kernel/exit.c: if init dies, log a signal which killed it, if any
authorDenys Vlasenko <vda.linux@googlemail.com>
Fri, 23 Mar 2012 22:01:54 +0000 (15:01 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 23 Mar 2012 23:58:32 +0000 (16:58 -0700)
commit397a21f24d455982a8a6f9bc11b5f3326ce3c6ef
treeba92e73491599341db615f719df97cea6fdfaf6b
parentebec18a6d3aa1e7d84aab16225e87fd25170ec2b
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 <vda.linux@googlemail.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>
kernel/exit.c