From 397a21f24d455982a8a6f9bc11b5f3326ce3c6ef Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Fri, 23 Mar 2012 15:01:54 -0700 Subject: [PATCH] kernel/exit.c: if init dies, log a signal which killed it, if any I just received another user's pleas for help when their init mysteriously died. I again explained that they need to check whether it died because of bad instruction, a segv, or something else. Which was an annoying detour into writing a trivial C program to spawn his init and print its exit code: http://lists.busybox.net/pipermail/busybox/2012-January/077172.html I hear you saying "just test it under /bin/sh". Well, the crashing init _was_ /bin/sh. Which prompted me to make kernel do this first step automatically. We can print exit code, which makes it possible to see that death was from e.g. SIGILL without writing test programs. [akpm@linux-foundation.org: add 0x to hex number output] Signed-off-by: Denys Vlasenko Acked-by: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/exit.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/kernel/exit.c b/kernel/exit.c index 456329fd4ea3..3db1909faed9 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -711,8 +711,11 @@ static struct task_struct *find_new_reaper(struct task_struct *father) if (unlikely(pid_ns->child_reaper == father)) { write_unlock_irq(&tasklist_lock); - if (unlikely(pid_ns == &init_pid_ns)) - panic("Attempted to kill init!"); + if (unlikely(pid_ns == &init_pid_ns)) { + panic("Attempted to kill init! exitcode=0x%08x\n", + father->signal->group_exit_code ?: + father->exit_code); + } zap_pid_ns_processes(pid_ns); write_lock_irq(&tasklist_lock); -- 2.20.1