Date: Tue, 12 Nov 2013 20:42:39 +0800 (SGT) From: Prashanth Kumar <pra_udupi@yahoo.co.in> To: "freebsd-dtrace@freebsd.org" <freebsd-dtrace@freebsd.org> Subject: Fw: your mail Message-ID: <1384260159.73063.YahooMailNeo@web192605.mail.sg3.yahoo.com> In-Reply-To: <1384258564.17896.YahooMailNeo@web192603.mail.sg3.yahoo.com> References: <1384228985.51085.YahooMailNeo@web192604.mail.sg3.yahoo.com> <20131112041805.GA76413@raichu> <1384258564.17896.YahooMailNeo@web192603.mail.sg3.yahoo.com>
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Hi Mark=0A=0A---------------------------------------=0A/* scan.c */=0A=0A#i=
nclude <stdio.h>=0A=0Aint main()=0A{=0A=A0=A0=A0 int str[10];=0A=0A=A0=A0=
=A0 if (scanf("%s", str) > 0)=0A=A0=A0=A0 =A0=A0=A0 printf("name %s\n", str=
);=0A=0A=A0=A0=A0 return 0;=0A}=0A-----------------------------=0A> "dtrace=
-n 'pid$target:::entry' -c scanf"=0A=0Aif you run the above dtrace command=
on the program , dtrace will not exit and hung in input.=0A=0ARegards=0APr=
ashanth=0A=0A=0A=0A=0A=0A=0AOn Tuesday, 12 November 2013 8:18 AM, Mark John=
ston <markj@freebsd.org> wrote:=0A =0AOn Tue, Nov 12, 2013 at 12:03:05PM +0=
800, Prashanth Kumar wrote:=0A> Hello, =0A> =0A> I had been doing some work=
on the pid provider in Dtrace.=0A=0AHi Prashanth,=0A=0AI've been going thr=
ough your patches and committing them as time permits.=0A=0A>=A0 I have mad=
e a few modification=0A> =A0so that it will list all the functions used in =
the program as seen in Solaris or MacOSX.=0A> =A0Presently in FreeBSD, you =
have to name each functions you have to probe in the program. For=0A> =A0ex=
ample "dtrace -n 'pid$target:program::entry' -c ./program" will list all th=
e functions called=0A> =A0in the=0A program.This modification was made in l=
ibproc library(proc_sym.c).=0A=0AThis has been fixed:=0A=0Ahttp://svnweb.fr=
eebsd.org/base?view=3Drevision&revision=3D257300=0Ahttp://svnweb.freebsd.or=
g/base?view=3Drevision&revision=3D258000=0A=0A> =0A> =A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0 Also while creating probe points for return probe type, any fu=
nction with more than one return=0A> =A0path will fail.This is because "fas=
ttrap_probe_spec_t" type variable is not fully copied into the=0A> =A0kerne=
l in fasttrap_ioctl() function.I have modified in line with Solaris code=0A=
where the copying=A0 is=0A> =A0done manually by Dtrace, rather than the ke=
rnel.(fasttap.c, fasttrap.h)=0A=0AI'm working on this one.=0A=0A> =A0Also i=
n "fasttrap_pid_probe()" (fasttrap_isa.c) for the case of "FASTTRAP_T_PUSHL=
_EBP", the ebp register=0A> =A0has to be copied to the stack not esp.=0A> =
=A0=A0=A0=A0=A0=A0=A0 I had attached the patch files for review.=0A=0AThis =
has been fixed:=0A=0Ahttp://svnweb.freebsd.org/base?view=3Drevision&revisio=
n=3D257679=0Ahttp://svnweb.freebsd.org/base?view=3Drevision&revision=3D2571=
43=0A=0A> =0A> =A0One other issue i noticed is that if the program being tr=
aced uses Thread Local Storage than=0A> =A0for the case of entry probe, it =
will hang in ___tls_get_addr function in ld-elf.so.=0A> =A0If you use scanf=
or fscanf in your program you can notice this behaviour. This i believe is=
due to=0A> =A0Dtrace using gs segment register to point to the scratch spa=
ce, and TLS also loading the thread variable=0A> =A0from gs register.=0A=0A=
I haven't been able to reproduce this one yet. If you can send me a=0Aprogr=
am and D script that does the trick, that'd be very helpful.=0A=0A> =0A> =
=A0if you change the following code in fasttrap_isa.c=0A> =A0<code>=0A> =A0=
#ifdef __i386__=0A> =A0=A0=A0=A0=A0=A0=A0=A0 addr =3D USD_GETBASE(&curthrea=
d->td_pcb->pcb_gsd);=0A> =A0#else=0A> =A0=A0=A0=A0=A0=A0=A0=A0 addr =3D cur=
thread->td_pcb->pcb_gsbase;=0A> =A0#endif=0A> =A0=A0=A0=A0=A0=A0=A0=A0 addr=
+=3D sizeof (void *);=A0 =A0=0A> =A0</code>=0A> =0A> =A0to=0A> =0A> =A0<co=
de>=0A> =A0#ifdef __i386__=0A> =A0=A0=A0=A0=A0=A0=A0=A0 addr =3D USD_GETBAS=
E(&curthread->td_pcb->pcb_gsd);=0A> =A0#else=0A> =A0=A0=A0=A0=A0=A0=A0=A0 a=
ddr =3D curthread->td_pcb->pcb_gsbase;=0A> =A0#endif=0A>=0A =A0=A0=A0=A0=A0=
=A0=A0=A0 addr +=3D sizeof (void *) * 3;=A0 =A0=0A> =A0</code>=0A> =0A> =A0=
the Dtrace will not hang. I am not sure what is happening here and=0A> =A0w=
hether this is the correct solution.=0A=0ANeither am I. :)=0A=0A=0A> =A0Thi=
s changes were made in FreeBSD 9.2-386-RELEASE. I applied the above patches=
on=0A> =A0FreeBSD 10-BETA (with some manual work) and it was still working=
.=0A> _______________________________________________=0A> freebsd-dtrace@fr=
eebsd.org mailing list=0A> https://lists.freebsd.org/mailman/listinfo/freeb=
sd-dtrace=0A> To unsubscribe, send any mail to "freebsd-dtrace-unsubscribe@=
freebsd.org=0A"
From owner-freebsd-dtrace@FreeBSD.ORG Tue Nov 12 16:01:19 2013
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Subject: bug in dtrace mips fbt
From: Howard Su <howard0su@gmail.com>
To: freebsd-dtrace@freebsd.org
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I notice a small error in fbt provider of mips.
In file: cddl/dev/fbt/powerpc.c
222: limit = (u_int32_t *) symval->value + symval->size;
this should be limit = (u_int32_t *) ((u_int8_t*)symval->value +
symval->size);
I don't have powerpc to test. anyone can test this and fix it?
-Howard
--
-Howard
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