torture: Check for nul bytes in console output

When starting a new torture run while an old one is still running, both
qemu processes can be outputting to the same console.out file.  This can
cause quite a bit of confusion, so this commit checks for this situation,
which is normally indicated by nul bytes in the console output.  Yes,
if your new run uses up an exact number of blocks of the file, this
check will be ineffective, but the odds are not bad.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>

diff --git a/tools/testing/selftests/rcutorture/bin/parse-console.sh b/tools/testing/selftests/rcutorture/bin/parse-console.sh
index a0bde6c7945620663713a49d2f28c3ea9f966361..f962ba4cf68b6a06121b1d6f2c11ce8ed8df63ee 100755 (executable)
--- a/tools/testing/selftests/rcutorture/bin/parse-console.sh
+++ b/tools/testing/selftests/rcutorture/bin/parse-console.sh
@@ -32,6 +32,10 @@ title="$2"
 
 . functions.sh
 
+if grep -Pq '\x00' < $file
+then
+       print_warning Console output contains nul bytes, old qemu still running?
+fi
 egrep 'Badness|WARNING:|Warn|BUG|===========|Call Trace:|Oops:' < $file | grep -v 'ODEBUG: ' | grep -v 'Warning: unable to open an initial console' > $T
 if test -s $T
 then