[REVIEW,05/26] signal/bpfilter: Fix bpfilter_kernl to use send_sig not force_sig

Submitted by Eric W. Biederman on May 23, 2019, 12:38 a.m.


Message ID 20190523003916.20726-6-ebiederm@xmission.com
State New
Series "signal: Remove task argument from force_sig_info"
Headers show

Commit Message

Eric W. Biederman May 23, 2019, 12:38 a.m.
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

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>
 net/bpfilter/bpfilter_kern.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

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diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
index 7ee4fea93637..c0f0990f30b6 100644
--- a/net/bpfilter/bpfilter_kern.c
+++ b/net/bpfilter/bpfilter_kern.c
@@ -22,7 +22,7 @@  static void shutdown_umh(void)
 	tsk = get_pid_task(find_vpid(bpfilter_ops.info.pid), PIDTYPE_PID);
 	if (tsk) {
-		force_sig(SIGKILL, tsk);
+		send_sig(SIGKILL, tsk, 1);