From: Eric W. Biederman ebiederm@xmission.com
[ Upstream commit e7f7c99ba911f56bc338845c1cd72954ba591707 ]
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 keescook@chromium.org Link: https://lkml.kernel.org/r/875yssekcd.fsf_-_@email.froward.int.ebiederm.org Signed-off-by: "Eric W. Biederman" ebiederm@xmission.com Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/signal.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/kernel/signal.c b/kernel/signal.c index aea93d6a5520a..6e3dbb3d12170 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2710,19 +2710,19 @@ 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;