[PATCH] umad.c: memset() ib_user_mad_reg_req structure to 0 before invoking ioctl()

[PATCH] umad.c: memset() ib_user_mad_reg_req structure to 0 before invoking ioctl()

[sebastien dugue]

This fixes the following warning issued by valgrind:

==5287== Syscall param ioctl(generic) points to uninitialised byte(s)
==5287==    at 0x3C466D95D7: ioctl (in /lib64/libc-2.12.so)
==5287==    by 0x526C292: umad_register (umad.c:947)
==5287==    by 0x568D206: smp_engine_init (query_smp.c:228)
==5287==    by 0x5689F8F: ibnd_discover_fabric (ibnetdisc.c:537)
==5287==    by 0x411700: devmgr_discover_fabric (devmgr_discover.c:66)

Signed-off-by: Jean-Vincent Ficet <jean-vincent.ficet-6ktuUTfB/bM@public.gmane.org>

---

diff --git a/src/umad.c b/src/umad.c
index 45a9423..cac46a4 100644
--- a/src/umad.c
+++ b/src/umad.c
@@ -892,6 +892,7 @@ int umad_register_oui(int fd, int mgmt_class, uint8_t rmpp_version,
 		return -EINVAL;
 	}
 
+	memset(&req, 0, sizeof(req));
 	req.qpn = 1;
 	req.mgmt_class = mgmt_class;
 	req.mgmt_class_version = 1;
@@ -928,6 +929,7 @@ int umad_register(int fd, int mgmt_class, int mgmt_version,
 	    ("fd %d mgmt_class %u mgmt_version %u rmpp_version %d method_mask %p",
 	     fd, mgmt_class, mgmt_version, rmpp_version, method_mask);
 
+	memset(&req, 0, sizeof(req));
 	req.qpn = qp = (mgmt_class == 0x1 || mgmt_class == 0x81) ? 0 : 1;
 	req.mgmt_class = mgmt_class;
 	req.mgmt_class_version = mgmt_version;
-- 
1.7.1.rc2.7.g3e7f1

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Re: [PATCH] umad.c: memset() ib_user_mad_reg_req structure to 0 before invoking ioctl()

[Hal Rosenstock]

On 7/4/2011 5:53 AM, sebastien dugue wrote:
> 
> This fixes the following warning issued by valgrind:
> 
> ==5287== Syscall param ioctl(generic) points to uninitialised byte(s)
> ==5287==    at 0x3C466D95D7: ioctl (in /lib64/libc-2.12.so)
> ==5287==    by 0x526C292: umad_register (umad.c:947)
> ==5287==    by 0x568D206: smp_engine_init (query_smp.c:228)
> ==5287==    by 0x5689F8F: ibnd_discover_fabric (ibnetdisc.c:537)
> ==5287==    by 0x411700: devmgr_discover_fabric (devmgr_discover.c:66)
> 
> Signed-off-by: Jean-Vincent Ficet <jean-vincent.ficet-6ktuUTfB/bM@public.gmane.org>
> 
> ---
> 
> diff --git a/src/umad.c b/src/umad.c
> index 45a9423..cac46a4 100644
> --- a/src/umad.c
> +++ b/src/umad.c
> @@ -892,6 +892,7 @@ int umad_register_oui(int fd, int mgmt_class, uint8_t rmpp_version,
>  		return -EINVAL;
>  	}
>  
> +	memset(&req, 0, sizeof(req));
>  	req.qpn = 1;
>  	req.mgmt_class = mgmt_class;
>  	req.mgmt_class_version = 1;
> @@ -928,6 +929,7 @@ int umad_register(int fd, int mgmt_class, int mgmt_version,
>  	    ("fd %d mgmt_class %u mgmt_version %u rmpp_version %d method_mask %p",
>  	     fd, mgmt_class, mgmt_version, rmpp_version, method_mask);
>  
> +	memset(&req, 0, sizeof(req));
>  	req.qpn = qp = (mgmt_class == 0x1 || mgmt_class == 0x81) ? 0 : 1;
>  	req.mgmt_class = mgmt_class;
>  	req.mgmt_class_version = mgmt_version;

I think this is a "false positive" in valgrind. memset of the request
isn't really needed for either of these APIs as all input fields are
filled in by the caller and the only one which isn't is id which is an
output field.

-- Hal
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Re: [PATCH] umad.c: memset() ib_user_mad_reg_req structure to 0 beforeinvoking ioctl()

[sebastien dugue]

On Tue, 05 Jul 2011 07:41:17 -0400
Hal Rosenstock <hal-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org> wrote:

> On 7/4/2011 5:53 AM, sebastien dugue wrote:
> > 
> > This fixes the following warning issued by valgrind:
> > 
> > ==5287== Syscall param ioctl(generic) points to uninitialised byte(s)
> > ==5287==    at 0x3C466D95D7: ioctl (in /lib64/libc-2.12.so)
> > ==5287==    by 0x526C292: umad_register (umad.c:947)
> > ==5287==    by 0x568D206: smp_engine_init (query_smp.c:228)
> > ==5287==    by 0x5689F8F: ibnd_discover_fabric (ibnetdisc.c:537)
> > ==5287==    by 0x411700: devmgr_discover_fabric (devmgr_discover.c:66)
> > 
> > Signed-off-by: Jean-Vincent Ficet <jean-vincent.ficet-6ktuUTfB/bM@public.gmane.org>
> > 
> > ---
> > 
> > diff --git a/src/umad.c b/src/umad.c
> > index 45a9423..cac46a4 100644
> > --- a/src/umad.c
> > +++ b/src/umad.c
> > @@ -892,6 +892,7 @@ int umad_register_oui(int fd, int mgmt_class, uint8_t rmpp_version,
> >  		return -EINVAL;
> >  	}
> >  
> > +	memset(&req, 0, sizeof(req));
> >  	req.qpn = 1;
> >  	req.mgmt_class = mgmt_class;
> >  	req.mgmt_class_version = 1;
> > @@ -928,6 +929,7 @@ int umad_register(int fd, int mgmt_class, int mgmt_version,
> >  	    ("fd %d mgmt_class %u mgmt_version %u rmpp_version %d method_mask %p",
> >  	     fd, mgmt_class, mgmt_version, rmpp_version, method_mask);
> >  
> > +	memset(&req, 0, sizeof(req));
> >  	req.qpn = qp = (mgmt_class == 0x1 || mgmt_class == 0x81) ? 0 : 1;
> >  	req.mgmt_class = mgmt_class;
> >  	req.mgmt_class_version = mgmt_version;
> 
> I think this is a "false positive" in valgrind. memset of the request
> isn't really needed for either of these APIs as all input fields are
> filled in by the caller and the only one which isn't is id which is an
> output field.

  Ok then, it's no needed.

  Thanks,

  Sébastien.

> 
> -- Hal
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Re: [PATCH] umad.c: memset() ib_user_mad_reg_req structure to 0 before invoking ioctl()

[Bart Van Assche]

On Mon, Jul 4, 2011 at 11:53 AM, sebastien dugue
<sebastien.dugue-6ktuUTfB/bM@public.gmane.org> wrote:
>
> This fixes the following warning issued by valgrind:
>
> ==5287== Syscall param ioctl(generic) points to uninitialised byte(s)
> ==5287==    at 0x3C466D95D7: ioctl (in /lib64/libc-2.12.so)
> ==5287==    by 0x526C292: umad_register (umad.c:947)
> ==5287==    by 0x568D206: smp_engine_init (query_smp.c:228)
> ==5287==    by 0x5689F8F: ibnd_discover_fabric (ibnetdisc.c:537)
> ==5287==    by 0x411700: devmgr_discover_fabric (devmgr_discover.c:66)
>
> Signed-off-by: Jean-Vincent Ficet <jean-vincent.ficet-6ktuUTfB/bM@public.gmane.org>
>
> ---
>
> diff --git a/src/umad.c b/src/umad.c
> index 45a9423..cac46a4 100644
> --- a/src/umad.c
> +++ b/src/umad.c
> @@ -892,6 +892,7 @@ int umad_register_oui(int fd, int mgmt_class, uint8_t rmpp_version,
>                return -EINVAL;
>        }
>
> +       memset(&req, 0, sizeof(req));
>        req.qpn = 1;
>        req.mgmt_class = mgmt_class;
>        req.mgmt_class_version = 1;
> @@ -928,6 +929,7 @@ int umad_register(int fd, int mgmt_class, int mgmt_version,
>            ("fd %d mgmt_class %u mgmt_version %u rmpp_version %d method_mask %p",
>             fd, mgmt_class, mgmt_version, rmpp_version, method_mask);
>
> +       memset(&req, 0, sizeof(req));
>        req.qpn = qp = (mgmt_class == 0x1 || mgmt_class == 0x81) ? 0 : 1;
>        req.mgmt_class = mgmt_class;
>        req.mgmt_class_version = mgmt_version;

A possible alternative approach is to develop a patch for Valgrind
that makes Valgrind ignore padding fields and/or output fields in the
pre-ioctl check. See also PRE(sys_ioctl) in source file
coregrind/m_syswrap/syswrap-linux.c or the documentation file
README_MISSING_SYSCALL_OR_IOCTL.

Bart.
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Re: [PATCH] umad.c: memset() ib_user_mad_reg_req structure to 0before invoking ioctl()

[sebastien dugue]

On Tue, 5 Jul 2011 20:17:18 +0200
Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org> wrote:

> On Mon, Jul 4, 2011 at 11:53 AM, sebastien dugue
> <sebastien.dugue-6ktuUTfB/bM@public.gmane.org> wrote:
> >
> > This fixes the following warning issued by valgrind:
> >
> > ==5287== Syscall param ioctl(generic) points to uninitialised byte(s)
> > ==5287==    at 0x3C466D95D7: ioctl (in /lib64/libc-2.12.so)
> > ==5287==    by 0x526C292: umad_register (umad.c:947)
> > ==5287==    by 0x568D206: smp_engine_init (query_smp.c:228)
> > ==5287==    by 0x5689F8F: ibnd_discover_fabric (ibnetdisc.c:537)
> > ==5287==    by 0x411700: devmgr_discover_fabric (devmgr_discover.c:66)
> >
> > Signed-off-by: Jean-Vincent Ficet <jean-vincent.ficet-6ktuUTfB/bM@public.gmane.org>
> >
> > ---
> >
> > diff --git a/src/umad.c b/src/umad.c
> > index 45a9423..cac46a4 100644
> > --- a/src/umad.c
> > +++ b/src/umad.c
> > @@ -892,6 +892,7 @@ int umad_register_oui(int fd, int mgmt_class, uint8_t rmpp_version,
> >                return -EINVAL;
> >        }
> >
> > +       memset(&req, 0, sizeof(req));
> >        req.qpn = 1;
> >        req.mgmt_class = mgmt_class;
> >        req.mgmt_class_version = 1;
> > @@ -928,6 +929,7 @@ int umad_register(int fd, int mgmt_class, int mgmt_version,
> >            ("fd %d mgmt_class %u mgmt_version %u rmpp_version %d method_mask %p",
> >             fd, mgmt_class, mgmt_version, rmpp_version, method_mask);
> >
> > +       memset(&req, 0, sizeof(req));
> >        req.qpn = qp = (mgmt_class == 0x1 || mgmt_class == 0x81) ? 0 : 1;
> >        req.mgmt_class = mgmt_class;
> >        req.mgmt_class_version = mgmt_version;
> 
> A possible alternative approach is to develop a patch for Valgrind
> that makes Valgrind ignore padding fields and/or output fields in the
> pre-ioctl check. See also PRE(sys_ioctl) in source file
> coregrind/m_syswrap/syswrap-linux.c or the documentation file
> README_MISSING_SYSCALL_OR_IOCTL.

  Could be, but this is largely out of scope for me and I can live
with the warning knowing it's a false positive.

  Thanks,

  Sébastien.

> 
> Bart.
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