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author | John Sperbeck <jsperbeck@google.com> | 2023-05-21 22:29:53 +0300 |
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committer | Tejun Heo <tj@kernel.org> | 2023-05-23 02:59:37 +0300 |
commit | 2bd110339288c18823dcace602b63b0d8627e520 (patch) | |
tree | edbebd30f566d2b054e1448372f6b9702919336f /Documentation | |
parent | ab1de7ead871ebe6d12a774c3c25de0388cde082 (diff) | |
download | linux-2bd110339288c18823dcace602b63b0d8627e520.tar.xz |
cgroup: always put cset in cgroup_css_set_put_fork
A successful call to cgroup_css_set_fork() will always have taken
a ref on kargs->cset (regardless of CLONE_INTO_CGROUP), so always
do a corresponding put in cgroup_css_set_put_fork().
Without this, a cset and its contained css structures will be
leaked for some fork failures. The following script reproduces
the leak for a fork failure due to exceeding pids.max in the
pids controller. A similar thing can happen if we jump to the
bad_fork_cancel_cgroup label in copy_process().
[ -z "$1" ] && echo "Usage $0 pids-root" && exit 1
PID_ROOT=$1
CGROUP=$PID_ROOT/foo
[ -e $CGROUP ] && rmdir -f $CGROUP
mkdir $CGROUP
echo 5 > $CGROUP/pids.max
echo $$ > $CGROUP/cgroup.procs
fork_bomb()
{
set -e
for i in $(seq 10); do
/bin/sleep 3600 &
done
}
(fork_bomb) &
wait
echo $$ > $PID_ROOT/cgroup.procs
kill $(cat $CGROUP/cgroup.procs)
rmdir $CGROUP
Fixes: ef2c41cf38a7 ("clone3: allow spawning processes into cgroups")
Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: John Sperbeck <jsperbeck@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'Documentation')
0 files changed, 0 insertions, 0 deletions