From: "Eric W. Biederman" ebiederm@xmission.com
[ Upstream commit f9070dc94542093fd516ae4ccea17ef46a4362c5 ]
The locking in force_sig_info is not prepared to deal with a task that exits or execs (as sighand may change). The is not a locking problem in force_sig 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 confusing and 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: Daniel Lezcano daniel.lezcano@free.fr Cc: Serge Hallyn serge@hallyn.com Cc: Oleg Nesterov oleg@redhat.com Fixes: cf3f89214ef6 ("pidns: add reboot_pid_ns() to handle the reboot syscall") Signed-off-by: "Eric W. Biederman" ebiederm@xmission.com Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/pid_namespace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index 4918314893bc..22091c88b3bb 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -351,7 +351,7 @@ int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd) }
read_lock(&tasklist_lock); - force_sig(SIGKILL, pid_ns->child_reaper); + send_sig(SIGKILL, pid_ns->child_reaper, 1); read_unlock(&tasklist_lock);
do_exit(0);