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: 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>
diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c
index 25154df..e0593e6 100644
--- a/arch/alpha/mm/fault.c
+++ b/arch/alpha/mm/fault.c
@@ -188,7 +188,7 @@
/* 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;
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index 59ed1d0..a8a7dab 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -197,7 +197,7 @@
return fault;
out_of_memory:
- if (!is_init(tsk))
+ if (!is_global_init(tsk))
goto out;
/*
diff --git a/arch/avr32/kernel/traps.c b/arch/avr32/kernel/traps.c
index 9a73ce7..8a7caf8e 100644
--- a/arch/avr32/kernel/traps.c
+++ b/arch/avr32/kernel/traps.c
@@ -89,7 +89,7 @@
* 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);
diff --git a/arch/avr32/mm/fault.c b/arch/avr32/mm/fault.c
index 11472f8..6560cb1 100644
--- a/arch/avr32/mm/fault.c
+++ b/arch/avr32/mm/fault.c
@@ -160,7 +160,7 @@
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 @@
*/
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 @@
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);
diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
index 32f2625..7571076 100644
--- a/arch/ia64/mm/fault.c
+++ b/arch/ia64/mm/fault.c
@@ -274,7 +274,7 @@
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;
diff --git a/arch/m32r/mm/fault.c b/arch/m32r/mm/fault.c
index 70a766a..4a71df4 100644
--- a/arch/m32r/mm/fault.c
+++ b/arch/m32r/mm/fault.c
@@ -271,7 +271,7 @@
*/
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;
diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c
index eaa6186..f493f03 100644
--- a/arch/m68k/mm/fault.c
+++ b/arch/m68k/mm/fault.c
@@ -180,7 +180,7 @@
*/
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;
diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c
index 5699c77..fa636fc 100644
--- a/arch/mips/mm/fault.c
+++ b/arch/mips/mm/fault.c
@@ -173,7 +173,7 @@
*/
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;
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index bf9e39c..9fb4a68 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -201,7 +201,7 @@
* 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);
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index ab3546c..a18fda3 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -375,7 +375,7 @@
*/
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;
diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
index 3a393c7..a1ab25c 100644
--- a/arch/powerpc/platforms/pseries/ras.c
+++ b/arch/powerpc/platforms/pseries/ras.c
@@ -332,7 +332,7 @@
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);
diff --git a/arch/ppc/kernel/traps.c b/arch/ppc/kernel/traps.c
index 3f3b292..c785689 100644
--- a/arch/ppc/kernel/traps.c
+++ b/arch/ppc/kernel/traps.c
@@ -121,7 +121,7 @@
* 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);
diff --git a/arch/ppc/mm/fault.c b/arch/ppc/mm/fault.c
index 94913dd..254c23b 100644
--- a/arch/ppc/mm/fault.c
+++ b/arch/ppc/mm/fault.c
@@ -290,7 +290,7 @@
*/
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;
diff --git a/arch/s390/lib/uaccess_pt.c b/arch/s390/lib/uaccess_pt.c
index 60604b2..b159a9d 100644
--- a/arch/s390/lib/uaccess_pt.c
+++ b/arch/s390/lib/uaccess_pt.c
@@ -64,7 +64,7 @@
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;
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 14c241c..2456b52 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -211,7 +211,7 @@
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;
diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
index 4729668..f33cedb 100644
--- a/arch/sh/mm/fault.c
+++ b/arch/sh/mm/fault.c
@@ -207,7 +207,7 @@
*/
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;
diff --git a/arch/sh64/mm/fault.c b/arch/sh64/mm/fault.c
index dd81c66..7aea586 100644
--- a/arch/sh64/mm/fault.c
+++ b/arch/sh64/mm/fault.c
@@ -278,7 +278,7 @@
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 @@
* 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;
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index bd06055..cb3321f 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -108,7 +108,7 @@
* 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);
diff --git a/arch/x86/lib/usercopy_32.c b/arch/x86/lib/usercopy_32.c
index 9f38b12..8bab2b2 100644
--- a/arch/x86/lib/usercopy_32.c
+++ b/arch/x86/lib/usercopy_32.c
@@ -748,7 +748,7 @@
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;
diff --git a/arch/x86/mm/fault_32.c b/arch/x86/mm/fault_32.c
index 6555c3d..4fc5e40 100644
--- a/arch/x86/mm/fault_32.c
+++ b/arch/x86/mm/fault_32.c
@@ -587,7 +587,7 @@
*/
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;
diff --git a/arch/x86/mm/fault_64.c b/arch/x86/mm/fault_64.c
index 5e0e549..5149ac1 100644
--- a/arch/x86/mm/fault_64.c
+++ b/arch/x86/mm/fault_64.c
@@ -554,7 +554,7 @@
*/
out_of_memory:
up_read(&mm->mmap_sem);
- if (is_init(current)) {
+ if (is_global_init(current)) {
yield();
goto again;
}
diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c
index 2f84285..33f366b 100644
--- a/arch/xtensa/mm/fault.c
+++ b/arch/xtensa/mm/fault.c
@@ -145,7 +145,7 @@
*/
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;
diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
index 78d1493..de60e1e 100644
--- a/drivers/char/sysrq.c
+++ b/drivers/char/sysrq.c
@@ -251,7 +251,7 @@
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);
}
diff --git a/include/linux/sched.h b/include/linux/sched.h
index df6049e..47cf81d 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1237,12 +1237,20 @@
}
/**
- * 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;
}
diff --git a/kernel/capability.c b/kernel/capability.c
index cbc5fd6..f02ad47 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -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 @@
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,
diff --git a/kernel/exit.c b/kernel/exit.c
index d1eddc7..d22aefa 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -221,7 +221,7 @@
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)) {
diff --git a/kernel/kexec.c b/kernel/kexec.c
index e9f1b4e..fbffdb4 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -51,7 +51,7 @@
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;
}
diff --git a/kernel/pid.c b/kernel/pid.c
index 78c0dbf..bb07851 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -70,6 +70,11 @@
.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).
diff --git a/kernel/signal.c b/kernel/signal.c
index 0a6d372..8214ffa 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -256,7 +256,7 @@
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;
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 067554b..44868e4 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1888,7 +1888,7 @@
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);
}
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index a64decb..b1c2d0f 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -212,7 +212,7 @@
if (!p->mm)
continue;
/* skip the init task */
- if (is_init(p))
+ if (is_global_init(p))
continue;
/*
@@ -265,7 +265,7 @@
*/
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;
diff --git a/security/commoncap.c b/security/commoncap.c
index 48ca5b0..43f9027 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -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 @@
/* 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;