Date: Sun, 11 Jul 2010 08:33:10 -0700 From: mdf@FreeBSD.org To: Gabor Kovesdan <gabor@freebsd.org> Cc: Dimitry Andric <dimitry@andric.com>, FreeBSD Hackers <hackers@freebsd.org> Subject: Re: strange problem with int64_t variables Message-ID: <AANLkTil_AEicC4sWD2M7-FwTl2OO5KKGk3P7TVynh2wP@mail.gmail.com> In-Reply-To: <4C39DBFF.2000307@FreeBSD.org> References: <4C39D92F.4050605@FreeBSD.org> <4C39DB09.6010808@andric.com> <4C39DBFF.2000307@FreeBSD.org>
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On Sun, Jul 11, 2010 at 7:58 AM, Gabor Kovesdan <gabor@freebsd.org> wrote:
> Em 2010.07.11. 16:54, Dimitry Andric escreveu:
>>
>> On 2010-07-11 16:46, Gabor Kovesdan wrote:
>>
>>>
>>> I have two int64_t variables in kernel code, first is stored internally
>>> and the second one is passed from a syscall argument. When I print them
>>> with printf %lld modifier, the internal one behaves correctly but the
>>> other one I pass from a syscall has a corrupted value. If I pass 1, it
>>> prints out 3735348794091372545. I'm not doing anything special with it
>>> just reading it out from the struct that was generated with make sysent=
.
>>>
>>
>> Since 3735348794091372545 is 0x33d69ff000000001, it looks like the upper
>> word got corrupted somehow. =A0Maybe some part of it got non-atomically
>> assigned? =A0Maybe the wrong word was read? =A0It is hard to tell withou=
t
>> code... =A0:)
>>
>
> Userland syscall calling:
>
> killjob(getjid(), SIGINT); =A0//getjid() returns 1 this case, whose type =
is
> jid_t
>
> Kernel code:
>
> int
> killjob(struct thread *td, struct killjob_args *uap)
> {
> =A0 =A0 =A0 =A0struct jobentry *jp, *jtmp;
> =A0 =A0 =A0 =A0struct procentry *pp, *ptmp;
>
> =A0 =A0 =A0 =A0JOBLIST_bWLOCK;
> =A0 =A0 =A0 =A0LIST_FOREACH_SAFE(jp,&irix_joblist, entries, jtmp) {
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0if (jp->jid =3D=3D uap->jid) {
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0/* never reached code, com=
parison always fail because
> of corrupted value */
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0}
> =A0 =A0 =A0 =A0}
> =A0 =A0 =A0 =A0JOBLIST_WUNLOCK;
>
> =A0 =A0 =A0 =A0/* not such job */
> =A0 =A0 =A0 =A0td->td_retval[0] =3D -1;
> =A0 =A0 =A0 =A0return (ENOJOB);
> }
What does struct killjob_args look like?
Is this syscall defined in a module, or an addition to the kernel's
syscalls.master?
Is the user-space 32-bit or 64-bit? What about the kernel?
Thanks,
matthew
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