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authorJamie Iles <jamie.iles@oracle.com>2017-08-18 15:16:18 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-08-18 15:32:02 -0700
commiteb61b5911bdc923875cde99eb25203a0e2b06d43 (patch)
tree5ba019b857b23212a0c30aeb24f7a3f54b568b51
parent6b31d5955cb29a51c5baffee382f213d75e98fb8 (diff)
downloadlinux-eb61b5911bdc923875cde99eb25203a0e2b06d43.tar.bz2
signal: don't remove SIGNAL_UNKILLABLE for traced tasks.
When forcing a signal, SIGNAL_UNKILLABLE is removed to prevent recursive faults, but this is undesirable when tracing. For example, debugging an init process (whether global or namespace), hitting a breakpoint and SIGTRAP will force SIGTRAP and then remove SIGNAL_UNKILLABLE. Everything continues fine, but then once debugging has finished, the init process is left killable which is unlikely what the user expects, resulting in either an accidentally killed init or an init that stops reaping zombies. Link: http://lkml.kernel.org/r/20170815112806.10728-1-jamie.iles@oracle.com Signed-off-by: Jamie Iles <jamie.iles@oracle.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/signal.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 7e33f8c583e6..ed804a470dcd 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1194,7 +1194,11 @@ force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
recalc_sigpending_and_wake(t);
}
}
- if (action->sa.sa_handler == SIG_DFL)
+ /*
+ * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
+ * debugging to leave init killable.
+ */
+ if (action->sa.sa_handler == SIG_DFL && !t->ptrace)
t->signal->flags &= ~SIGNAL_UNKILLABLE;
ret = specific_send_sig_info(sig, info, t);
spin_unlock_irqrestore(&t->sighand->siglock, flags);