Commit b460cbc5 authored by Serge E. Hallyn's avatar Serge E. Hallyn Committed by Linus Torvalds
Browse files

pid namespaces: define is_global_init() and is_container_init()



is_init() is an ambiguous name for the pid==1 check.  Split it into
is_global_init() and is_container_init().

A cgroup 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 cgroup if the cgroup's init has a
	  bug rather than force a kernel panic.

[akpm@linux-foundation.org: fix comment]
[sukadev@us.ibm.com: Use is_global_init() in arch/m32r/mm/fault.c]
[bunk@stusta.de: kernel/pid.c: remove unused exports]
[sukadev@us.ibm.com: Fix capability.c to work with threaded init]
Signed-off-by: default avatarSerge E. Hallyn <serue@us.ibm.com>
Signed-off-by: default avatarSukadev Bhattiprolu <sukadev@us.ibm.com>
Acked-by: default avatarPavel 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>
Cc: Kirill Korotaev <dev@sw.ru>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3743ca05
......@@ -188,7 +188,7 @@ do_page_fault(unsigned long address, unsigned long mmcsr,
/* 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;
......
......@@ -197,7 +197,7 @@ survive:
return fault;
out_of_memory:
if (!is_init(tsk))
if (!is_global_init(tsk))
goto out;
/*
......
......@@ -89,7 +89,7 @@ void _exception(long signr, struct pt_regs *regs, int code,
* 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(&current->sighand->siglock);
......
......@@ -160,7 +160,7 @@ bad_area:
if (exception_trace && printk_ratelimit())
printk("%s%s[%d]: segfault at %08lx pc %08lx "
"sp %08lx ecr %lu\n",
is_init(tsk) ? KERN_EMERG : KERN_INFO,
is_global_init(tsk) ? KERN_EMERG : KERN_INFO,
tsk->comm, tsk->pid, address, regs->pc,
regs->sp, ecr);
_exception(SIGSEGV, regs, code, address);
......@@ -209,7 +209,7 @@ no_context:
*/
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;
......@@ -231,7 +231,7 @@ do_sigbus:
if (exception_trace)
printk("%s%s[%d]: bus error at %08lx pc %08lx "
"sp %08lx ecr %lu\n",
is_init(tsk) ? KERN_EMERG : KERN_INFO,
is_global_init(tsk) ? KERN_EMERG : KERN_INFO,
tsk->comm, tsk->pid, address, regs->pc,
regs->sp, ecr);
......
......@@ -274,7 +274,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
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;
......
......@@ -271,7 +271,7 @@ 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;
......
......@@ -180,7 +180,7 @@ 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;
......
......@@ -173,7 +173,7 @@ 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;
......
......@@ -201,7 +201,7 @@ void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
* 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(&current->sighand->siglock);
......
......@@ -375,7 +375,7 @@ 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;
......
......@@ -332,7 +332,7 @@ static int recover_mce(struct pt_regs *regs, struct rtas_error_log * err)
err->disposition == RTAS_DISP_NOT_RECOVERED &&
err->target == RTAS_TARGET_MEMORY &&
err->type == RTAS_TYPE_ECC_UNCORR &&
!(current->pid == 0 || is_init(current))) {
!(current->pid == 0 || is_global_init(current))) {
/* Kill off a user process with an ECC error */
printk(KERN_ERR "MCE: uncorrectable ecc error for pid %d\n",
current->pid);
......
......@@ -121,7 +121,7 @@ void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
* 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(&current->sighand->siglock);
......
......@@ -290,7 +290,7 @@ bad_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;
......
......@@ -64,7 +64,7 @@ out:
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;
......
......@@ -211,7 +211,7 @@ static int do_out_of_memory(struct pt_regs *regs, unsigned long error_code,
struct mm_struct *mm = tsk->mm;
up_read(&mm->mmap_sem);
if (is_init(tsk)) {
if (is_global_init(tsk)) {
yield();
down_read(&mm->mmap_sem);
return 1;
......
......@@ -207,7 +207,7 @@ no_context:
*/
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;
......
......@@ -278,7 +278,7 @@ bad_area:
show_regs(regs);
#endif
}
if (is_init(tsk)) {
if (is_global_init(tsk)) {
panic("INIT had user mode bad_area\n");
}
tsk->thread.address = address;
......@@ -320,14 +320,14 @@ no_context:
* us unable to handle the page fault gracefully.
*/
out_of_memory:
if (is_init(current)) {
if (is_global_init(current)) {
panic("INIT out of memory\n");
yield();
goto survive;
}
printk("fault:Out of memory\n");
up_read(&mm->mmap_sem);
if (is_init(current)) {
if (is_global_init(current)) {
yield();
down_read(&mm->mmap_sem);
goto survive;
......
......@@ -108,7 +108,7 @@ out_nosemaphore:
* us unable to handle the page fault gracefully.
*/
out_of_memory:
if (is_init(current)) {
if (is_global_init(current)) {
up_read(&mm->mmap_sem);
yield();
down_read(&mm->mmap_sem);
......
......@@ -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(&current->mm->mmap_sem);
congestion_wait(WRITE, HZ/50);
goto survive;
......
......@@ -587,7 +587,7 @@ 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;
......
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