This changes CLONE_PID ("if my pid is 0, copy it") to CLONE_IDLETASK
("if I have CAP_SYS_MODULE, set child's pid to zero").
This is requires for creating new idle processes without being an idle
process.
Rusty.
-- Anyone who quotes me in their sig is an idiot. -- Rusty Russell.Name: CLONE_PID removal, CLONE_INITTASK added. Author: Rusty Russell Depends: Hotcpu/do-fork.patch.gz
D: This patch cleans up the idle thread creation code by redefining D: CLONE_PID to CLONE_IDLETASK: "create a 0-pid process".
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/include/linux/sched.h working-2.5.14-dofork+clonepid/include/linux/sched.h --- working-2.5.14-dofork/include/linux/sched.h Thu May 9 18:30:41 2002 +++ working-2.5.14-dofork+clonepid/include/linux/sched.h Thu May 9 18:25:21 2002 @@ -39,7 +39,7 @@ #define CLONE_FS 0x00000200 /* set if fs info shared between processes */ #define CLONE_FILES 0x00000400 /* set if open files shared between processes */ #define CLONE_SIGHAND 0x00000800 /* set if signal handlers and blocked signals shared */ -#define CLONE_PID 0x00001000 /* set if pid shared */ +#define CLONE_IDLETASK 0x00001000 /* set if new pid should be 0 */ #define CLONE_PTRACE 0x00002000 /* set if we want to let tracing continue on the child too */ #define CLONE_VFORK 0x00004000 /* set if the parent wants the child to wake it up on mm_release */ #define CLONE_PARENT 0x00008000 /* set if we want to have the same parent as the cloner */ diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/alpha/kernel/smp.c working-2.5.14-dofork+clonepid/arch/alpha/kernel/smp.c --- working-2.5.14-dofork/arch/alpha/kernel/smp.c Thu Mar 21 14:14:37 2002 +++ working-2.5.14-dofork+clonepid/arch/alpha/kernel/smp.c Thu May 9 18:25:22 2002 @@ -439,7 +439,7 @@ /* Don't care about the contents of regs since we'll never reschedule the forked task. */ struct pt_regs regs; - return do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0); + return do_fork(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0); } /* diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/i386/kernel/smpboot.c working-2.5.14-dofork+clonepid/arch/i386/kernel/smpboot.c --- working-2.5.14-dofork/arch/i386/kernel/smpboot.c Thu May 9 18:30:41 2002 +++ working-2.5.14-dofork+clonepid/arch/i386/kernel/smpboot.c Thu May 9 18:25:22 2002 @@ -536,7 +536,7 @@ * don't care about the eip and regs settings since * we'll never reschedule the forked task. */ - return do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0); + return do_fork(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0); } /* which physical APIC ID maps to which logical CPU number */ diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/ia64/kernel/smpboot.c working-2.5.14-dofork+clonepid/arch/ia64/kernel/smpboot.c --- working-2.5.14-dofork/arch/ia64/kernel/smpboot.c Tue Apr 23 11:39:33 2002 +++ working-2.5.14-dofork+clonepid/arch/ia64/kernel/smpboot.c Thu May 9 18:25:22 2002 @@ -398,7 +398,7 @@ * don't care about the eip and regs settings since * we'll never reschedule the forked task. */ - return do_fork(CLONE_VM|CLONE_PID, 0, 0, 0); + return do_fork(CLONE_VM|CLONE_IDLETASK, 0, 0, 0); } static void __init diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/mips/kernel/smp.c working-2.5.14-dofork+clonepid/arch/mips/kernel/smp.c --- working-2.5.14-dofork/arch/mips/kernel/smp.c Mon Apr 15 11:47:11 2002 +++ working-2.5.14-dofork+clonepid/arch/mips/kernel/smp.c Thu May 9 18:25:22 2002 @@ -122,7 +122,7 @@ /* Spawn a new process normally. Grab a pointer to its task struct so we can mess with it */ - do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0); + do_fork(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0); p = prev_task(&init_task); /* Schedule the first task manually */ @@ -151,7 +151,7 @@ * The following code is purely to make sure * Linux can schedule processes on this slave. */ - kernel_thread(0, NULL, CLONE_PID); + kernel_thread(0, NULL, CLONE_IDLETASK); p = prev_task(&init_task); sprintf(p->comm, "%s%d", "Idle", i); init_tasks[i] = p; diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/mips64/sgi-ip27/ip27-init.c working-2.5.14-dofork+clonepid/arch/mips64/sgi-ip27/ip27-init.c --- working-2.5.14-dofork/arch/mips64/sgi-ip27/ip27-init.c Thu Mar 21 14:14:41 2002 +++ working-2.5.14-dofork+clonepid/arch/mips64/sgi-ip27/ip27-init.c Thu May 9 18:25:22 2002 @@ -490,7 +490,7 @@ * The following code is purely to make sure * Linux can schedule processes on this slave. */ - kernel_thread(0, NULL, CLONE_PID); + kernel_thread(0, NULL, CLONE_IDLETASK); p = prev_task(&init_task); sprintf(p->comm, "%s%d", "Idle", num_cpus); init_tasks[num_cpus] = p; diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/ppc/kernel/smp.c working-2.5.14-dofork+clonepid/arch/ppc/kernel/smp.c --- working-2.5.14-dofork/arch/ppc/kernel/smp.c Thu May 9 18:30:41 2002 +++ working-2.5.14-dofork+clonepid/arch/ppc/kernel/smp.c Thu May 9 18:26:00 2002 @@ -343,7 +343,7 @@ /* create a process for the processor */ /* only regs.msr is actually used, and 0 is OK for it */ memset(®s, 0, sizeof(struct pt_regs)); - p = do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0); + p = do_fork(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0); if (IS_ERR(p)) panic("failed fork for CPU %d", i); init_idle(p, i); diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/ppc64/kernel/smp.c working-2.5.14-dofork+clonepid/arch/ppc64/kernel/smp.c --- working-2.5.14-dofork/arch/ppc64/kernel/smp.c Mon May 6 11:11:52 2002 +++ working-2.5.14-dofork+clonepid/arch/ppc64/kernel/smp.c Thu May 9 18:25:22 2002 @@ -640,7 +640,7 @@ memset(®s, 0, sizeof(struct pt_regs)); - if (do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0) < 0) + if (do_fork(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0) < 0) panic("failed fork for CPU %d", i); p = prev_task(&init_task); if (!p) diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/s390/kernel/smp.c working-2.5.14-dofork+clonepid/arch/s390/kernel/smp.c --- working-2.5.14-dofork/arch/s390/kernel/smp.c Thu Mar 21 14:14:41 2002 +++ working-2.5.14-dofork+clonepid/arch/s390/kernel/smp.c Thu May 9 18:25:22 2002 @@ -511,7 +511,7 @@ /* don't care about the psw and regs settings since we'll never reschedule the forked task. */ memset(®s,0,sizeof(struct pt_regs)); - return do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0); + return do_fork(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0); } static void __init do_boot_cpu(int cpu) diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/s390x/kernel/smp.c working-2.5.14-dofork+clonepid/arch/s390x/kernel/smp.c --- working-2.5.14-dofork/arch/s390x/kernel/smp.c Thu Mar 21 14:14:41 2002 +++ working-2.5.14-dofork+clonepid/arch/s390x/kernel/smp.c Thu May 9 18:25:22 2002 @@ -490,7 +490,7 @@ /* don't care about the psw and regs settings since we'll never reschedule the forked task. */ memset(®s,0,sizeof(struct pt_regs)); - return do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0); + return do_fork(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0); } static void __init do_boot_cpu(int cpu) diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/sparc/kernel/sun4d_smp.c working-2.5.14-dofork+clonepid/arch/sparc/kernel/sun4d_smp.c --- working-2.5.14-dofork/arch/sparc/kernel/sun4d_smp.c Mon May 6 16:00:09 2002 +++ working-2.5.14-dofork+clonepid/arch/sparc/kernel/sun4d_smp.c Thu May 9 18:25:22 2002 @@ -214,7 +214,7 @@ int no; /* Cook up an idler for this guy. */ - kernel_thread(start_secondary, NULL, CLONE_PID); + kernel_thread(start_secondary, NULL, CLONE_IDLETASK); cpucount++; diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/sparc/kernel/sun4m_smp.c working-2.5.14-dofork+clonepid/arch/sparc/kernel/sun4m_smp.c --- working-2.5.14-dofork/arch/sparc/kernel/sun4m_smp.c Mon May 6 16:00:09 2002 +++ working-2.5.14-dofork+clonepid/arch/sparc/kernel/sun4m_smp.c Thu May 9 18:25:22 2002 @@ -187,7 +187,7 @@ int timeout; /* Cook up an idler for this guy. */ - kernel_thread(start_secondary, NULL, CLONE_PID); + kernel_thread(start_secondary, NULL, CLONE_IDLETASK); cpucount++; diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/sparc64/kernel/smp.c working-2.5.14-dofork+clonepid/arch/sparc64/kernel/smp.c --- working-2.5.14-dofork/arch/sparc64/kernel/smp.c Mon May 6 11:11:52 2002 +++ working-2.5.14-dofork+clonepid/arch/sparc64/kernel/smp.c Thu May 9 18:25:22 2002 @@ -268,7 +268,7 @@ int no; prom_printf("Starting CPU %d... ", i); - kernel_thread(NULL, NULL, CLONE_PID); + kernel_thread(NULL, NULL, CLONE_IDLETASK); cpucount++; p = prev_task(&init_task); diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/x86_64/kernel/smpboot.c working-2.5.14-dofork+clonepid/arch/x86_64/kernel/smpboot.c --- working-2.5.14-dofork/arch/x86_64/kernel/smpboot.c Tue Apr 23 11:39:33 2002 +++ working-2.5.14-dofork+clonepid/arch/x86_64/kernel/smpboot.c Thu May 9 18:25:22 2002 @@ -483,7 +483,7 @@ * don't care about the rip and regs settings since * we'll never reschedule the forked task. */ - return do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0); + return do_fork(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0); } #if APIC_DEBUG diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/kernel/fork.c working-2.5.14-dofork+clonepid/kernel/fork.c --- working-2.5.14-dofork/kernel/fork.c Thu May 9 18:30:41 2002 +++ working-2.5.14-dofork+clonepid/kernel/fork.c Thu May 9 18:25:22 2002 @@ -136,8 +136,8 @@ struct task_struct *p; int pid; - if (flags & CLONE_PID) - return current->pid; + if (flags & CLONE_IDLETASK) + return 0; spin_lock(&lastpid_lock); if((++last_pid) & 0xffff8000) { @@ -624,13 +624,10 @@ retval = -EPERM; /* - * CLONE_PID is only allowed for the initial SMP swapper - * calls + * CLONE_IDLETASK is used to create idle threads. */ - if (clone_flags & CLONE_PID) { - if (current->pid) - goto fork_out; - } + if ((clone_flags & CLONE_IDLETASK) && !capable(CAP_SYS_MODULE)) + goto fork_out; retval = -ENOMEM; p = dup_task_struct(current); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/