[PATCH 1/1] Fix segfault in DTC

On 25/09/2012 16:30, David Gibson wrote:

On Tue, Sep 25, 2012 at 10:58:09AM -0700, Markus Mayer wrote:

quoted

Prior to this change, an empty input file would cause a segfault, because
yylloc had never been initialized. There was never any characters for the
lexer to match, so YY_USER_ACTION was never executed before the parse error
was detected.

When the parser printed the error message, it tried to include the name of
the file, but the structure holding the file name (yylloc.file, referenced
as pos->file) had never been initialized.

Without the fix:

$ ./dtc /dev/null
DTC: dts->dts  on file "/dev/null"
Segmentation fault (core dumped)

$ gdb dtc core
Program terminated with signal 11, Segmentation fault.
     at scripts/dtc/srcpos.c:194
194			fname = pos->file->name;
(gdb) bt
     at scripts/dtc/srcpos.c:194
     fmt=0x40d769 "%s", va=0x7fffbf027148) at scripts/dtc/srcpos.c:220
     at scripts/dtc/dtc-parser.tab.c:1920
     at scripts/dtc/treesource.c:38
     at scripts/dtc/dtc.c:203
(gdb) p *pos
$1 = {first_line = 0, first_column = 0, last_line = 0, last_column = 0,
   file = 0x0}

Which dtc version did you observe this with?  I'm unable to reproduce
the SEGV with current git.

That was

$ cat version_gen.h
#define DTC_VERSION "DTC 1.2.0-g37c0b6a0"

from git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git. 
In other words, the DTC used by the Linux 3.6-rc series.

Regards,
-Markus