linux/arch
Oleg Nesterov 43918f2bf4 signals: remove 'handler' parameter to tracehook functions
Container-init must behave like global-init to processes within the
container and hence it must be immune to unhandled fatal signals from
within the container (i.e SIG_DFL signals that terminate the process).

But the same container-init must behave like a normal process to processes
in ancestor namespaces and so if it receives the same fatal signal from a
process in ancestor namespace, the signal must be processed.

Implementing these semantics requires that send_signal() determine pid
namespace of the sender but since signals can originate from workqueues/
interrupt-handlers, determining pid namespace of sender may not always be
possible or safe.

This patchset implements the design/simplified semantics suggested by
Oleg Nesterov.  The simplified semantics for container-init are:

	- container-init must never be terminated by a signal from a
	  descendant process.

	- container-init must never be immune to SIGKILL from an ancestor
	  namespace (so a process in parent namespace must always be able
	  to terminate a descendant container).

	- container-init may be immune to unhandled fatal signals (like
	  SIGUSR1) even if they are from ancestor namespace. SIGKILL/SIGSTOP
	  are the only reliable signals to a container-init from ancestor
	  namespace.

This patch:

Based on an earlier patch submitted by Oleg Nesterov and comments from
Roland McGrath (http://lkml.org/lkml/2008/11/19/258).

The handler parameter is currently unused in the tracehook functions.
Besides, the tracehook functions are called with siglock held, so the
functions can check the handler if they later need to.

Removing the parameter simiplifies changes to sig_ignored() in a follow-on
patch.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Daniel Lezcano <daniel.lezcano@free.fr>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:58 -07:00
..
alpha Simplify copy_thread() 2009-04-02 19:04:51 -07:00
arm Simplify copy_thread() 2009-04-02 19:04:51 -07:00
avr32 Simplify copy_thread() 2009-04-02 19:04:51 -07:00
blackfin Simplify copy_thread() 2009-04-02 19:04:51 -07:00
cris Simplify copy_thread() 2009-04-02 19:04:51 -07:00
frv Simplify copy_thread() 2009-04-02 19:04:51 -07:00
h8300 Simplify copy_thread() 2009-04-02 19:04:51 -07:00
ia64 Simplify copy_thread() 2009-04-02 19:04:51 -07:00
m32r Simplify copy_thread() 2009-04-02 19:04:51 -07:00
m68k Simplify copy_thread() 2009-04-02 19:04:51 -07:00
m68knommu Simplify copy_thread() 2009-04-02 19:04:51 -07:00
mips Simplify copy_thread() 2009-04-02 19:04:51 -07:00
mn10300 Simplify copy_thread() 2009-04-02 19:04:51 -07:00
parisc Simplify copy_thread() 2009-04-02 19:04:51 -07:00
powerpc Simplify copy_thread() 2009-04-02 19:04:51 -07:00
s390 Simplify copy_thread() 2009-04-02 19:04:51 -07:00
sh Simplify copy_thread() 2009-04-02 19:04:51 -07:00
sparc Simplify copy_thread() 2009-04-02 19:04:51 -07:00
um Simplify copy_thread() 2009-04-02 19:04:51 -07:00
x86 signals: remove 'handler' parameter to tracehook functions 2009-04-02 19:04:58 -07:00
xtensa Simplify copy_thread() 2009-04-02 19:04:51 -07:00
.gitignore
Kconfig dma-debug: add Kconfig entry 2009-03-05 14:36:50 +01:00