Subject: [PATCH 4/5] Define is_global_init() and is_container_init().
From: Serge E. Hallyn <serue@us.ibm.com>
is_init() is an ambiguous name for the pid==1 check. Split it into
is_global_init() and is_container_init().
A container init has it's tsk->pid == 1.
A global init also has it's tsk->pid == 1 and it's active pid namespace
is the init_pid_ns. But rather than check the active pid namespace,
compare the task structure with 'init_pid_ns.child_reaper', which is
initialized during boot to the /sbin/init process and never changes.
Changelog:
2.6.22-rc4-mm2-pidns1:
- Use 'init_pid_ns.child_reaper' to determine if a given task is the
global init (/sbin/init) process. This would improve performance
and remove dependence on the task_pid().
2.6.21-mm2-pidns2:
- [Sukadev Bhattiprolu] Changed is_container_init() calls in {powerpc,
ppc,avr32}/traps.c for the _exception() call to is_global_init().
This way, we kill only the container if the container's init has a
bug rather than force a kernel panic.
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Acked-by: Pavel Emelianov <xemul@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Herbert Poetzel <herbert@13thfloor.at>
---
arch/alpha/mm/fault.c | 2 +-
arch/arm/mm/fault.c | 2 +-
arch/arm26/mm/fault.c | 2 +-
arch/avr32/kernel/traps.c | 2 +-
arch/avr32/mm/fault.c | 6 +++---
arch/i386/lib/usercopy.c | 2 +-
arch/i386/mm/fault.c | 2 +-
arch/ia64/mm/fault.c | 2 +-
arch/m68k/mm/fault.c | 2 +-
arch/mips/mm/fault.c | 2 +-
arch/powerpc/kernel/traps.c | 2 +-
arch/powerpc/mm/fault.c | 2 +-
arch/powerpc/platforms/pseries/ras.c | 2 +-
arch/ppc/kernel/traps.c | 2 +-
arch/ppc/mm/fault.c | 2 +-
arch/s390/lib/uaccess_pt.c | 2 +-
arch/s390/mm/fault.c | 2 +-
arch/sh/mm/fault.c | 2 +-
arch/sh64/mm/fault.c | 6 +++---
arch/um/kernel/trap.c | 2 +-
arch/x86_64/mm/fault.c | 2 +-
arch/xtensa/mm/fault.c | 2 +-
drivers/char/sysrq.c | 2 +-
include/linux/sched.h | 12 ++++++++++--
kernel/capability.c | 3 ++-
kernel/exit.c | 2 +-
kernel/kexec.c | 2 +-
kernel/pid.c | 7 +++++++
kernel/signal.c | 2 +-
kernel/sysctl.c | 2 +-
mm/oom_kill.c | 4 ++--
security/commoncap.c | 3 ++-
32 files changed, 54 insertions(+), 37 deletions(-)
Index: lx26-22-rc6-mm1a/include/linux/sched.h
===================================================================
--- lx26-22-rc6-mm1a.orig/include/linux/sched.h 2007-07-16 12:55:15.000000000 -0700
+++ lx26-22-rc6-mm1a/include/linux/sched.h 2007-07-16 13:10:48.000000000 -0700
@@ -1219,12 +1219,20 @@ static inline int pid_alive(struct task_
}
/**
- * is_init - check if a task structure is init
+ * is_global_init - check if a task structure is init
* @tsk: Task structure to be checked.
*
* Check if a task structure is the first user space task the kernel created.
+ *
+ * TODO: We should inline this function after some cleanups in pid_namespace.h
+ */
+extern int is_global_init(struct task_struct *tsk);
+
+/*
+ * is_container_init:
+ * check whether in the task is init in it's own pid namespace.
*/
-static inline int is_init(struct task_struct *tsk)
+static inline int is_container_init(struct task_struct *tsk)
{
return tsk->pid == 1;
}
Index: lx26-22-rc6-mm1a/kernel/pid.c
===================================================================
--- lx26-22-rc6-mm1a.orig/kernel/pid.c 2007-07-16 12:55:15.000000000 -0700
+++ lx26-22-rc6-mm1a/kernel/pid.c 2007-07-16 13:10:48.000000000 -0700
@@ -69,6 +69,13 @@ struct pid_namespace init_pid_ns = {
.last_pid = 0,
.child_reaper = &init_task
};
+EXPORT_SYMBOL(init_pid_ns);
+
+int is_global_init(struct task_struct *tsk)
+{
+ return tsk == init_pid_ns.child_reaper;
+}
+EXPORT_SYMBOL(is_global_init);
/*
* Note: disable interrupts while the pidmap_lock is held as an
Index: lx26-22-rc6-mm1a/arch/alpha/mm/fault.c
===================================================================
--- lx26-22-rc6-mm1a.orig/arch/alpha/mm/fault.c 2007-07-16 12:55:15.000000000 -0700
+++ lx26-22-rc6-mm1a/arch/alpha/mm/fault.c 2007-07-16 13:10:48.000000000 -0700
@@ -192,7 +192,7 @@ do_page_fault(unsigned long address, uns
/* We ran out of memory, or some other thing happened to us that
made us unable to handle the page fault gracefully. */
out_of_memory:
- if (is_init(current)) {
+ if (is_global_init(current)) {
yield();
down_read(&mm->mmap_sem);
goto survive;
Index: lx26-22-rc6-mm1a/arch/arm/mm/fault.c
===================================================================
--- lx26-22-rc6-mm1a.orig/arch/arm/mm/fault.c 2007-07-16 12:55:15.000000000 -0700
+++ lx26-22-rc6-mm1a/arch/arm/mm/fault.c 2007-07-16 13:10:48.000000000 -0700
@@ -197,7 +197,7 @@ survive:
return fault;
}
- if (!is_init(tsk))
+ if (!is_global_init(tsk))
goto out;
/*
Index: lx26-22-rc6-mm1a/arch/arm26/mm/fault.c
===================================================================
--- lx26-22-rc6-mm1a.orig/arch/arm26/mm/fault.c 2007-07-16 12:55:15.000000000 -0700
+++ lx26-22-rc6-mm1a/arch/arm26/mm/fault.c 2007-07-16 13:10:48.000000000 -0700
@@ -185,7 +185,7 @@ survive:
}
fault = -3; /* out of memory */
- if (!is_init(tsk))
+ if (!is_global_init(tsk))
goto out;
/*
Index: lx26-22-rc6-mm1a/arch/i386/lib/usercopy.c
===================================================================
--- lx26-22-rc6-mm1a.orig/arch/i386/lib/usercopy.c 2007-07-16 12:55:15.000000000 -0700
+++ lx26-22-rc6-mm1a/arch/i386/lib/usercopy.c 2007-07-16 13:10:48.000000000 -0700
@@ -748,7 +748,7 @@ survive:
retval = get_user_pages(current, current->mm,
(unsigned long )to, 1, 1, 0, &pg, NULL);
- if (retval == -ENOMEM && is_init(current)) {
+ if (retval == -ENOMEM && is_global_init(current)) {
up_read(¤t->mm->mmap_sem);
congestion_wait(WRITE, HZ/50);
goto survive;
Index: lx26-22-rc6-mm1a/arch/i386/mm/fault.c
===================================================================
--- lx26-22-rc6-mm1a.orig/arch/i386/mm/fault.c 2007-07-16 12:55:15.000000000 -0700
+++ lx26-22-rc6-mm1a/arch/i386/mm/fault.c 2007-07-16 13:10:48.000000000 -0700
@@ -595,7 +595,7 @@ no_context:
*/
out_of_memory:
up_read(&mm->mmap_sem);
- if (is_init(tsk)) {
+ if (is_global_init(tsk)) {
yield();
down_read(&mm->mmap_sem);
goto survive;
Index: lx26-22-rc6-mm1a/arch/ia64/mm/fault.c
===================================================================
--- lx26-22-rc6-mm1a.orig/arch/ia64/mm/fault.c 2007-07-16 12:55:15.000000000 -0700
+++ lx26-22-rc6-mm1a/arch/ia64/mm/fault.c 2007-07-16 13:10:48.000000000 -0700
@@ -270,7 +270,7 @@ ia64_do_page_fault (unsigned long addres
out_of_memory:
up_read(&mm->mmap_sem);
- if (is_init(current)) {
+ if (is_global_init(current)) {
yield();
down_read(&mm->mmap_sem);
goto survive;
Index: lx26-22-rc6-mm1a/arch/m68k/mm/fault.c
===================================================================
--- lx26-22-rc6-mm1a.orig/arch/m68k/mm/fault.c 2007-07-16 12:55:15.000000000 -0700
+++ lx26-22-rc6-mm1a/arch/m68k/mm/fault.c 2007-07-16 13:10:48.000000000 -0700
@@ -181,7 +181,7 @@ good_area:
*/
out_of_memory:
up_read(&mm->mmap_sem);
- if (is_init(current)) {
+ if (is_global_init(current)) {
yield();
down_read(&mm->mmap_sem);
goto survive;
Index: lx26-22-rc6-mm1a/arch/mips/mm/fault.c
===================================================================
--- lx26-22-rc6-mm1a.orig/arch/mips/mm/fault.c 2007-07-16 12:55:15.000000000 -0700
+++ lx26-22-rc6-mm1a/arch/mips/mm/fault.c 2007-07-16 13:10:48.000000000 -0700
@@ -174,7 +174,7 @@ no_context:
*/
out_of_memory:
up_read(&mm->mmap_sem);
- if (is_init(tsk)) {
+ if (is_global_init(tsk)) {
yield();
down_read(&mm->mmap_sem);
goto survive;
Index: lx26-22-rc6-mm1a/arch/powerpc/kernel/traps.c
===================================================================
--- lx26-22-rc6-mm1a.orig/arch/powerpc/kernel/traps.c 2007-07-16 12:55:15.000000000 -0700
+++ lx26-22-rc6-mm1a/arch/powerpc/kernel/traps.c 2007-07-16 13:10:48.000000000 -0700
@@ -191,7 +191,7 @@ void _exception(int signr, struct pt_reg
* generate the same exception over and over again and we get
* nowhere. Better to kill it and let the kernel panic.
*/
- if (is_init(current)) {
+ if (is_global_init(current)) {
__sighandler_t handler;
spin_lock_irq(¤t->sighand->siglock);
Index: lx26-22-rc6-mm1a/arch/powerpc/mm/fault.c
===================================================================
--- lx26-22-rc6-mm1a.orig/arch/powerpc/mm/fault.c 2007-07-16 12:55:15.000000000 -0700
+++ lx26-22-rc6-mm1a/arch/powerpc/mm/fault.c 2007-07-16 13:10:48.000000000 -0700
@@ -374,7 +374,7 @@ bad_area_nosemaphore:
*/
out_of_memory:
up_read(&mm->mmap_sem);
- if (is_init(current)) {
+ if (is_global_init(current)) {
yield();
down_read(&mm->mmap_sem);
goto survive;
Index: lx26-22-rc6-mm1a/arch/powerpc/platforms/pseries/ras.c
===================================================================
--- lx26-22-rc6-mm1a.orig/arch/powerpc/platforms/pseries/ras.c 2007-07-16 12:55:15.000000000 -0700
+++ lx26-22-rc6-mm1a/arch/powerpc/platforms/pseri
...