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Revision 10f1d5d111e8aed46a0f1179faf9a3cf422f689e authored by Joe Thornber on 27 June 2014, 19:29:04 UTC, committed by Mike Snitzer on 10 July 2014, 20:44:14 UTC 
dm io: fix a race condition in the wake up code for sync_io
 
There's a race condition between the atomic_dec_and_test(&io->count)
in dec_count() and the waking of the sync_io() thread.  If the thread
is spuriously woken immediately after the decrement it may exit,
making the on stack io struct invalid, yet the dec_count could still
be using it.

Fix this race by using a completion in sync_io() and dec_count().

Reported-by: Minfei Huang <huangminfei@ucloud.cn>
Signed-off-by: Joe Thornber <thornber@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
1 parent bf14299
Raw File
gcc-version.sh 
#!/bin/sh
#
# gcc-version [-p] gcc-command
#
# Prints the gcc version of `gcc-command' in a canonical 4-digit form
# such as `0295' for gcc-2.95, `0303' for gcc-3.3, etc.
#
# With the -p option, prints the patchlevel as well, for example `029503' for
# gcc-2.95.3, `030301' for gcc-3.3.1, etc.
#

if [ "$1" = "-p" ] ; then
	with_patchlevel=1;
	shift;
fi

compiler="$*"

if [ ${#compiler} -eq 0 ]; then
	echo "Error: No compiler specified."
	printf "Usage:\n\t$0 <gcc-command>\n"
	exit 1
fi

MAJOR=$(echo __GNUC__ | $compiler -E -x c - | tail -n 1)
MINOR=$(echo __GNUC_MINOR__ | $compiler -E -x c - | tail -n 1)
if [ "x$with_patchlevel" != "x" ] ; then
	PATCHLEVEL=$(echo __GNUC_PATCHLEVEL__ | $compiler -E -x c - | tail -n 1)
	printf "%02d%02d%02d\\n" $MAJOR $MINOR $PATCHLEVEL
else
	printf "%02d%02d\\n" $MAJOR $MINOR
fi
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