[mdb-discuss] mdb :r command corrupts arguments for 64 bit x86 debug target
Kuriakose Kuruvilla wrote: Hi J?rgen This is because of the strncpy() in string_unquote() at mdb_lex.1:699 http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/cmd/mdb/common/mdb/mdb_lex.l#699. The source and destination overlap but the manpage for strncpy.3c says... If copying takes place between objects that overlap, the behavior of strcpy(), strncpy(), and strlcpy() is undefined. Sounds like issues with the recent amd64 optimization of strcpy that were discussed a few weeks ago in opensolaris-code, including CR 6914012. See the amd64 strcpy() on SXCE NV 129 vs. POSIX.1-2008 thread on http://mail.opensolaris.org/pipermail/opensolaris-code/2009-December/thread.html and http://mail.opensolaris.org/pipermail/opensolaris-code/2010-January/thread.html -- -Alan Coopersmith- alan.coopersmith at sun.com Sun Microsystems, Inc. - X Window System Engineering
[mdb-discuss] mdb :r command corrupts arguments for 64 bit x86 debug target
Can anyone reproduce this:
I'm running SX:CE b129 amd64, bfu'ed to current ON bits;
the same problem exists on OpenSolaris dev build b132.
I'm trying to debug a /usr/sbin/amd64/update_drv problem,
using mdb. Problem is that the debug target somehow
receives a :r quoted string argument slightly modified.
Here's an example that reproduces the issue with
a 64-bit echo test program:
% cat x.c
#include stdio.h
int
main(int argc, char **argv)
{
int i;
for (i = 1; argv[i] != NULL; i++)
printf(%s , argv[i]);
printf(\n);
return 0;
}
% cc -m64 -o x x.c
% ./x -d -i 'pci1814,601' rtls
-d -i pci1814,601 rtls
Ok, test program works as expected.
Now the same under mdb control:
% mdb ./x
:r -d -i 'pci1814,601' rtls
-d -i pci1144,601 rtls
mdb: target has terminated
Note how the pci1814,601 string
argument was modified when running
under mdb.
The problem does not happen with a
32-bit debug target.
--
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