[bug fix] ECPG app crashes due to SIGBUS on SPARC Solaris

Started by MauMauabout 12 years ago8 messages

maumau307@gmail.com

about 12 years ago

1 attachment(s)

Hello,

I encountered a bug of ECPG with PG 9.2.4, which probably exists in all
releases. The attached patch is for 9.4. Could you review and backport
this to at least 9.2 and later?

[Problem]
The attached ECPG app crashes and dumps core with SIGBUS on Solaris for
SPARC. I used Solaris 10, and Oracle Studio to compile the app for 64-bit
build. The same app completes successfully on Linux and Windows for
x86/x564.

The steps to reproduce the problem is:
1. ecpg sigbus.pgc
2. cc -xtarget=generic64 -I<pgsql_dir>/include
sigbus.c -L<pgsql_dir>/lib -lecpg
3. a.out

When execting FETCH statement using an SQL descriptor, the app crashes at
the following line in ECPGdo(), which is in
src/interfaces/ecpg/ecpglib/execute.c:

var->value = *((char **) (var->pointer));

[Cause]
ecpg outputs the following line in the preprocessed source file:

{ ECPGdo(__LINE__, 0, 1, NULL, 0, ECPGst_normal, "fetch $0",
ECPGt_char,(cur),(long)4,(long)1,(4)*sizeof(char),
ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L, ECPGt_EOIT,
ECPGt_descriptor, (desc1), 0L, 0L, 0L,
ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L, ECPGt_EORT);}

So, the above line is executed in ECPGdo(). On the other hand, desc1 is not
aligned on 8-byte boundary. This unaligned access causes SIGBUS.

[Fix]
Because desc1 is a char array, else block should be executed instead of the
above path.

var->value = var->pointer;

Therefore, make ecpg pass SQL descriptor host variables to ECPGdo() with
non-zero lengths.

Regards
MauMau

Attachments:

ECPG_descriptor_crash.patchapplication/octet-stream; name=ECPG_descriptor_crash.patchDownload

diff -rpcd a/src/interfaces/ecpg/preproc/type.c b/src/interfaces/ecpg/preproc/type.c
*** a/src/interfaces/ecpg/preproc/type.c	2013-12-02 09:17:05.000000000 +0900
--- b/src/interfaces/ecpg/preproc/type.c	2013-12-24 13:09:07.000000000 +0900
*************** ECPGdump_a_simple(FILE *o, const char *n
*** 368,374 ****
  		fprintf(o, "\n\tECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L, ");
  	else if (type == ECPGt_descriptor)
  		/* remember that name here already contains quotes (if needed) */
! 		fprintf(o, "\n\tECPGt_descriptor, %s, 0L, 0L, 0L, ", name);
  	else if (type == ECPGt_sqlda)
  		fprintf(o, "\n\tECPGt_sqlda, &%s, 0L, 0L, 0L, ", name);
  	else
--- 368,374 ----
  		fprintf(o, "\n\tECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L, ");
  	else if (type == ECPGt_descriptor)
  		/* remember that name here already contains quotes (if needed) */
! 		fprintf(o, "\n\tECPGt_descriptor, %s, 1, %s, 1, ", name, arrsize);
  	else if (type == ECPGt_sqlda)
  		fprintf(o, "\n\tECPGt_sqlda, &%s, 0L, 0L, 0L, ", name);
  	else

Boszormenyi Zoltan

zb@cybertec.at

about 12 years ago

In reply to: MauMau (#1)

Re: [bug fix] ECPG app crashes due to SIGBUS on SPARC Solaris

2013-12-24 13:55 kelteze'ssel, MauMau i'rta:

Hello,

I encountered a bug of ECPG with PG 9.2.4, which probably exists in all releases. The
attached patch is for 9.4. Could you review and backport this to at least 9.2 and later?

[Problem]
The attached ECPG app

The app wasn't attached, only the patch.
If this is a small test app, it can also be a part of the patch in the form of a
regression test.

crashes and dumps core with SIGBUS on Solaris for SPARC. I used Solaris 10, and Oracle
Studio to compile the app for 64-bit build. The same app completes successfully on Linux
and Windows for x86/x564.

The steps to reproduce the problem is:
1. ecpg sigbus.pgc
2. cc -xtarget=generic64 -I<pgsql_dir>/include sigbus.c -L<pgsql_dir>/lib -lecpg
3. a.out

When execting FETCH statement using an SQL descriptor, the app crashes at the following
line in ECPGdo(), which is in src/interfaces/ecpg/ecpglib/execute.c:

var->value = *((char **) (var->pointer));

[Cause]
ecpg outputs the following line in the preprocessed source file:

{ ECPGdo(__LINE__, 0, 1, NULL, 0, ECPGst_normal, "fetch $0",
ECPGt_char,(cur),(long)4,(long)1,(4)*sizeof(char),
ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L, ECPGt_EOIT,
ECPGt_descriptor, (desc1), 0L, 0L, 0L,
ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L, ECPGt_EORT);}

So, the above line is executed in ECPGdo(). On the other hand, desc1 is not aligned on
8-byte boundary. This unaligned access causes SIGBUS.

[Fix]
Because desc1 is a char array, else block should be executed instead of the above path.

var->value = var->pointer;

Therefore, make ecpg pass SQL descriptor host variables to ECPGdo() with non-zero lengths.

Regards
MauMau

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http://www.postgresql.at/

MauMau

maumau307@gmail.com

about 12 years ago

In reply to: Boszormenyi Zoltan (#2)

1 attachment(s)

Re: [bug fix] ECPG app crashes due to SIGBUS on SPARC Solaris

From: "Boszormenyi Zoltan" <zb@cybertec.at>

The app wasn't attached, only the patch.
If this is a small test app, it can also be a part of the patch in the
form of a
regression test.

Sorry, attached. Thank you for pointing it out.

Regards
MauMau

Michael Meskes

meskes@postgresql.org

about 12 years ago

In reply to: MauMau (#1)

Re: [bug fix] ECPG app crashes due to SIGBUS on SPARC Solaris

On Tue, Dec 24, 2013 at 09:55:45PM +0900, MauMau wrote:

The attached ECPG app crashes and dumps core with SIGBUS on Solaris
for SPARC. I used Solaris 10, and Oracle Studio to compile the app
for 64-bit build. The same app completes successfully on Linux and
Windows for x86/x564.

What happens to the regression test suite on your system? There are test cases
that access a descriptor in a similar way I think.

Because desc1 is a char array, else block should be executed instead
of the above path.

Therefore, make ecpg pass SQL descriptor host variables to ECPGdo()
with non-zero lengths.

How did you decide which values to put in? I fail to see a reason for choosing
exactly these values.

Mkichael
--
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Michael at Fam-Meskes dot De, Michael at Meskes dot (De|Com|Net|Org)
Michael at BorussiaFan dot De, Meskes at (Debian|Postgresql) dot Org
Jabber: michael.meskes at gmail dot com
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MauMau

maumau307@gmail.com

about 12 years ago

In reply to: Michael Meskes (#4)

Re: [bug fix] ECPG app crashes due to SIGBUS on SPARC Solaris

From: "Michael Meskes" <meskes@postgresql.org>

What happens to the regression test suite on your system? There are test
cases
that access a descriptor in a similar way I think.

OK, I'll run the ECPG regression test on Solaris without the patch. Please
wait until Jan 6 2014 or so, because we've just entered new year holidays
here in Japan.

How did you decide which values to put in? I fail to see a reason for
choosing
exactly these values.

Yes, the value is arbitrary except it should be non-zero so that ECPGdo()
can execute the else block. And the lengths here are irrelevant to the
actual processing. I thought the original 0 was chosen arbitrarily and I
could do so too. If I can do better, please let me know that.

Regards
MauMau

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Michael Meskes

meskes@postgresql.org

about 12 years ago

In reply to: MauMau (#5)

Re: [bug fix] ECPG app crashes due to SIGBUS on SPARC Solaris

On Sat, Dec 28, 2013 at 08:04:09AM +0900, MauMau wrote:

OK, I'll run the ECPG regression test on Solaris without the patch.
Please wait until Jan 6 2014 or so, because we've just entered new
year holidays here in Japan.

Sure, we're no in a particular hurry.

Michael
--
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Michael at Fam-Meskes dot De, Michael at Meskes dot (De|Com|Net|Org)
Michael at BorussiaFan dot De, Meskes at (Debian|Postgresql) dot Org
Jabber: michael.meskes at gmail dot com
VfL Borussia! Força Barça! Go SF 49ers! Use Debian GNU/Linux, PostgreSQL

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MauMau

maumau307@gmail.com

about 12 years ago

In reply to: Michael Meskes (#6)

Re: [bug fix] ECPG app crashes due to SIGBUS on SPARC Solaris

From: "Michael Meskes" <meskes@postgresql.org>

On Sat, Dec 28, 2013 at 08:04:09AM +0900, MauMau wrote:

OK, I'll run the ECPG regression test on Solaris without the patch.
Please wait until Jan 6 2014 or so, because we've just entered new
year holidays here in Japan.

Sure, we're no in a particular hurry.

I ran the ECPG regression test with the unpatched 64-bit PostgreSQL 9.2.4 on
SPARC Solaris, and it succeeded (all 54 tests passed). For information, I
did as follows:

configure --prefix=... CC='<Oracle_Studio_HOME>/bin/cc -xtarget=generic64'
...
gmake
gmake install
initdb -E UTF8 --no-locale
pg_ctl start
cd postgresql-9.2.4/src/interfaces/ecpg
gmake check

I guess that's that's because the regression test doesn't have a test case
which specifies SQL descriptor name with a host variable.

Regards
MauMau

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Michael Meskes

meskes@postgresql.org

about 12 years ago

In reply to: MauMau (#7)

Re: [bug fix] ECPG app crashes due to SIGBUS on SPARC Solaris

On Sun, Jan 05, 2014 at 03:42:42PM +0900, MauMau wrote:

I ran the ECPG regression test with the unpatched 64-bit PostgreSQL
9.2.4 on SPARC Solaris, and it succeeded (all 54 tests passed). For
...

Thanks a lot. Patch applied to HEAD and all the backbranches. Will push shortly.

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