Re: [Xenomai-core] [PATCH] Fixs doxygen doc on rt_queue_read in ksrc/native/queue.c (for SVN version)
[a few interruptions later]
Jan Kiszka wrote:
Rodrigo Rosenfeld Rosas wrote:
BTW, please, could someone confirm the rt_task_delete(NULL) bug in SVN?
Half-confirmed, there is something fishy. I'm struggling with the
debugger ATM, not sure yet who's wrong ;). It tells me rt_task_delete of
the skin module is entered with task != NULL...
...which turns out to be fine, just appears redundant to me when
comparing __rt_task_delete and rt_task_delete for the task=NULL case.
Anyway, leaving a native task with rt_task_delete(NULL) raises SIGKILL
to the whole process instead of just the task (pthread). This lets your
program terminate unexpectedly - I would say: a bug. And this doesn't
happen with 2.1?
I guess the easiest way to solve this is to catch NULL in userspace and
call pthread_exit() in favour of the skin service (the POSIX skin uses
pthread_exit anyway), see attached patch. Someone just has to confirm
that there will be no problem hidden by this approach.
Jan
PS: What's the reason for if (err == -ESRCH) return 0 in
src/skins/native/task.c, rt_task_delete? Why is that error generate in
the first place if it is zeroed out here?
Index: src/skins/native/task.c
===
--- src/skins/native/task.c (revision 923)
+++ src/skins/native/task.c (working copy)
@@ -212,7 +212,10 @@ int rt_task_delete (RT_TASK *task)
{
int err;
-if (task task-opaque2) {
+if (!task)
+ pthread_exit(NULL);
+
+if (task-opaque2) {
err = pthread_cancel((pthread_t)task-opaque2);
if (err)
return -err;
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Re: [Xenomai-core] [PATCH] Fixs doxygen doc on rt_queue_read in ksrc/native/queue.c (for SVN version)
Jan Kiszka wrote:
[a few interruptions later]
Jan Kiszka wrote:
Rodrigo Rosenfeld Rosas wrote:
BTW, please, could someone confirm the rt_task_delete(NULL) bug in SVN?
Half-confirmed, there is something fishy. I'm struggling with the
debugger ATM, not sure yet who's wrong ;). It tells me rt_task_delete of
the skin module is entered with task != NULL...
...which turns out to be fine, just appears redundant to me when
comparing __rt_task_delete and rt_task_delete for the task=NULL case.
Anyway, leaving a native task with rt_task_delete(NULL) raises SIGKILL
to the whole process instead of just the task (pthread). This lets your
program terminate unexpectedly - I would say: a bug. And this doesn't
happen with 2.1?
It's a side-effect of a recent bug fix in ksrc/nucleus/shadow.c; now
killing a thread raises a group signal wiping out the entire process.
Ok, it's a bit drastic, will fix.
I guess the easiest way to solve this is to catch NULL in userspace and
call pthread_exit() in favour of the skin service (the POSIX skin uses
pthread_exit anyway), see attached patch. Someone just has to confirm
that there will be no problem hidden by this approach.
Passing NULL needs to work including from user-space; the kernel-space
is ok with this, and the API must behave the same way regardless of the
execution space. Should fix as needed.
Jan
PS: What's the reason for if (err == -ESRCH) return 0 in
src/skins/native/task.c, rt_task_delete? Why is that error generate in
the first place if it is zeroed out here?
Index: src/skins/native/task.c
===
--- src/skins/native/task.c (revision 923)
+++ src/skins/native/task.c (working copy)
@@ -212,7 +212,10 @@ int rt_task_delete (RT_TASK *task)
{
int err;
-if (task task-opaque2) {
+if (!task)
+ pthread_exit(NULL);
+
+if (task-opaque2) {
err = pthread_cancel((pthread_t)task-opaque2);
if (err)
return -err;
--
Philippe.
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Re: [Xenomai-core] [PATCH] Fixs doxygen doc on rt_queue_read in ksrc/native/queue.c (for SVN version)
Philippe Gerum wrote: Philippe Gerum wrote: Jan Kiszka wrote: [a few interruptions later] Jan Kiszka wrote: Rodrigo Rosenfeld Rosas wrote: BTW, please, could someone confirm the rt_task_delete(NULL) bug in SVN? Half-confirmed, there is something fishy. I'm struggling with the debugger ATM, not sure yet who's wrong ;). It tells me rt_task_delete of the skin module is entered with task != NULL... ...which turns out to be fine, just appears redundant to me when comparing __rt_task_delete and rt_task_delete for the task=NULL case. Anyway, leaving a native task with rt_task_delete(NULL) raises SIGKILL to the whole process instead of just the task (pthread). This lets your program terminate unexpectedly - I would say: a bug. And this doesn't happen with 2.1? It's a side-effect of a recent bug fix in ksrc/nucleus/shadow.c; now killing Er, deleting is the right word here. Sending a thread a termination signal must kill the entire process as per POSIX, and will continue to do so. Calling rt_task_delete() to explicitely delete a single thread from within the containing process is another story. The current issue is due to the fact that no distinction is made on the caller: rt_task_delete() targeting a thread from another process should wipe out the entire target process; otherwise, only the local target thread should be deleted. It's not clear whether we should still wipe out the entire process when the target thread is not the current one, regardless of the fact such thread is a member of the same process or not. I'm open to suggestions. Killing other threads within the same process currently only works due to pthread_cancel. I don't see a portable equivalent for foreign processes yet as well. :-/ I guess the thread termination signal sent by pthread_cancel depends on glibc internals, specifically its variant (NTPL or linux-threads), doesn't it? Didn't we already have this discussion?? For now I would say the best we can do is to avoid the rt_task_delete(NULL) side effect in userspace (as I suggested) and live with the limitation of terminating the whole process when using the (rather unusual) cross-process rt_task_delete. a thread raises a group signal wiping out the entire process. Ok, it's a bit drastic, will fix. I guess the easiest way to solve this is to catch NULL in userspace and call pthread_exit() in favour of the skin service (the POSIX skin uses pthread_exit anyway), see attached patch. Someone just has to confirm that there will be no problem hidden by this approach. Passing NULL needs to work including from user-space; the kernel-space is ok with this, and the API must behave the same way regardless of the execution space. Should fix as needed. Jan PS: What's the reason for if (err == -ESRCH) return 0 in src/skins/native/task.c, rt_task_delete? Why is that error generate in the first place if it is zeroed out here? attention: unanswered question above ;) Jan signature.asc Description: OpenPGP digital signature ___ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
[Xenomai-core] [PATCH] Fixs doxygen doc on rt_queue_read in ksrc/native/queue.c (for SVN version)
BTW, please, could someone confirm the rt_task_delete(NULL) bug in SVN? Regards, Rodrigo. Index: ksrc/skins/native/queue.c === --- ksrc/skins/native/queue.c (revisão 923) +++ ksrc/skins/native/queue.c (cópia de trabalho) @@ -885,7 +885,7 @@ } /** - * @fn ssize_t rt_queue_read(RT_QUEUE *q,void *buf,RTIME timeout) + * @fn ssize_t rt_queue_read(RT_QUEUE *q,void *buf,size_t size,RTIME timeout) * * @brief Read a message from a queue. * ___ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
