From e7f7c99ba911f56bc338845c1cd72954ba591707 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Mon, 15 Nov 2021 11:55:57 -0600 Subject: [PATCH] signal: In get_signal test for signal_group_exit every time through the loop Recently while investigating a problem with rr and signals I noticed that siglock is dropped in ptrace_signal and get_signal does not jump to relock. Looking farther to see if the problem is anywhere else I see that do_signal_stop also returns if signal_group_exit is true. I believe that test can now never be true, but it is a bit hard to trace through and be certain. Testing signal_group_exit is not expensive, so move the test for signal_group_exit into the for loop inside of get_signal to ensure the test is never skipped improperly. This has been a potential problem since I added the test for signal_group_exit was added. Fixes: 35634ffa1751 ("signal: Always notice exiting tasks") Reviewed-by: Kees Cook Link: https://lkml.kernel.org/r/875yssekcd.fsf_-_@email.froward.int.ebiederm.org Signed-off-by: "Eric W. Biederman" --- kernel/signal.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index 7c4b7ae714d4..986fa69c15c5 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2662,19 +2662,19 @@ bool get_signal(struct ksignal *ksig) goto relock; } - /* Has this task already been marked for death? */ - if (signal_group_exit(signal)) { - ksig->info.si_signo = signr = SIGKILL; - sigdelset(¤t->pending.signal, SIGKILL); - trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO, - &sighand->action[SIGKILL - 1]); - recalc_sigpending(); - goto fatal; - } - for (;;) { struct k_sigaction *ka; + /* Has this task already been marked for death? */ + if (signal_group_exit(signal)) { + ksig->info.si_signo = signr = SIGKILL; + sigdelset(¤t->pending.signal, SIGKILL); + trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO, + &sighand->action[SIGKILL - 1]); + recalc_sigpending(); + goto fatal; + } + if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) && do_signal_stop(0)) goto relock; -- GitLab