From: "Eric W. Biederman" ebiederm@xmission.com
[ Upstream commit 1dfd1711de2952fd1bfeea7152bd1687a4eea771 ]
The locking in force_sig_info is not prepared to deal with a task that exits or execs (as sighand may change). As force_sig is only built to handle synchronous exceptions.
Further the function force_sig_info changes the signal state if the signal is ignored, or blocked or if SIGNAL_UNKILLABLE will prevent the delivery of the signal. The signal SIGKILL can not be ignored and can not be blocked and SIGNAL_UNKILLABLE won't prevent it from being delivered.
So using force_sig rather than send_sig for SIGKILL is pointless.
Because it won't impact the sending of the signal and and because using force_sig is wrong, replace force_sig with send_sig.
Cc: Alexei Starovoitov ast@kernel.org Cc: David S. Miller davem@davemloft.net Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module") Signed-off-by: "Eric W. Biederman" ebiederm@xmission.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- net/bpfilter/bpfilter_kern.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c index 94e88f5..450b257 100644 --- a/net/bpfilter/bpfilter_kern.c +++ b/net/bpfilter/bpfilter_kern.c @@ -25,7 +25,7 @@ static void shutdown_umh(struct umh_info *info) return; tsk = get_pid_task(find_vpid(info->pid), PIDTYPE_PID); if (tsk) { - force_sig(SIGKILL, tsk); + send_sig(SIGKILL, tsk, 1); put_task_struct(tsk); } fput(info->pipe_to_umh);