Date: Fri, 26 Sep 2014 06:58:44 -0700 From: madhava gaikwad <alex_madhava@yahoo.com> To: Mark Johnston <markj@FreeBSD.org> Cc: "freebsd-dtrace@freebsd.org" <freebsd-dtrace@freebsd.org> Subject: Re: [freebsd 9.2] dtrace causes hung process when called for strlen Message-ID: <1411739924.65670.YahooMailNeo@web122006.mail.ne1.yahoo.com> In-Reply-To: <20140926070831.GA56476@charmander.Belkin> References: <1411705375.19660.YahooMailNeo@web122002.mail.ne1.yahoo.com> <20140926070831.GA56476@charmander.Belkin>
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Thanks for the reply Mark. So in Nutshell, 9.2 is not the version completely supporting dtrace functionality. I am not sure if I can get next freebsd version for my product that quick. I will try to add more debugs into those functions and will see if I can get anything in short time.
Again thanks for your help and pointers.
Cheers,
Madhava
On Friday, September 26, 2014 12:38 PM, Mark Johnston <markj@FreeBSD.org> wrote:
On Thu, Sep 25, 2014 at 09:22:55PM -0700, madhava gaikwad via freebsd-dtrace wrote:
> Hello Experts,
>
> I am a freebsd newbie and having a strange issue on freebsd 9.2 (It is AMD64
> machine).I am not able to dtrace few libc functions. For example I am able to
> dtrace strdup, but calling dtrace for strlen causes hung process. It is 100 % percent repro-able. Is it
> expected?
Hi,
I'm not sure what the exact problem is in your case, but 9.2 is missing
a large number of fixes that have gone into userland DTrace support. Without
them, I don't expect it to work reliably. I suggest trying 9.3 or the
soon-to-be-released 10.1 instead. If you continue to run into problems
after upgrading, please let us know.
Thanks,
-Mark
>
> Problem: high cpu, and hung process under dtrace when
> calling for strlen. Somehow my sample program don’t crash, but the real
> application crashes when I send ctrl+C to application running under dtrace.
>
> PID USERNAME THR PRI NICE SIZE RES STATE TIME WCPU COMMAND
> 25264 root 2 85 0 61268K 15244K RUN 0:26 43.99% dtrace
> 25265 root 1 47 0 10136K 1368K STOP 0:18 31.98% sample
>
> Sample program
> $ cat sample.c
> #include <stdio.h>
> #include <string.h>
>
> int main (void) {
> int i = 0;
> for (; i < 3; i++) {
> printf("calling strlen: %d\n", strlen("foobar"));
> printf("calling strdup: %s\n", strdup("foobar"));
> }
> return 0;
> }
>
> The sample Makefile
> $cat Makefile
> CFLAGS=-I.
> CFLAGS+=-fno-omit-frame-pointer -g
>
> samplemake: sample.c
> gcc -o
> sample sample.c -I.
> $
>
> The sample D files
> $ cat strdup.d
> pid$target::strdup:return
> {
> trace (arg1);
> }
> $ cat strlen.d
> pid$target::strlen:entry
> {
> trace (arg0);
> }
>
>
> $ date; dtrace -s strdup.d -c
> /tmp/sample; date
> Fri Sep 26 03:53:57 GMT 2014
> dtrace: script 'strdup.d' matched 1 probe
> calling strlen: 6
> calling strdup: foobar
> calling strlen: 6
> calling strdup: foobar
> calling strlen: 6
> calling strdup: foobar
> dtrace: pid 26100 has exited
> CPU ID FUNCTION:NAME
> 0 32060 strdup:return 34372624480
> 0 32060 strdup:return 34372624488
> 0 32060 strdup:return 34372624496
>
> Fri Sep 26 03:53:57 GMT 2014
> $ date ; dtrace -s strlen.d -c /tmp/sample
> ; date
> Fri Sep 26 03:54:04 GMT 2014
> dtrace: script 'strlen.d' matched 1 probe
> calling strlen: 6
> CPU ID FUNCTION:NAME
> 0 32060 strlen:entry 4196103
> ^C
>
> Fri Sep 26 03:56:42 GMT 2014
>
> Any help will be really appreciated. I am having dtrace related
> patches from firefox email chain < https://lists.freebsd.org/pipermail/freebsd-dtrace/2013-October/000107.html>.
>
> This is an enterprise application and we cannot move to 10.0
> release of freebsd at least for now
> Thank you.
> Madhava
> _______________________________________________
> freebsd-dtrace@freebsd.org mailing list
> https://lists.freebsd.org/mailman/listinfo/freebsd-dtrace
> To unsubscribe, send any mail to "freebsd-dtrace-unsubscribe@freebsd.org
"
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From: "George Neville-Neil" <gnn@neville-neil.com>
To: "Mark Johnston" <markj@FreeBSD.org>
Subject: Re: WITH_CTF vs -g
Date: Fri, 26 Sep 2014 17:52:24 +0300
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On 26 Sep 2014, at 1:51, Mark Johnston wrote:
> On Wed, Sep 10, 2014 at 08:23:21PM +0300, Andriy Gapon wrote:
>>
>> In my opinion WITH_CTF should imply -g in CFLAGS otherwise, as far as I can see,
>> there is nothing to generate CTF data from. Forcing an end-user to remember to
>> additionally pass -g is not nice.
>>
>> Also, I think that we can always have -g in CTFFLAGS, because the stripping step
>> takes care of the original DWARF data in any case. But I am not 100% sure about
>> this.
>>
>> What do you think?
>> Thanks!
>
> Hi Andriy,
>
> Are you planning to go through with this? I was just about to post this
> exact question, but then I remembered that you already have. :)
>
> FWIW, the diff I have in mind is below. It also removes some checks that
> I think are unnecessary from bsd.{lib,prog}.mk. It is not fully tested,
> but seems to work for me. I'm also not sure about unconditionally
> passing -g to ctfconvert and ctfmerge.
>
Mark,
Can you put this up in Phabricator? reviews.freebsd.org
Best,
George
> Thanks,
> -Mark
>
> diff --git a/share/mk/bsd.lib.mk b/share/mk/bsd.lib.mk
> index f0acf16..c6b689d 100644
> --- a/share/mk/bsd.lib.mk
> +++ b/share/mk/bsd.lib.mk
> @@ -36,7 +36,7 @@ NO_WERROR> .if defined(DEBUG_FLAGS)
> CFLAGS+= ${DEBUG_FLAGS}
>
> -.if ${MK_CTF} != "no" && ${DEBUG_FLAGS:M-g} != ""
> +.if ${MK_CTF} != "no"
> CTFFLAGS+= -g
> .endif
> .else
> diff --git a/share/mk/bsd.own.mk b/share/mk/bsd.own.mk
> index 486914b..32556a1 100644
> --- a/share/mk/bsd.own.mk
> +++ b/share/mk/bsd.own.mk
> @@ -128,6 +128,7 @@ __<bsd.own.mk>__:
>
> .if ${MK_CTF} != "no"
> CTFCONVERT_CMD= ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
> +DEBUG_FLAGS?= -g
> .elif defined(.PARSEDIR) || (defined(MAKE_VERSION) && ${MAKE_VERSION} >= 5201111300)
> CTFCONVERT_CMD> .else
> diff --git a/share/mk/bsd.prog.mk b/share/mk/bsd.prog.mk
> index 340950a..e4f7104 100644
> --- a/share/mk/bsd.prog.mk
> +++ b/share/mk/bsd.prog.mk
> @@ -20,7 +20,7 @@ NO_WERROR> CFLAGS+=${DEBUG_FLAGS}
> CXXFLAGS+=${DEBUG_FLAGS}
>
> -.if ${MK_CTF} != "no" && ${DEBUG_FLAGS:M-g} != ""
> +.if ${MK_CTF} != "no"
> CTFFLAGS+= -g
> .endif
> .endif
> _______________________________________________
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> https://lists.freebsd.org/mailman/listinfo/freebsd-dtrace
> To unsubscribe, send any mail to "freebsd-dtrace-unsubscribe@freebsd.org"
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