From: Serge E. Hallyn 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 Signed-off-by: Sukadev Bhattiprolu Acked-by: Pavel Emelianov Cc: Eric W. Biederman Cc: Cedric Le Goater Cc: Dave Hansen Cc: Herbert Poetzel Cc: Kirill Korotaev Signed-off-by: Andrew Morton --- 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(-) diff -puN arch/alpha/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init arch/alpha/mm/fault.c --- a/arch/alpha/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/alpha/mm/fault.c @@ -188,7 +188,7 @@ 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; diff -puN arch/arm/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init arch/arm/mm/fault.c --- a/arch/arm/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/arm/mm/fault.c @@ -197,7 +197,7 @@ survive: return fault; out_of_memory: - if (!is_init(tsk)) + if (!is_global_init(tsk)) goto out; /* diff -puN arch/arm26/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init arch/arm26/mm/fault.c --- a/arch/arm26/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/arm26/mm/fault.c @@ -185,7 +185,7 @@ survive: out_of_memory: fault = -3; /* out of memory */ - if (!is_init(tsk)) + if (!is_global_init(tsk)) goto out; /* diff -puN arch/avr32/kernel/traps.c~pid-namespaces-define-is_global_init-and-is_container_init arch/avr32/kernel/traps.c --- a/arch/avr32/kernel/traps.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/avr32/kernel/traps.c @@ -89,7 +89,7 @@ void _exception(long signr, struct pt_re * 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 -puN arch/avr32/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init arch/avr32/mm/fault.c --- a/arch/avr32/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/avr32/mm/fault.c @@ -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); diff -puN arch/i386/lib/usercopy.c~pid-namespaces-define-is_global_init-and-is_container_init arch/i386/lib/usercopy.c --- a/arch/i386/lib/usercopy.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/i386/lib/usercopy.c @@ -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; diff -puN arch/i386/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init arch/i386/mm/fault.c --- a/arch/i386/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/i386/mm/fault.c @@ -594,7 +594,7 @@ 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; diff -puN arch/ia64/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init arch/ia64/mm/fault.c --- a/arch/ia64/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/ia64/mm/fault.c @@ -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; diff -puN arch/m68k/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init arch/m68k/mm/fault.c --- a/arch/m68k/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/m68k/mm/fault.c @@ -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; diff -puN arch/mips/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init arch/mips/mm/fault.c --- a/arch/mips/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/mips/mm/fault.c @@ -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; diff -puN arch/powerpc/kernel/traps.c~pid-namespaces-define-is_global_init-and-is_container_init arch/powerpc/kernel/traps.c --- a/arch/powerpc/kernel/traps.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/powerpc/kernel/traps.c @@ -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); diff -puN arch/powerpc/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init arch/powerpc/mm/fault.c --- a/arch/powerpc/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/powerpc/mm/fault.c @@ -376,7 +376,7 @@ 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; diff -puN arch/powerpc/platforms/pseries/ras.c~pid-namespaces-define-is_global_init-and-is_container_init arch/powerpc/platforms/pseries/ras.c --- a/arch/powerpc/platforms/pseries/ras.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/powerpc/platforms/pseries/ras.c @@ -332,7 +332,7 @@ static int recover_mce(struct pt_regs *r 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 -puN arch/ppc/kernel/traps.c~pid-namespaces-define-is_global_init-and-is_container_init arch/ppc/kernel/traps.c --- a/arch/ppc/kernel/traps.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/ppc/kernel/traps.c @@ -121,7 +121,7 @@ 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); diff -puN arch/ppc/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init arch/ppc/mm/fault.c --- a/arch/ppc/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/ppc/mm/fault.c @@ -291,7 +291,7 @@ 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; diff -puN arch/s390/lib/uaccess_pt.c~pid-namespaces-define-is_global_init-and-is_container_init arch/s390/lib/uaccess_pt.c --- a/arch/s390/lib/uaccess_pt.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/s390/lib/uaccess_pt.c @@ -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; diff -puN arch/s390/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init arch/s390/mm/fault.c --- a/arch/s390/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/s390/mm/fault.c @@ -211,7 +211,7 @@ static int do_out_of_memory(struct pt_re 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 -puN arch/sh/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init arch/sh/mm/fault.c --- a/arch/sh/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/sh/mm/fault.c @@ -203,7 +203,7 @@ 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; diff -puN arch/sh64/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init arch/sh64/mm/fault.c --- a/arch/sh64/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/sh64/mm/fault.c @@ -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; diff -puN arch/um/kernel/trap.c~pid-namespaces-define-is_global_init-and-is_container_init arch/um/kernel/trap.c --- a/arch/um/kernel/trap.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/um/kernel/trap.c @@ -121,7 +121,7 @@ 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); diff -puN arch/x86_64/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init arch/x86_64/mm/fault.c --- a/arch/x86_64/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/x86_64/mm/fault.c @@ -557,7 +557,7 @@ no_context: */ out_of_memory: up_read(&mm->mmap_sem); - if (is_init(current)) { + if (is_global_init(current)) { yield(); goto again; } diff -puN arch/xtensa/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init arch/xtensa/mm/fault.c --- a/arch/xtensa/mm/fault.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/arch/xtensa/mm/fault.c @@ -143,7 +143,7 @@ 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; diff -puN drivers/char/sysrq.c~pid-namespaces-define-is_global_init-and-is_container_init drivers/char/sysrq.c --- a/drivers/char/sysrq.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/drivers/char/sysrq.c @@ -250,7 +250,7 @@ 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); } diff -puN include/linux/sched.h~pid-namespaces-define-is_global_init-and-is_container_init include/linux/sched.h --- a/include/linux/sched.h~pid-namespaces-define-is_global_init-and-is_container_init +++ a/include/linux/sched.h @@ -1270,12 +1270,20 @@ 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; } diff -puN kernel/capability.c~pid-namespaces-define-is_global_init-and-is_container_init kernel/capability.c --- a/kernel/capability.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/kernel/capability.c @@ -12,6 +12,7 @@ #include #include #include +#include #include unsigned securebits = SECUREBITS_DEFAULT; /* systemwide security settings */ @@ -135,7 +136,7 @@ static inline int cap_set_all(kernel_cap int found = 0; do_each_thread(g, target) { - if (target == current || is_init(target)) + if (target == current || is_container_init(target)) continue; found = 1; if (security_capset_check(target, effective, inheritable, diff -puN kernel/exit.c~pid-namespaces-define-is_global_init-and-is_container_init kernel/exit.c --- a/kernel/exit.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/kernel/exit.c @@ -230,7 +230,7 @@ static int will_become_orphaned_pgrp(str 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 -puN kernel/kexec.c~pid-namespaces-define-is_global_init-and-is_container_init kernel/kexec.c --- a/kernel/kexec.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/kernel/kexec.c @@ -41,7 +41,7 @@ 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; } diff -puN kernel/pid.c~pid-namespaces-define-is_global_init-and-is_container_init kernel/pid.c --- a/kernel/pid.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/kernel/pid.c @@ -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 diff -puN kernel/signal.c~pid-namespaces-define-is_global_init-and-is_container_init kernel/signal.c --- a/kernel/signal.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/kernel/signal.c @@ -256,7 +256,7 @@ flush_signal_handlers(struct task_struct 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 -puN kernel/sysctl.c~pid-namespaces-define-is_global_init-and-is_container_init kernel/sysctl.c --- a/kernel/sysctl.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/kernel/sysctl.c @@ -1927,7 +1927,7 @@ int proc_dointvec_bset(ctl_table *table, 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 -puN mm/oom_kill.c~pid-namespaces-define-is_global_init-and-is_container_init mm/oom_kill.c --- a/mm/oom_kill.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/mm/oom_kill.c @@ -222,7 +222,7 @@ static struct task_struct *select_bad_pr if (!p->mm) continue; /* skip the init task */ - if (is_init(p)) + if (is_global_init(p)) continue; /* @@ -275,7 +275,7 @@ static struct task_struct *select_bad_pr */ 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 -puN security/commoncap.c~pid-namespaces-define-is_global_init-and-is_container_init security/commoncap.c --- a/security/commoncap.c~pid-namespaces-define-is_global_init-and-is_container_init +++ a/security/commoncap.c @@ -23,6 +23,7 @@ #include #include #include +#include int cap_netlink_send(struct sock *sk, struct sk_buff *skb) { @@ -252,7 +253,7 @@ void cap_bprm_apply_creds (struct linux_ /* 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; _