[LTP] [PATCH v2] openposix: timer_*/speculative: Skip untestable optional behavior on Linux

[LTP] [PATCH v2] openposix: timer_*/speculative: Skip untestable optional behavior on Linux

[Avinesh Kumar via ltp]

From: Avinesh Kumar <avinesh.kumar@suse.com>

timer_delete/speculative/5-{1,2}, timer_getoverrun/speculative/6-{1,2,3},
timer_gettime/speculative/6-{1,2,3}, and timer_settime/speculative/12-{1,2,3}
all test EINVAL for an invalid timerid, which POSIX Issue 6/TC2 made
optional rather than required.[0][1]
Linux does not implement this optional behavior, so skip it there with
PTS_UNSUPPORTED and leave the test intact for implementations that do.

[0] https://pubs.opengroup.org/onlinepubs/9799919799/functions/timer_getoverrun.html
[1] https://pubs.opengroup.org/onlinepubs/9799919799/functions/timer_delete.html

Suggested-by: Cyril Hrubis <chrubis@suse.cz>
Signed-off-by: Avinesh Kumar <avinesh.kumar@suse.com>
---
 .../conformance/interfaces/timer_delete/speculative/5-1.c    | 5 +++++
 .../conformance/interfaces/timer_delete/speculative/5-2.c    | 5 +++++
 .../interfaces/timer_getoverrun/speculative/6-1.c            | 5 +++++
 .../interfaces/timer_getoverrun/speculative/6-2.c            | 5 +++++
 .../interfaces/timer_getoverrun/speculative/6-3.c            | 5 +++++
 .../conformance/interfaces/timer_gettime/speculative/6-1.c   | 5 +++++
 .../conformance/interfaces/timer_gettime/speculative/6-2.c   | 5 +++++
 .../conformance/interfaces/timer_gettime/speculative/6-3.c   | 5 +++++
 .../conformance/interfaces/timer_settime/speculative/12-1.c  | 5 +++++
 .../conformance/interfaces/timer_settime/speculative/12-2.c  | 5 +++++
 .../conformance/interfaces/timer_settime/speculative/12-3.c  | 5 +++++
 11 files changed, 55 insertions(+)

diff --git a/testcases/open_posix_testsuite/conformance/interfaces/timer_delete/speculative/5-1.c b/testcases/open_posix_testsuite/conformance/interfaces/timer_delete/speculative/5-1.c
index 912cf5800e6f..7c776236d31d 100644
--- a/testcases/open_posix_testsuite/conformance/interfaces/timer_delete/speculative/5-1.c
+++ b/testcases/open_posix_testsuite/conformance/interfaces/timer_delete/speculative/5-1.c
@@ -19,6 +19,10 @@
 
 int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 {
+#ifdef __linux__
+	printf("Linux does not implement this optional behavior\n");
+	return PTS_UNSUPPORTED;
+#else
 	timer_t tid;
 	int tval = BOGUSTIMERID;
 	tid = (timer_t) & tval;
@@ -37,4 +41,5 @@ int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 
 	printf("timer_delete() did not return -1\n");
 	return PTS_PASS;
+#endif
 }
diff --git a/testcases/open_posix_testsuite/conformance/interfaces/timer_delete/speculative/5-2.c b/testcases/open_posix_testsuite/conformance/interfaces/timer_delete/speculative/5-2.c
index 74eeb46793b2..63574bfd58f7 100644
--- a/testcases/open_posix_testsuite/conformance/interfaces/timer_delete/speculative/5-2.c
+++ b/testcases/open_posix_testsuite/conformance/interfaces/timer_delete/speculative/5-2.c
@@ -34,6 +34,10 @@ static void handler(int signo PTS_ATTRIBUTE_UNUSED)
 
 int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 {
+#ifdef __linux__
+	printf("Linux does not implement this optional behavior\n");
+	return PTS_UNSUPPORTED;
+#else
 	struct sigevent ev;
 	struct sigaction act;
 	timer_t tid;
@@ -91,4 +95,5 @@ int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 
 	printf("fcn did not return -1\n");
 	return PTS_PASS;
+#endif
 }
diff --git a/testcases/open_posix_testsuite/conformance/interfaces/timer_getoverrun/speculative/6-1.c b/testcases/open_posix_testsuite/conformance/interfaces/timer_getoverrun/speculative/6-1.c
index 6e18560e5084..31c8a4df3d17 100644
--- a/testcases/open_posix_testsuite/conformance/interfaces/timer_getoverrun/speculative/6-1.c
+++ b/testcases/open_posix_testsuite/conformance/interfaces/timer_getoverrun/speculative/6-1.c
@@ -19,6 +19,10 @@
 
 int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 {
+#ifdef __linux__
+	printf("Linux does not implement this optional behavior\n");
+	return PTS_UNSUPPORTED;
+#else
 	timer_t tid;
 	int tval = BOGUSTID;
 	tid = (timer_t) & tval;
@@ -36,4 +40,5 @@ int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 
 	printf("fcn did not return -1\n");
 	return PTS_PASS;
+#endif
 }
diff --git a/testcases/open_posix_testsuite/conformance/interfaces/timer_getoverrun/speculative/6-2.c b/testcases/open_posix_testsuite/conformance/interfaces/timer_getoverrun/speculative/6-2.c
index 2d7f3967ced1..3004b1eb80ba 100644
--- a/testcases/open_posix_testsuite/conformance/interfaces/timer_getoverrun/speculative/6-2.c
+++ b/testcases/open_posix_testsuite/conformance/interfaces/timer_getoverrun/speculative/6-2.c
@@ -26,6 +26,10 @@
 
 int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 {
+#ifdef __linux__
+	printf("Linux does not implement this optional behavior\n");
+	return PTS_UNSUPPORTED;
+#else
 	struct sigevent ev;
 	timer_t tid;
 
@@ -55,4 +59,5 @@ int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 
 	printf("fcn did not return -1\n");
 	return PTS_PASS;
+#endif
 }
diff --git a/testcases/open_posix_testsuite/conformance/interfaces/timer_getoverrun/speculative/6-3.c b/testcases/open_posix_testsuite/conformance/interfaces/timer_getoverrun/speculative/6-3.c
index 933a31dcd3e7..bd443e7629aa 100644
--- a/testcases/open_posix_testsuite/conformance/interfaces/timer_getoverrun/speculative/6-3.c
+++ b/testcases/open_posix_testsuite/conformance/interfaces/timer_getoverrun/speculative/6-3.c
@@ -23,6 +23,10 @@
 
 int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 {
+#ifdef __linux__
+	printf("Linux does not implement this optional behavior\n");
+	return PTS_UNSUPPORTED;
+#else
 	struct sigevent ev;
 	timer_t tid;
 
@@ -47,4 +51,5 @@ int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 
 	printf("fcn did not return -1\n");
 	return PTS_PASS;
+#endif
 }
diff --git a/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-1.c b/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-1.c
index d09c2f70901d..82a2f0b508dd 100644
--- a/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-1.c
+++ b/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-1.c
@@ -19,6 +19,10 @@
 
 int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 {
+#ifdef __linux__
+	printf("Linux does not implement this optional behavior\n");
+	return PTS_UNSUPPORTED;
+#else
 	timer_t tid;
 	struct itimerspec its;
 	int tval = BOGUSTID;
@@ -35,4 +39,5 @@ int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 	}
 	printf("fcn did not return -1\n");
 	return PTS_PASS;
+#endif
 }
diff --git a/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-2.c b/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-2.c
index 88a8d221914b..df103dd78b9d 100644
--- a/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-2.c
+++ b/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-2.c
@@ -21,6 +21,10 @@
 
 int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 {
+#ifdef __linux__
+	printf("Linux does not implement this optional behavior\n");
+	return PTS_UNSUPPORTED;
+#else
 	struct sigevent ev;
 	timer_t tid;
 	struct itimerspec its;
@@ -45,4 +49,5 @@ int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 	}
 	printf("fcn did not return -1\n");
 	return PTS_PASS;
+#endif
 }
diff --git a/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-3.c b/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-3.c
index ef7c37f5eb99..4b901e0d4329 100644
--- a/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-3.c
+++ b/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-3.c
@@ -21,6 +21,10 @@
 
 int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 {
+#ifdef __linux__
+	printf("Linux does not implement this optional behavior\n");
+	return PTS_UNSUPPORTED;
+#else
 	struct sigevent ev;
 	timer_t tid;
 	struct itimerspec its;
@@ -49,4 +53,5 @@ int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 	}
 	printf("fcn did not return -1\n");
 	return PTS_PASS;
+#endif
 }
diff --git a/testcases/open_posix_testsuite/conformance/interfaces/timer_settime/speculative/12-1.c b/testcases/open_posix_testsuite/conformance/interfaces/timer_settime/speculative/12-1.c
index 5d4e1dda30ba..e20766ba5838 100644
--- a/testcases/open_posix_testsuite/conformance/interfaces/timer_settime/speculative/12-1.c
+++ b/testcases/open_posix_testsuite/conformance/interfaces/timer_settime/speculative/12-1.c
@@ -18,6 +18,10 @@
 
 int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 {
+#ifdef __linux__
+	printf("Linux does not implement this optional behavior\n");
+	return PTS_UNSUPPORTED;
+#else
 	timer_t tid;
 	struct itimerspec its;
 	int tval = BOGUSTID;
@@ -39,4 +43,5 @@ int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 	}
 	printf("fcn did not return -1\n");
 	return PTS_PASS;
+#endif
 }
diff --git a/testcases/open_posix_testsuite/conformance/interfaces/timer_settime/speculative/12-2.c b/testcases/open_posix_testsuite/conformance/interfaces/timer_settime/speculative/12-2.c
index 3b6901c25dc7..83c7aa10c7ce 100644
--- a/testcases/open_posix_testsuite/conformance/interfaces/timer_settime/speculative/12-2.c
+++ b/testcases/open_posix_testsuite/conformance/interfaces/timer_settime/speculative/12-2.c
@@ -25,6 +25,10 @@
 
 int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 {
+#ifdef __linux__
+	printf("Linux does not implement this optional behavior\n");
+	return PTS_UNSUPPORTED;
+#else
 	struct sigevent ev;
 	timer_t tid;
 	struct itimerspec its;
@@ -54,4 +58,5 @@ int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 	}
 	printf("fcn did not return -1\n");
 	return PTS_PASS;
+#endif
 }
diff --git a/testcases/open_posix_testsuite/conformance/interfaces/timer_settime/speculative/12-3.c b/testcases/open_posix_testsuite/conformance/interfaces/timer_settime/speculative/12-3.c
index 04ceb2745af3..c4c469410874 100644
--- a/testcases/open_posix_testsuite/conformance/interfaces/timer_settime/speculative/12-3.c
+++ b/testcases/open_posix_testsuite/conformance/interfaces/timer_settime/speculative/12-3.c
@@ -23,6 +23,10 @@
 
 int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 {
+#ifdef __linux__
+	printf("Linux does not implement this optional behavior\n");
+	return PTS_UNSUPPORTED;
+#else
 	struct sigevent ev;
 	timer_t tid;
 	struct itimerspec its;
@@ -56,4 +60,5 @@ int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 	}
 	printf("fcn did not return -1\n");
 	return PTS_PASS;
+#endif
 }
-- 
2.55.0


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Re: [LTP] openposix: timer_*/speculative: Skip untestable optional behavior on Linux

[linuxtestproject.agent]

Hi Avinesh,

On Wed, 19 Aug 2026, Avinesh Kumar wrote:
> openposix: timer_*/speculative: Skip untestable optional behavior on Linux

> +#ifdef __linux__
> +	printf("Linux does not implement this optional behavior\n");
> +	return PTS_UNSUPPORTED;
> +#else

Could these branches be removed from all eleven tests? Linux 7.2 uses
scoped_timer_get_or_fail() to return -EINVAL for invalid timer IDs in
timer_gettime(), timer_getoverrun(), timer_settime(), and timer_delete().
The installed man pages document the same EINVAL result.

More directly, every pre-patch test reports errno == EINVAL and returns
PTS_PASS when built and run on Linux. The platform check therefore replaces
working coverage with PTS_UNSUPPORTED, and the quoted runtime message is not
accurate.

Verdict - Needs revision

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findings are genuine. If you find issues with the review, please
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Regards,
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Re: [LTP] openposix: timer_*/speculative: Skip untestable optional behavior on Linux

[Andrea Cervesato via ltp]

Hi Avinesh,

> > +#ifdef __linux__
> > +	printf("Linux does not implement this optional behavior\n");
> > +	return PTS_UNSUPPORTED;
> > +#else
> 
> Could these branches be removed from all eleven tests? Linux 7.2 uses
> scoped_timer_get_or_fail() to return -EINVAL for invalid timer IDs in
> timer_gettime(), timer_getoverrun(), timer_settime(), and timer_delete().
> The installed man pages document the same EINVAL result.

can you please take a look at this?

--
Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com

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Re: [LTP] openposix: timer_*/speculative: Skip untestable optional behavior on Linux

[Cyril Hrubis]

Hi!
> > openposix: timer_*/speculative: Skip untestable optional behavior on Linux
> 
> > +#ifdef __linux__
> > +	printf("Linux does not implement this optional behavior\n");
> > +	return PTS_UNSUPPORTED;
> > +#else
> 
> Could these branches be removed from all eleven tests? Linux 7.2 uses
> scoped_timer_get_or_fail() to return -EINVAL for invalid timer IDs in
> timer_gettime(), timer_getoverrun(), timer_settime(), and timer_delete().
> The installed man pages document the same EINVAL result.
> 
> More directly, every pre-patch test reports errno == EINVAL and returns
> PTS_PASS when built and run on Linux. The platform check therefore replaces
> working coverage with PTS_UNSUPPORTED, and the quoted runtime message is not
> accurate.

That's the kernel part, apparently it's more complex in libc.

Libc has two types of timer_t values, either it's a directly kernel
timer id (small int) or a pointer to a structure that holds the id.

The timer libc functions, before calling the kernel syscall, convert the
libc timer id into kernel timer id with:

static inline kernel_timer_t
timerid_to_kernel_timer (timer_t timerid)
{
  if (timer_is_sigev_thread (timerid))
    return timerid_to_timer (timerid)->ktimerid;
  else
    return (kernel_timer_t) ((uintptr_t) timerid);
}

The library does a bit of magic with the pointers:

https://codebrowser.dev/glibc/glibc/sysdeps/unix/sysv/linux/kernel-posix-timers.h.html

But overall it checks the MSB bit of the pointer to figure out if it's
kernel timer id which should be passed verbatim, or a structure that
needs to be dereferenced.

Looking at the timer_gettime/speculative/6-1.c we do pass a pointer to
the stack (instead of the invalid value) which on 32bit may be an
address with the MSB bit set. So this triggers undefined behavior, since
glibc thinks it's a pointer to it's internal data structure, but the
real pointer the glibc exports as the timer is bit-shifted. Hence we
access random and possibly invalid address. With some luck that address
is accesible and contains non-zero data and we end up passing invalid
timer ID to the kernel, but when I straced the test, the value was
pretty much random.

With that in mind, we can fix the test with passing the BOGUSID instead
of random stack pointer:

diff --git a/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-1.c b/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-1.c
index d09c2f709..c35dd816f 100644
--- a/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-1.c
+++ b/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-1.c
@@ -21,8 +21,7 @@ int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
 {
        timer_t tid;
        struct itimerspec its;
-       int tval = BOGUSTID;
-       tid = (timer_t) & tval;
+       tid = (timer_t) BOGUSTID;
        if (timer_gettime(tid, &its) == -1) {
                if (EINVAL == errno) {
                        printf("fcn returned -1 and errno==EINVAL\n");


-- 
Cyril Hrubis
chrubis@suse.cz

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Re: [LTP] openposix: timer_*/speculative: Skip untestable optional behavior on Linux

[Avinesh Kumar via ltp]

Hi Cyril,

On 8/31/26 12:15 PM, Cyril Hrubis wrote:
> Hi!
>>> openposix: timer_*/speculative: Skip untestable optional behavior on Linux
>>
>>> +#ifdef __linux__
>>> +	printf("Linux does not implement this optional behavior\n");
>>> +	return PTS_UNSUPPORTED;
>>> +#else
>>
>> Could these branches be removed from all eleven tests? Linux 7.2 uses
>> scoped_timer_get_or_fail() to return -EINVAL for invalid timer IDs in
>> timer_gettime(), timer_getoverrun(), timer_settime(), and timer_delete().
>> The installed man pages document the same EINVAL result.
>>
>> More directly, every pre-patch test reports errno == EINVAL and returns
>> PTS_PASS when built and run on Linux. The platform check therefore replaces
>> working coverage with PTS_UNSUPPORTED, and the quoted runtime message is not
>> accurate.
> 
> That's the kernel part, apparently it's more complex in libc.
> 
> Libc has two types of timer_t values, either it's a directly kernel
> timer id (small int) or a pointer to a structure that holds the id.
> 
> The timer libc functions, before calling the kernel syscall, convert the
> libc timer id into kernel timer id with:
> 
> static inline kernel_timer_t
> timerid_to_kernel_timer (timer_t timerid)
> {
>    if (timer_is_sigev_thread (timerid))
>      return timerid_to_timer (timerid)->ktimerid;
>    else
>      return (kernel_timer_t) ((uintptr_t) timerid);
> }
> 
> The library does a bit of magic with the pointers:
> 
> https://codebrowser.dev/glibc/glibc/sysdeps/unix/sysv/linux/kernel-posix-timers.h.html
> 
> But overall it checks the MSB bit of the pointer to figure out if it's
> kernel timer id which should be passed verbatim, or a structure that
> needs to be dereferenced.
> 
> Looking at the timer_gettime/speculative/6-1.c we do pass a pointer to
> the stack (instead of the invalid value) which on 32bit may be an
> address with the MSB bit set. So this triggers undefined behavior, since
> glibc thinks it's a pointer to it's internal data structure, but the
> real pointer the glibc exports as the timer is bit-shifted. Hence we
> access random and possibly invalid address. With some luck that address
> is accesible and contains non-zero data and we end up passing invalid
> timer ID to the kernel, but when I straced the test, the value was
> pretty much random.
> 

I was also trying to understand the sign bit usage and bit shifting
magic in this glibc code, causing this issue. Thanks for explaining
this clearly. I have send revised patch -
https://lore.kernel.org/ltp/20260831163310.137399-1-avinesh.kumar@suse.com/T/#u


Regards,
Avinesh

> With that in mind, we can fix the test with passing the BOGUSID instead
> of random stack pointer:
> 
> diff --git a/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-1.c b/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-1.c
> index d09c2f709..c35dd816f 100644
> --- a/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-1.c
> +++ b/testcases/open_posix_testsuite/conformance/interfaces/timer_gettime/speculative/6-1.c
> @@ -21,8 +21,7 @@ int test_main(int argc PTS_ATTRIBUTE_UNUSED, char **argv PTS_ATTRIBUTE_UNUSED)
>   {
>          timer_t tid;
>          struct itimerspec its;
> -       int tval = BOGUSTID;
> -       tid = (timer_t) & tval;
> +       tid = (timer_t) BOGUSTID;
>          if (timer_gettime(tid, &its) == -1) {
>                  if (EINVAL == errno) {
>                          printf("fcn returned -1 and errno==EINVAL\n");
> 



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