[PATCH 12/17] signal: Compute the process exit_code in get_signal

Eric W. Biederman
2022-01-03T21:34:19Z

In prepartion for moving the work of sys_exit and sys_group_exit into
get_signal compute exit_code in get_signal, make PF_SIGNALED depend on
the exit_code and pass the exit_code to do_group_exit.

Anytime there is a group exit the exit_code may differ from the signal
number.

To match the historical precedent as best I can make the exit_code 0
during exec. (The exit_code field would not have been set but probably
would have been left at a value of 0).

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
kernel/signal.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index fd3c404de8b6..2a24cca00ca1 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2707,6 +2707,7 @@ bool get_signal(struct ksignal *ksig)
for (;;) {
struct k_sigaction *ka;
enum pid_type type;
+ int exit_code;

/* Has this task already been marked for death? */
if ((signal->flags & SIGNAL_GROUP_EXIT) ||
@@ -2716,6 +2717,10 @@ bool get_signal(struct ksignal *ksig)
trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
&sighand->action[SIGKILL - 1]);
recalc_sigpending();
+ if (signal->flags & SIGNAL_GROUP_EXIT)
+ exit_code = signal->group_exit_code;
+ else
+ exit_code = 0;
goto fatal;
}

@@ -2837,15 +2842,17 @@ bool get_signal(struct ksignal *ksig)
continue;
}

+ /*
+ * Anything else is fatal, maybe with a core dump.
+ */
+ exit_code = signr;
fatal:
spin_unlock_irq(&sighand->siglock);
if (unlikely(cgroup_task_frozen(current)))
cgroup_leave_frozen(true);

- /*
- * Anything else is fatal, maybe with a core dump.
- */
- current->flags |= PF_SIGNALED;
+ if (exit_code & 0x7f)
+ current->flags |= PF_SIGNALED;

if (sig_kernel_coredump(signr)) {
if (print_fatal_signals)
@@ -2873,7 +2880,7 @@ bool get_signal(struct ksignal *ksig)
/*
* Death signals, no core dump.
*/
- do_group_exit(ksig->info.si_signo);
+ do_group_exit(exit_code);
/* NOTREACHED */
}
spin_unlock_irq(&sighand->siglock);
--
2.29.2