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pid namespaces: define is_global_init() and is_container_init()

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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: 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>
Cc: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Serge E. Hallyn 2007-10-18 23:39:52 -07:00 committed by Linus Torvalds
parent 3743ca05ff
commit b460cbc581
32 changed files with 52 additions and 37 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/alpha/mm/fault.c
View File

@ -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;

2
arch/arm/mm/fault.c
View File

@ -197,7 +197,7 @@ __do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
return fault;
out_of_memory:
if (!is_init(tsk))
if (!is_global_init(tsk))
goto out;
/*

2
arch/avr32/kernel/traps.c
View File

@ -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);

6
arch/avr32/mm/fault.c
View File

@ -160,7 +160,7 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
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 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
*/
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 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
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);

2
arch/ia64/mm/fault.c
View File

@ -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;

2
arch/m32r/mm/fault.c
View File

@ -271,7 +271,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code,
*/
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;

2
arch/m68k/mm/fault.c
View File

@ -180,7 +180,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
*/
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;

2
arch/mips/mm/fault.c
View File

@ -173,7 +173,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
*/
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;

2
arch/powerpc/kernel/traps.c
View File

@ -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);

2
arch/powerpc/mm/fault.c
View File

@ -375,7 +375,7 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
*/
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;

2
arch/powerpc/platforms/pseries/ras.c
View File

@ -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);

2
arch/ppc/kernel/traps.c
View File

@ -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);

2
arch/ppc/mm/fault.c
View File

@ -290,7 +290,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
*/
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;

2
arch/s390/lib/uaccess_pt.c
View File

@ -64,7 +64,7 @@ static int __handle_fault(struct mm_struct *mm, unsigned long address,
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;

2
arch/s390/mm/fault.c
View File

@ -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;

2
arch/sh/mm/fault.c
View File

@ -207,7 +207,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
*/
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;

6
arch/sh64/mm/fault.c
View File

@ -278,7 +278,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long writeaccess,
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 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long writeaccess,
* 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;

2
arch/um/kernel/trap.c
View File

@ -108,7 +108,7 @@ int handle_page_fault(unsigned long address, unsigned long ip,
* 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);

2
arch/x86/lib/usercopy_32.c
View File

@ -748,7 +748,7 @@ unsigned long __copy_to_user_ll(void __user *to, const void *from,
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;

2
arch/x86/mm/fault_32.c
View File

@ -587,7 +587,7 @@ fastcall void __kprobes do_page_fault(struct pt_regs *regs,
*/
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;

2
arch/x86/mm/fault_64.c
View File

@ -554,7 +554,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
*/
out_of_memory:
up_read(&mm->mmap_sem);
if (is_init(current)) {
if (is_global_init(current)) {
yield();
goto again;
}

2
arch/xtensa/mm/fault.c
View File

@ -145,7 +145,7 @@ void do_page_fault(struct pt_regs *regs)
*/
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;

2
drivers/char/sysrq.c
View File

@ -251,7 +251,7 @@ static void send_sig_all(int sig)
struct task_struct *p;
for_each_process(p) {
if (p->mm && !is_init(p))
if (p->mm && !is_global_init(p))
/* Not swapper, init nor kernel thread */
force_sig(sig, p);
}

12
include/linux/sched.h
View File

@ -1237,12 +1237,20 @@ static inline int pid_alive(struct task_struct *p)
}
/**
* 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
*/
static inline int is_init(struct task_struct *tsk)
extern int is_global_init(struct task_struct *tsk);
/*
* is_container_init:
* check whether in the task is init in its own pid namespace.
*/
static inline int is_container_init(struct task_struct *tsk)
{
return tsk->pid == 1;
}

3
kernel/capability.c
View File

@ -12,6 +12,7 @@
#include <linux/module.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/pid_namespace.h>
#include <asm/uaccess.h>
/*
@ -129,7 +130,7 @@ static inline int cap_set_all(kernel_cap_t *effective,
int found = 0;
do_each_thread(g, target) {
if (target == current || is_init(target))
if (target == current || is_container_init(target->group_leader))
continue;
found = 1;
if (security_capset_check(target, effective, inheritable,

2
kernel/exit.c
View File

@ -221,7 +221,7 @@ static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignor
do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
if (p == ignored_task
|| p->exit_state
|| is_init(p->real_parent))
|| is_global_init(p->real_parent))
continue;
if (task_pgrp(p->real_parent) != pgrp &&
task_session(p->real_parent) == task_session(p)) {

2
kernel/kexec.c
View File

@ -51,7 +51,7 @@ struct resource crashk_res = {
int kexec_should_crash(struct task_struct *p)
{
if (in_interrupt() || !p->pid || is_init(p) || panic_on_oops)
if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
return 1;
return 0;
}

5
kernel/pid.c
View File

@ -70,6 +70,11 @@ struct pid_namespace init_pid_ns = {
.child_reaper = &init_task
};
int is_global_init(struct task_struct *tsk)
{
return tsk == init_pid_ns.child_reaper;
}
/*
* Note: disable interrupts while the pidmap_lock is held as an
* interrupt might come in and do read_lock(&tasklist_lock).

2
kernel/signal.c
View File

@ -256,7 +256,7 @@ flush_signal_handlers(struct task_struct *t, int force_default)
int unhandled_signal(struct task_struct *tsk, int sig)
{
if (is_init(tsk))
if (is_global_init(tsk))
return 1;
if (tsk->ptrace & PT_PTRACED)
return 0;

2
kernel/sysctl.c
View File

@ -1888,7 +1888,7 @@ int proc_dointvec_bset(struct ctl_table *table, int write, struct file *filp,
return -EPERM;
}
op = is_init(current) ? OP_SET : OP_AND;
op = is_global_init(current) ? OP_SET : OP_AND;
return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
do_proc_dointvec_bset_conv,&op);
}

4
mm/oom_kill.c
View File

@ -212,7 +212,7 @@ static struct task_struct *select_bad_process(unsigned long *ppoints)
if (!p->mm)
continue;
/* skip the init task */
if (is_init(p))
if (is_global_init(p))
continue;
/*
@ -265,7 +265,7 @@ static struct task_struct *select_bad_process(unsigned long *ppoints)
*/
static void __oom_kill_task(struct task_struct *p, int verbose)
{
if (is_init(p)) {
if (is_global_init(p)) {
WARN_ON(1);
printk(KERN_WARNING "tried to kill init!\n");
return;

3
security/commoncap.c
View File

@ -23,6 +23,7 @@
#include <linux/xattr.h>
#include <linux/hugetlb.h>
#include <linux/mount.h>
#include <linux/sched.h>
#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
/*
@ -334,7 +335,7 @@ void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
/* For init, we want to retain the capabilities set
* in the init_task struct. Thus we skip the usual
* capability rules */
if (!is_init(current)) {
if (!is_global_init(current)) {
current->cap_permitted = new_permitted;
current->cap_effective = bprm->cap_effective ?
new_permitted : 0;