
> {
> + pid_t pid = cobalt_vpid2pid_nr(vpid);
> struct cobalt_sigpending *sigp;
> struct cobalt_thread *thread;
> int ret = 0;
> @@ -569,7 +571,7 @@ int __cobalt_sigqueue(pid_t pid, int sig, const union
> sigval *value)
> sigp->si.si_signo = sig;
> sigp->si.si_errno = 0;
> sigp->si.si_code = SI_QUEUE;
> - sigp->si.si_pid = task_pid_nr(current);
> + sigp->si.si_pid = task_pid_vnr(current);
> sigp->si.si_uid = get_current_uuid();
> sigp->si.si_value = *value;
> if (cobalt_signal_send(thread, sigp, 1) <= 0)
> diff --git a/kernel/cobalt/posix/thread.c b/kernel/cobalt/posix/thread.c
> index cdeb66d4f3..6a79fecb5c 100644
> --- a/kernel/cobalt/posix/thread.c
> +++ b/kernel/cobalt/posix/thread.c
> @@ -176,11 +176,11 @@ struct cobalt_thread *cobalt_thread_find(pid_t pid) /*
> nklocked, IRQs off */
> }
> EXPORT_SYMBOL_GPL(cobalt_thread_find);
>
> -struct cobalt_thread *cobalt_thread_find_local(pid_t pid) /* nklocked, IRQs
> off */
> +struct cobalt_thread *cobalt_thread_find_local(pid_t vpid) /* nklocked, IRQs
> off */
> {
> struct cobalt_thread *thread;
>
> - thread = cobalt_thread_find(pid);
> + thread = cobalt_thread_find(cobalt_vpid2pid_nr(vpid));
> if (thread == NULL || thread->hkey.mm != current->mm)
> return NULL;
>
> @@ -624,7 +624,7 @@ int __cobalt_thread_create(unsigned long pth, int policy,
> return ret;
> }
>
> - if (!thread_hash(&hkey, thread, task_pid_vnr(p))) {
> + if (!thread_hash(&hkey, thread, task_pid_nr(p))) {
> ret = -EAGAIN;
> goto fail;
> }
> @@ -682,7 +682,7 @@ cobalt_thread_shadow(struct cobalt_local_hkey *hkey,
> return ERR_PTR(ret);
> }
>
> - if (!thread_hash(hkey, thread, task_pid_vnr(current))) {
> + if (!thread_hash(hkey, thread, task_pid_nr(current))) {
> ret = -EAGAIN;
> goto fail;
> }
> @@ -819,7 +819,7 @@ COBALT_SYSCALL(thread_getpid, current, (unsigned long
> pth))
> if (thread == NULL)
> pid = -ESRCH;
> else
> - pid = xnthread_host_pid(&thread->threadbase);
> + pid = xnthread_host_vpid(&thread->threadbase);
>
> xnlock_put_irqrestore(&nklock, s);
>
> @@ -827,7 +827,7 @@ COBALT_SYSCALL(thread_getpid, current, (unsigned long
> pth))
> }
>
> COBALT_SYSCALL(thread_getstat, current,
> - (pid_t pid, struct cobalt_threadstat __user *u_stat))
> + (pid_t vpid, struct cobalt_threadstat __user *u_stat))
> {
> struct cobalt_threadstat stat;
> struct cobalt_thread *p;
> @@ -835,14 +835,16 @@ COBALT_SYSCALL(thread_getstat, current,
> xnticks_t xtime;
> spl_t s;
>
> - trace_cobalt_pthread_stat(pid);
> + trace_cobalt_pthread_stat(vpid);
>
> - if (pid == 0) {
> + if (vpid == 0) {
> thread = xnthread_current();
> if (thread == NULL)
> return -EPERM;
> xnlock_get_irqsave(&nklock, s);
> } else {
> + pid_t pid = cobalt_vpid2pid_nr(vpid);
> +
> xnlock_get_irqsave(&nklock, s);
> p = cobalt_thread_find(pid);
> if (p == NULL) {
> diff --git a/kernel/cobalt/posix/thread.h b/kernel/cobalt/posix/thread.h
> index 51be372a7a..66e3a88223 100644
> --- a/kernel/cobalt/posix/thread.h
> +++ b/kernel/cobalt/posix/thread.h
> @@ -146,7 +146,7 @@ int cobalt_thread_setschedprio(unsigned long pth,
>
> struct cobalt_thread *cobalt_thread_find(pid_t pid);
>
> -struct cobalt_thread *cobalt_thread_find_local(pid_t pid);
> +struct cobalt_thread *cobalt_thread_find_local(pid_t vpid);
>
> struct cobalt_thread *cobalt_thread_lookup(unsigned long pth);
>
> diff --git a/kernel/cobalt/thread.c b/kernel/cobalt/thread.c
> index 2c1ec6d3a4..9a97213fbe 100644
> --- a/kernel/cobalt/thread.c
> +++ b/kernel/cobalt/thread.c
> @@ -388,6 +388,16 @@ pid_t xnthread_host_pid(struct xnthread *thread)
> return task_pid_nr(xnthread_host_task(thread));
> }
>
> +pid_t xnthread_host_vpid(struct xnthread *thread)
> +{
> + if (xnthread_test_state(thread, XNROOT))
> + return 0;
> + if (!xnthread_host_task(thread))
> + return -1;
> +
> + return task_pid_vnr(xnthread_host_task(thread));
> +}
> +
> int xnthread_set_clock(struct xnthread *thread, struct xnclock *newclock)
> {
> spl_t s;
> diff --git a/kernel/cobalt/trace/cobalt-posix.h
> b/kernel/cobalt/trace/cobalt-posix.h
> index 3df9295541..d994007bba 100644
> --- a/kernel/cobalt/trace/cobalt-posix.h
> +++ b/kernel/cobalt/trace/cobalt-posix.h
> @@ -252,7 +252,7 @@ DECLARE_EVENT_CLASS(cobalt_posix_scheduler,
> memcpy(__get_dynamic_array(param_ex), param_ex,
> sizeof(*param_ex));
> ),
>
> - TP_printk("pid=%d policy=%s param={ %s }",
> + TP_printk("vpid=%d policy=%s param={ %s }",
> __entry->pid,
> cobalt_print_sched_policy(__entry->policy),
> __parse_sched_params(__entry->policy,
> @@ -369,7 +369,7 @@ DECLARE_EVENT_CLASS(cobalt_posix_pid,
> TP_fast_assign(
> __entry->pid = pid;
> ),
> - TP_printk("pid=%d", __entry->pid)
> + TP_printk("vpid=%d", __entry->pid)
> );
>
> DEFINE_EVENT(cobalt_posix_pid, cobalt_pthread_stat,
>
--
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