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signal/bpfilter: Fix bpfilter_kernl to use send_sig not force_sig

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[ 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>
This commit is contained in:
Eric W. Biederman 2019-05-15 12:23:03 -05:00 committed by Greg Kroah-Hartman
parent f771e86b02
commit 5d1b927a65
1 changed files with 1 additions and 1 deletions
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2
net/bpfilter/bpfilter_kern.c
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@ -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);