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Subject[kbuild] drivers/accessibility/speakup/speakup_audptr.c:138:20: warning: Array index 'test' is used before limits check.
tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git  master
head: 76c057c84d286140c6c416c3b4ba832cd1d8984e
commit: 2067fd92d75b6d9085a43caf050bca5d88c491b8 staging/speakup: Move out of staging
compiler: ia64-linux-gcc (GCC) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

cppcheck possible warnings: (new ones prefixed by >>, may not real problems)

>> drivers/accessibility/speakup/speakup_audptr.c:138:20: warning: Array index 'test' is used before limits check. [arrayIndexThenCheck]
} while (synth_id[test] != 'n' && test < 32);
^

vim +/test +138 drivers/accessibility/speakup/speakup_audptr.c

c6e3fd22cd5383 drivers/staging/speakup/speakup_audptr.c William Hubbs 2010-10-07 127 static void synth_version(struct spk_synth *synth)
c6e3fd22cd5383 drivers/staging/speakup/speakup_audptr.c William Hubbs 2010-10-07 128 {
c6e3fd22cd5383 drivers/staging/speakup/speakup_audptr.c William Hubbs 2010-10-07 129 unsigned char test = 0;

"test" is a weird name for an index, and the type should be int.

c6e3fd22cd5383 drivers/staging/speakup/speakup_audptr.c William Hubbs 2010-10-07 130 char synth_id[40] = "";
^^^^^^^^^^^^^^^^^^^^^^^

8e69a811068657 drivers/staging/speakup/speakup_audptr.c Domagoj Trsan 2014-09-09 131
98c1fda752b604 drivers/staging/speakup/speakup_audptr.c Okash Khawaja 2017-03-16 132 synth->synth_immediate(synth, "\x05[Q]");
ca693dcd5c0264 drivers/staging/speakup/speakup_audptr.c Okash Khawaja 2017-04-29 133 synth_id[test] = synth->io_ops->synth_in();
c6e3fd22cd5383 drivers/staging/speakup/speakup_audptr.c William Hubbs 2010-10-07 134 if (synth_id[test] == 'A') {
c6e3fd22cd5383 drivers/staging/speakup/speakup_audptr.c William Hubbs 2010-10-07 135 do {
c6e3fd22cd5383 drivers/staging/speakup/speakup_audptr.c William Hubbs 2010-10-07 136 /* read version string from synth */
ca693dcd5c0264 drivers/staging/speakup/speakup_audptr.c Okash Khawaja 2017-04-29 137 synth_id[++test] = synth->io_ops->synth_in();
c6e3fd22cd5383 drivers/staging/speakup/speakup_audptr.c William Hubbs 2010-10-07 @138 } while (synth_id[test] != '\n' && test < 32);
^^^^^^^^^
This is a limit check but it's 32 instead of 40 so the array can't
actually overflow.

c6e3fd22cd5383 drivers/staging/speakup/speakup_audptr.c William Hubbs 2010-10-07 139 synth_id[++test] = 0x00;
c6e3fd22cd5383 drivers/staging/speakup/speakup_audptr.c William Hubbs 2010-10-07 140 }
c6e3fd22cd5383 drivers/staging/speakup/speakup_audptr.c William Hubbs 2010-10-07 141 if (synth_id[0] == 'A')
c6e3fd22cd5383 drivers/staging/speakup/speakup_audptr.c William Hubbs 2010-10-07 142 pr_info("%s version: %s", synth->long_name, synth_id);
c6e3fd22cd5383 drivers/staging/speakup/speakup_audptr.c William Hubbs 2010-10-07 143 }


This if statement could be merge together with the previous one. Also
we could reverse the previous if statement:

synth_id[0] = synth->io_ops->synth_in();
if (synth_id[0] != 'A')
return;

for (i = 1; i < sizeof(synth_id) - 1; i++) {
/* read version string from synth */
synth_id[i] = synth->io_ops->synth_in();
if (synth_id[i] == '\n')
break;
}
synth_id[i] = '\0';
pr_info("%s version: %s", synth->long_name, synth_id);
}

---
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