From: Jinrong Liang <[email protected]>
The following warning appears when executing:
make -C tools/testing/selftests/kvm
rseq_test.c: In function ‘main’:
rseq_test.c:237:33: warning: implicit declaration of function ‘gettid’; did you mean ‘getgid’? [-Wimplicit-function-declaration]
(void *)(unsigned long)gettid());
^~~~~~
getgid
/usr/bin/ld: /tmp/ccr5mMko.o: in function `main':
../kvm/tools/testing/selftests/kvm/rseq_test.c:237: undefined reference to `gettid'
collect2: error: ld returned 1 exit status
make: *** [../lib.mk:173: ../kvm/tools/testing/selftests/kvm/rseq_test] Error 1
Use the more compatible syscall(SYS_gettid) instead of gettid() to fix it.
More subsequent reuse may cause it to be wrapped in a lib file.
Signed-off-by: Jinrong Liang <[email protected]>
---
tools/testing/selftests/kvm/rseq_test.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/kvm/rseq_test.c b/tools/testing/selftests/kvm/rseq_test.c
index a54d4d05a058..299d316cc759 100644
--- a/tools/testing/selftests/kvm/rseq_test.c
+++ b/tools/testing/selftests/kvm/rseq_test.c
@@ -229,7 +229,7 @@ int main(int argc, char *argv[])
ucall_init(vm, NULL);
pthread_create(&migration_thread, NULL, migration_worker,
- (void *)(unsigned long)gettid());
+ (void *)(unsigned long)syscall(SYS_gettid));
for (i = 0; !done; i++) {
vcpu_run(vcpu);
--
2.37.1
On Tue, Aug 02, 2022 at 03:12:40PM +0800, Jinrong Liang wrote:
> From: Jinrong Liang <[email protected]>
>
> The following warning appears when executing:
> make -C tools/testing/selftests/kvm
>
> rseq_test.c: In function ‘main’:
> rseq_test.c:237:33: warning: implicit declaration of function ‘gettid’; did you mean ‘getgid’? [-Wimplicit-function-declaration]
> (void *)(unsigned long)gettid());
> ^~~~~~
> getgid
> /usr/bin/ld: /tmp/ccr5mMko.o: in function `main':
> ../kvm/tools/testing/selftests/kvm/rseq_test.c:237: undefined reference to `gettid'
> collect2: error: ld returned 1 exit status
> make: *** [../lib.mk:173: ../kvm/tools/testing/selftests/kvm/rseq_test] Error 1
The man page says we need
#define _GNU_SOURCE
#include <unistd.h>
which rseq_test.c doesn't have. We have _GNU_SOURCE, but not unistd.h.
IOW, I think this patch can be
diff --git a/tools/testing/selftests/kvm/rseq_test.c b/tools/testing/selftests/kvm/rseq_test.c
index a54d4d05a058..8d3d5eab5e19 100644
--- a/tools/testing/selftests/kvm/rseq_test.c
+++ b/tools/testing/selftests/kvm/rseq_test.c
@@ -9,6 +9,7 @@
#include <string.h>
#include <signal.h>
#include <syscall.h>
+#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/sysinfo.h>
#include <asm/barrier.h>
Thanks,
drew
>
> Use the more compatible syscall(SYS_gettid) instead of gettid() to fix it.
> More subsequent reuse may cause it to be wrapped in a lib file.
>
> Signed-off-by: Jinrong Liang <[email protected]>
> ---
> tools/testing/selftests/kvm/rseq_test.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/kvm/rseq_test.c b/tools/testing/selftests/kvm/rseq_test.c
> index a54d4d05a058..299d316cc759 100644
> --- a/tools/testing/selftests/kvm/rseq_test.c
> +++ b/tools/testing/selftests/kvm/rseq_test.c
> @@ -229,7 +229,7 @@ int main(int argc, char *argv[])
> ucall_init(vm, NULL);
>
> pthread_create(&migration_thread, NULL, migration_worker,
> - (void *)(unsigned long)gettid());
> + (void *)(unsigned long)syscall(SYS_gettid));
>
> for (i = 0; !done; i++) {
> vcpu_run(vcpu);
> --
> 2.37.1
>
My ldd version is (GNU libc) 2.28, and I get a compilation error in this case.
But I use another ldd (Ubuntu GLIBC 2.31-0ubuntu9.2) 2.31 is compiling fine.
This shows that compilation errors may occur in different GNU libc environments.
Would it be more appropriate to use syscall for better compatibility?
Thanks,
Jinrong Liang
Andrew Jones <[email protected]> 于2022年8月2日周二 23:08写道：
>
> On Tue, Aug 02, 2022 at 03:12:40PM +0800, Jinrong Liang wrote:
> > From: Jinrong Liang <[email protected]>
> >
> > The following warning appears when executing:
> > make -C tools/testing/selftests/kvm
> >
> > rseq_test.c: In function ‘main’:
> > rseq_test.c:237:33: warning: implicit declaration of function ‘gettid’; did you mean ‘getgid’? [-Wimplicit-function-declaration]
> > (void *)(unsigned long)gettid());
> > ^~~~~~
> > getgid
> > /usr/bin/ld: /tmp/ccr5mMko.o: in function `main':
> > ../kvm/tools/testing/selftests/kvm/rseq_test.c:237: undefined reference to `gettid'
> > collect2: error: ld returned 1 exit status
> > make: *** [../lib.mk:173: ../kvm/tools/testing/selftests/kvm/rseq_test] Error 1
>
> The man page says we need
>
> #define _GNU_SOURCE
> #include <unistd.h>
>
> which rseq_test.c doesn't have. We have _GNU_SOURCE, but not unistd.h.
> IOW, I think this patch can be
>
> diff --git a/tools/testing/selftests/kvm/rseq_test.c b/tools/testing/selftests/kvm/rseq_test.c
> index a54d4d05a058..8d3d5eab5e19 100644
> --- a/tools/testing/selftests/kvm/rseq_test.c
> +++ b/tools/testing/selftests/kvm/rseq_test.c
> @@ -9,6 +9,7 @@
> #include <string.h>
> #include <signal.h>
> #include <syscall.h>
> +#include <unistd.h>
> #include <sys/ioctl.h>
> #include <sys/sysinfo.h>
> #include <asm/barrier.h>
>
> Thanks,
> drew
>
> >
> > Use the more compatible syscall(SYS_gettid) instead of gettid() to fix it.
> > More subsequent reuse may cause it to be wrapped in a lib file.
> >
> > Signed-off-by: Jinrong Liang <[email protected]>
> > ---
> > tools/testing/selftests/kvm/rseq_test.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/tools/testing/selftests/kvm/rseq_test.c b/tools/testing/selftests/kvm/rseq_test.c
> > index a54d4d05a058..299d316cc759 100644
> > --- a/tools/testing/selftests/kvm/rseq_test.c
> > +++ b/tools/testing/selftests/kvm/rseq_test.c
> > @@ -229,7 +229,7 @@ int main(int argc, char *argv[])
> > ucall_init(vm, NULL);
> >
> > pthread_create(&migration_thread, NULL, migration_worker,
> > - (void *)(unsigned long)gettid());
> > + (void *)(unsigned long)syscall(SYS_gettid));
> >
> > for (i = 0; !done; i++) {
> > vcpu_run(vcpu);
> > --
> > 2.37.1
> >
On Wed, Aug 03, 2022 at 09:58:51PM +0800, Jinrong Liang wrote:
> My ldd version is (GNU libc) 2.28, and I get a compilation error in this case.
> But I use another ldd (Ubuntu GLIBC 2.31-0ubuntu9.2) 2.31 is compiling fine.
> This shows that compilation errors may occur in different GNU libc environments.
> Would it be more appropriate to use syscall for better compatibility?
OK, it's a pity, but no big deal to use syscall().
Reviewed-by: Andrew Jones <[email protected]>
Thanks,
drew
On Wed, Aug 03, 2022, Andrew Jones wrote:
> On Wed, Aug 03, 2022 at 09:58:51PM +0800, Jinrong Liang wrote:
> > My ldd version is (GNU libc) 2.28, and I get a compilation error in this case.
> > But I use another ldd (Ubuntu GLIBC 2.31-0ubuntu9.2) 2.31 is compiling fine.
> > This shows that compilation errors may occur in different GNU libc environments.
> > Would it be more appropriate to use syscall for better compatibility?
>
> OK, it's a pity, but no big deal to use syscall().
Ya, https://man7.org/linux/man-pages/man2/gettid.2.html says:
The gettid() system call first appeared on Linux in kernel 2.4.11. Library
support was added in glibc 2.30.
But there are already two other instances of syscall(SYS_gettid) in KVM selftests,
tools/testing/selftests/kvm/lib/assert.c even adds a _gettid() wrapper.
So rather than having to remember (or discover) to use syscall(SYS_gettid), I wonder
if it's possible to conditionally define gettid()? E.g. check for GLIBC version?
Or do
#define gettid() syscall(SYS_gettid)
so that it's always available and simply overrides the library's gettid() if it's
provided?
On Wed, Aug 03, 2022 at 04:10:53PM +0000, Sean Christopherson wrote:
> On Wed, Aug 03, 2022, Andrew Jones wrote:
> > On Wed, Aug 03, 2022 at 09:58:51PM +0800, Jinrong Liang wrote:
> > > My ldd version is (GNU libc) 2.28, and I get a compilation error in this case.
> > > But I use another ldd (Ubuntu GLIBC 2.31-0ubuntu9.2) 2.31 is compiling fine.
> > > This shows that compilation errors may occur in different GNU libc environments.
> > > Would it be more appropriate to use syscall for better compatibility?
> >
> > OK, it's a pity, but no big deal to use syscall().
>
> Ya, https://man7.org/linux/man-pages/man2/gettid.2.html says:
>
> The gettid() system call first appeared on Linux in kernel 2.4.11. Library
> support was added in glibc 2.30.
>
> But there are already two other instances of syscall(SYS_gettid) in KVM selftests,
> tools/testing/selftests/kvm/lib/assert.c even adds a _gettid() wrapper.
Ha! And I found four more in selftests...
testing/selftests/powerpc/include/utils.h
testing/selftests/proc/proc.h
testing/selftests/rseq/param_test.c
testing/selftests/sched/cs_prctl_test.c
and even more in tools...
>
> So rather than having to remember (or discover) to use syscall(SYS_gettid), I wonder
> if it's possible to conditionally define gettid()? E.g. check for GLIBC version?
> Or do
>
> #define gettid() syscall(SYS_gettid)
>
> so that it's always available and simply overrides the library's gettid() if it's
> provided?
Sounds good to me. Now the question is where to put it? kvm_util.h,
test_util.h, or maybe we should create a new header just for stuff
like this?
It doesn't really "fit" in kvm_util.h, but if we put it there, then we
greatly reduce the chance that we'll have to revisit this issue again.
We could also create a new header just for stuff like this and then
include that from kvm_util.h...
Thanks,
drew
On Wed, Aug 03, 2022, Andrew Jones wrote:
> On Wed, Aug 03, 2022 at 04:10:53PM +0000, Sean Christopherson wrote:
> > On Wed, Aug 03, 2022, Andrew Jones wrote:
> > > On Wed, Aug 03, 2022 at 09:58:51PM +0800, Jinrong Liang wrote:
> > > > My ldd version is (GNU libc) 2.28, and I get a compilation error in this case.
> > > > But I use another ldd (Ubuntu GLIBC 2.31-0ubuntu9.2) 2.31 is compiling fine.
> > > > This shows that compilation errors may occur in different GNU libc environments.
> > > > Would it be more appropriate to use syscall for better compatibility?
> > >
> > > OK, it's a pity, but no big deal to use syscall().
> >
> > Ya, https://man7.org/linux/man-pages/man2/gettid.2.html says:
> >
> > The gettid() system call first appeared on Linux in kernel 2.4.11. Library
> > support was added in glibc 2.30.
> >
> > But there are already two other instances of syscall(SYS_gettid) in KVM selftests,
> > tools/testing/selftests/kvm/lib/assert.c even adds a _gettid() wrapper.
>
> Ha! And I found four more in selftests...
>
> testing/selftests/powerpc/include/utils.h
> testing/selftests/proc/proc.h
> testing/selftests/rseq/param_test.c
> testing/selftests/sched/cs_prctl_test.c
>
> and even more in tools...
Ha, and tools/testing/selftests/sched/cs_prctl_test.c even has the GLIBC crud.
#if __GLIBC_PREREQ(2, 30) == 0
#include <sys/syscall.h>
static pid_t gettid(void)
{
return syscall(SYS_gettid);
}
#endif
> > So rather than having to remember (or discover) to use syscall(SYS_gettid), I wonder
> > if it's possible to conditionally define gettid()? E.g. check for GLIBC version?
> > Or do
> >
> > #define gettid() syscall(SYS_gettid)
> >
> > so that it's always available and simply overrides the library's gettid() if it's
> > provided?
>
> Sounds good to me. Now the question is where to put it? kvm_util.h,
> test_util.h, or maybe we should create a new header just for stuff
> like this?
tools/include/uapi/linux/syscall.h?
Kind of dirty, but not thaaaat dirty.
On Tue, Aug 02, 2022, Jinrong Liang wrote:
> From: Jinrong Liang <[email protected]>
>
> The following warning appears when executing:
> make -C tools/testing/selftests/kvm
>
> rseq_test.c: In function ‘main’:
> rseq_test.c:237:33: warning: implicit declaration of function ‘gettid’; did you mean ‘getgid’? [-Wimplicit-function-declaration]
> (void *)(unsigned long)gettid());
> ^~~~~~
> getgid
> /usr/bin/ld: /tmp/ccr5mMko.o: in function `main':
> ../kvm/tools/testing/selftests/kvm/rseq_test.c:237: undefined reference to `gettid'
> collect2: error: ld returned 1 exit status
> make: *** [../lib.mk:173: ../kvm/tools/testing/selftests/kvm/rseq_test] Error 1
>
> Use the more compatible syscall(SYS_gettid) instead of gettid() to fix it.
> More subsequent reuse may cause it to be wrapped in a lib file.
>
> Signed-off-by: Jinrong Liang <[email protected]>
> ---
Reviewed-by: Sean Christopherson <[email protected]>
Paolo, do you want to grab this for 6.0? It doesn't look like we're going to have
a more elegant solution anytime soon...
On 07/09/2022 17:01, Sean Christopherson wrote:
> On Tue, Aug 02, 2022, Jinrong Liang wrote:
>> From: Jinrong Liang <[email protected]>
>>
>> The following warning appears when executing:
>> make -C tools/testing/selftests/kvm
>>
>> rseq_test.c: In function ‘main’:
>> rseq_test.c:237:33: warning: implicit declaration of function ‘gettid’; did you mean ‘getgid’? [-Wimplicit-function-declaration]
>> (void *)(unsigned long)gettid());
>> ^~~~~~
>> getgid
>> /usr/bin/ld: /tmp/ccr5mMko.o: in function `main':
>> ../kvm/tools/testing/selftests/kvm/rseq_test.c:237: undefined reference to `gettid'
>> collect2: error: ld returned 1 exit status
>> make: *** [../lib.mk:173: ../kvm/tools/testing/selftests/kvm/rseq_test] Error 1
>>
>> Use the more compatible syscall(SYS_gettid) instead of gettid() to fix it.
>> More subsequent reuse may cause it to be wrapped in a lib file.
>>
>> Signed-off-by: Jinrong Liang <[email protected]>
>> ---
>
> Reviewed-by: Sean Christopherson <[email protected]>
>
Can a 'Cc: [email protected]' be added also as e923b0537d28 got
backported to v5.15.58
Reviewed-by: Liam Merwick <[email protected]>
>
> Paolo, do you want to grab this for 6.0? It doesn't look like we're going to have
> a more elegant solution anytime soon...
On 2022/9/8 00:54, Liam Merwick wrote:
> On 07/09/2022 17:01, Sean Christopherson wrote:
>> On Tue, Aug 02, 2022, Jinrong Liang wrote:
>>> From: Jinrong Liang <[email protected]>
>>>
>>> The following warning appears when executing:
>>> make -C tools/testing/selftests/kvm
>>>
>>> rseq_test.c: In function ‘main’:
>>> rseq_test.c:237:33: warning: implicit declaration of function
>>> ‘gettid’; did you mean ‘getgid’? [-Wimplicit-function-declaration]
>>> (void *)(unsigned long)gettid());
>>> ^~~~~~
>>> getgid
>>> /usr/bin/ld: /tmp/ccr5mMko.o: in function `main':
>>> ../kvm/tools/testing/selftests/kvm/rseq_test.c:237: undefined
>>> reference to `gettid'
>>> collect2: error: ld returned 1 exit status
>>> make: *** [../lib.mk:173:
>>> ../kvm/tools/testing/selftests/kvm/rseq_test] Error 1
>>>
>>> Use the more compatible syscall(SYS_gettid) instead of gettid() to
>>> fix it.
>>> More subsequent reuse may cause it to be wrapped in a lib file.
>>>
>>> Signed-off-by: Jinrong Liang <[email protected]>
>>> ---
>>
>> Reviewed-by: Sean Christopherson <[email protected]>
>>
>
> Can a 'Cc: [email protected]' be added also as e923b0537d28 got
> backported to v5.15.58
>
> Reviewed-by: Liam Merwick <[email protected]>
>
>
>>
>> Paolo, do you want to grab this for 6.0? It doesn't look like we're
>> going to have
>> a more elegant solution anytime soon...
>
Ping?
On Fri, Sep 16, 2022 at 3:03 AM JinrongLiang <[email protected]> wrote:
>
>
>
> On 2022/9/8 00:54, Liam Merwick wrote:
> > On 07/09/2022 17:01, Sean Christopherson wrote:
> >> On Tue, Aug 02, 2022, Jinrong Liang wrote:
> >>> From: Jinrong Liang <[email protected]>
> >>>
> >>> The following warning appears when executing:
> >>> make -C tools/testing/selftests/kvm
> >>>
> >>> rseq_test.c: In function ‘main’:
> >>> rseq_test.c:237:33: warning: implicit declaration of function
> >>> ‘gettid’; did you mean ‘getgid’? [-Wimplicit-function-declaration]
> >>> (void *)(unsigned long)gettid());
> >>> ^~~~~~
> >>> getgid
> >>> /usr/bin/ld: /tmp/ccr5mMko.o: in function `main':
> >>> ../kvm/tools/testing/selftests/kvm/rseq_test.c:237: undefined
> >>> reference to `gettid'
> >>> collect2: error: ld returned 1 exit status
> >>> make: *** [../lib.mk:173:
> >>> ../kvm/tools/testing/selftests/kvm/rseq_test] Error 1
> >>>
> >>> Use the more compatible syscall(SYS_gettid) instead of gettid() to
> >>> fix it.
> >>> More subsequent reuse may cause it to be wrapped in a lib file.
> >>>
> >>> Signed-off-by: Jinrong Liang <[email protected]>
> >>> ---
> >>
> >> Reviewed-by: Sean Christopherson <[email protected]>
> >>
> >
> > Can a 'Cc: [email protected]' be added also as e923b0537d28 got
> > backported to v5.15.58
> >
> > Reviewed-by: Liam Merwick <[email protected]>
> >
> >
> >>
> >> Paolo, do you want to grab this for 6.0? It doesn't look like we're
> >> going to have
> >> a more elegant solution anytime soon...
> >
> Ping?
+1, please grab this. Every new branch I create (for new development
and to review upstream code) I have to remember to cherry-pick this
patch in because I use Clang.
Queued, thanks.
Paolo